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The copyright of the material in this book belongs to the individual contributors and any unauthorized reproduction of the material is prohibited. Printed in Sweden by Media-Tryck, Lund, 2012

Welcome to Malmö/Lund and ECIS2012 Colloid and interface science is an interdisciplinary field that embraces many scientific disciplines, from nano-science, physics and chemistry to biology and medicine. Much of the fundamental knowledge on colloidal and interfacial processes have and will be key for the development of a sustainable processes. The Malmö-Lund region is located in the heart of the Øresund region with a large number of research institutions, both on the Swedish and Danish side. Recent decisions to locate two major research facilities in Lund, European Spallation Source (ESS) and the Max IV synchrotron, will further expand the research infrastructure in the region. A visit to the MAX IV and ESS sites in conjunction with the conference dinner in Lund will be organised. One of the founding fathers of ECIS, Professor Björn Lindman, is honored by a symposium, “Outlooks from strong traditions in colloid and interface science”, on Friday 7 September. We are happy that so many participants, almost 500, from both Europe and overseas have chosen to visit Malmö/Lund and wish you all very welcome! Marie-Lousie Ainalem, ESS Thomas Arnebrant, Malmö University Zoltan Blum, Malmö University Birgit Johansson, Lund University Vitaly Kocherbitov, Malmö University Tommy Nylander, Lund University Christelle Prinz, Lund University

Oral Sessions (abstracts in separate book)

1. Interfacial Phenomena and Structures (Monday + Wednesday pm in “Teatern”)

2. Surfactants, Lipids, and Self-Assembly (Monday in “Södra Hallen”) 3. Colloids and Colloidal Stability (Wednesday in “Södra Hallen”) 4. Polymers, Biopolymers, and Polyelectrolytes (Tuesday in “Södra Hallen”) 5. Hydration Phenomena (Friday am in “Södra Hallen”) 6. Nanostructered Materials (Tuesday in “Teatern”) 7. Biocolloids/Interfaces (Wednesday in “Teatern”) 8. Soft Matter Formulations (Thursday am in “Södra Hallen”) 9. Neutrons and Synchrotron Radiation Revealing Colloidal and Interfacial

Structure and Dynamics (Thursday am + Friday am in “Teatern”) C COST action (Tuesday + Wednesday in “Separaten”)

Day of poster presentations in “Saluhallen”

Monday 3 September P1:1-.. odd # 17.00-18.00 & even # 18.00-19.00 Tuesday 4 September P2:1-.. odd # 17.00-18.00 & even # 18.00-19.00 Wednesday 5 September P3:1-.. odd # 17.00-18.00 & even # 18.00-19.00

ECIS 2012 SPONSORS

Malmö stad

We are very greatful to the following sponsors & exhibitors for supporting the 26th ECIS Conference:

The Swedish Chemical Society

The Royal Physiographic Society in Lund

MONDAY

Monday 3 Sept: Poster presented 17.00-18.00 P1:1

Spatial imaging and evaluation of humectants impact on stratum corneum hydration with confocal Raman microscpectroscopy Cathrine Albèr 1; Birgit D. Brandner 2; Peter Billsten 3; Johan Engblom 4 1Malmö University, Biomedical Science, Malmö, Sweden; 2Institute of Surface Chemistry, Stockholm, Sweden; 3PerkinElmer, Upplands Väsby, Sweden; 4Biomedical Science, Malmö, Sweden

Confocal Raman microspectroscopy (CRM) enables non-invasive depth-scanning of biological tissues. The technique has been used to obtain information about the molecular composition of the skin, tracking of externally applied compounds and to determine molecular concentration profiles. The objective of this study is to use CRM in order to evaluate the changes in stratum corneum hydration when applying polyethylene glycol and the humectants urea and glycerol, and thereby also varying the external chemical potential of water. In the present study we also utilize the advantages of CRM to create novel spatial high- resolution Raman images of stratum corneum. Excised porcine skin membranes (500 nm in thickness) were equilibrated from the surface with phosphate buffered saline (PBS) together with different types of humectants using Franz cells. The Raman measurements were performed with a WITec alpha300 system (Ulm, Germany) equipped with a 532 nm laser. The change in stratum corneum hydration after treatment with different humectants was determined from the relative intensity of the water and protein spectra. Raman images were created along a cross section by integrating the Raman intensities for specific vibrational modes. The results show that the hydration profiles of stratum corneum correlates well with the gradient in water chemical potential created by the applied humectants, i.e. low molecular weight humectants enable increased hydration of stratum corneum compared to a high molecular weight, non-penetrating polyethylene glycol. In addition the novel results from the Raman imaging experiments illustrate that it is possible to distinguish between water rich domains and the extracellular lipid rich domains along a cross section of the intact skin membrane.

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P1:2 Monday 3 Sept: Poster presented 18.00-19.00

Cationic ester-containing gemini surfactants: adsorption at tailor-made surfaces monitored by SPR and QCM Tehrani-Bagha Ali Reza ; Krister Holmberg Chalmers University of Technology, Göteborg, Sweden

Adsorption of a series of ester-containing cationic surfactants at a surface containing 90% methyl groups and 10% carboxyl groups was studied by two surface analysis techniques, surface plasmon resonance (SPR) and quartz crystal microbalance (QCM). Such a surface, which is at the same time hydrophobic and negatively charged, is of interest as a model for many polymeric surfaces. Two different types of ester gemini surfactants and their monomeric counterparts were included together with nonester containing surfactants of similar structure. The results show that the Gemini surfactants give the same adsorbed amount at the surface as the monomeric surfactants when compared at the same bulk concentration normalized to the critical micelle concentration (cmc) in bulk. Since the cmc of the geminis is around 20 times lower than the cmc of the corresponding monomeric surfactants, the gemini surfactants are much more effective in covering the surface. The two techniques gave similar relative values but the QCM values were always higher than those from SPR, which is due to the former method taking also adsorbed water into account. The adsorption, as measured by both methods, was found to follow closely the Langmuir adsorption model.

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Coupling of self-propelled motion and division of oil droplets driven by acetal formation Taisuke Banno ; Rie Kuroha ; Taro Toyota Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan

Recently, self-propelled oil droplets in a non-equilibrium system have drawn much attention as a primitive type of inanimate chemical machinery. However, the self-propelled oil droplets gradually stop within several minutes. Thus there is no report of self-propelled motion coupled with other animate elemental characteristics such as self-division. Here we demonstrated a novel system of coupling of self-propelled motion and self-division of oil droplet induced by a chemical conversion of the components. Varying the molar ratio of n-heptyloxybenzaldehyde (HBA) and 1-decylalcohol (DA) from 10/0 to 0/10, we observed the coupled dynamics of oil droplets at the molar ratio of 7/3 reproducibly in a cationic surfactant solution (50 mM) containing 0.01 M HCl. At this condition, the acetal was produced by the reaction of HBA and DA. We also observed the acetal oil droplets were not immediately self-propelled, and then several of them started to move after the induction time of 3 min. Moreover, the acetal was completely hydrolyzed within 1 min and it was not reproduced thereafter in the system. Based on these results, we propose the mechanism of coupled dynamics of the oil droplet as follows. Due to the chemical Marangoni effect and the transfer of molecules around the oil droplet surface, the oil droplets propelled themselves with taking-up additional surfactant and proton from the bulk solution. Therefore the acetal (and hemiacetal) is produced in self-propelled oil droplets. Simultaneously, various molecular aggregates composed of surfactant, oil, and water are gradually formed within the oil droplet. Then, assuming a supersaturation of surfactant, the oil droplet divides because of phase separation. While a droplet composed of HBA and DA can immediately start to move, other smaller droplets float for a while. Because the transformation from acetal (and hemiacetal) to HBA and DA occurs by the acidic hydrolysis in the smaller droplets, they start the self-propelled motion. We thus deduce that the coupled dynamics is owing to the reversible reaction system among aldehyde, alcohol, and acetal (and hemiacetal).

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Self-assembled PNIPAM nanoparticles: specific ion effects Leonor Pérez-Fuentes 1; Carlos Drummond 2; Delfi Bastos-González 1 1University of Granada, Applied Physics, Granada, Spain; 2CNRS, Centre de Recherche Paul Pascal (CRPP), Pessac, France

poly(N-isopropyl acrylamide) (pNIPAM) has attracted considerable interest in the last two decades due to its extraordinary properties of solvency, which are highly dependent on physicochemical conditions such as temperature, salt concentration, and pH. In particular, it has been reported that this polymer becomes water-insoluble when temperature increases (thermally triggered swelling and aggregation). We have shown in the past that pNIPAM lower critical solution temperature (LCST) is very sensitive to ionic specific effects [1]. In this study we exploit this fact to study the origin of ionic specificity, also known as Hofmeister effects. Atomic force Microscopy (AFM) has been used to study the adsorption and swelling-to-collapse transition of cationic and anionic pNIPAM nanoparticles self-assembled on mica. AFM in liquid environment is an excellent tool to sudy in-situ the properties of responsive surfaces [2]. In particular, we have investigated the influence of the type and concentration of ions present in solution on the swelling of the nanoparticles, and the interaction of the self-assembled layers with the AFM tip. We observed that the ionic environment substantially modifies the properties of the adsorbed nanoparticles. The effect of hydrophobic salts, tetraphenil borate sodium and tetraphenil arsonium chloride, was studied in detail, to investigate the connection between hydrophobic and Hofmeister effects [3]. The surface-adsorbed behavior is correlated with the electrokinetic properties of the same particles in solution under identical conditions. [1] T. López-León, A. Elaïssari, J.L. Ortega-Vinuesa and D. Bastos-González ChemPhysChem 2007, 8, 148 [2] Bousquet, A.; Ibarboure, E.; Drummond, C.; Labrugere, C.; Papon, E.; Rodriguez-Hernandez, J. Macromolecules, 2008, 41, 1053 [3] C. Calero, J. Faraudo and D. Bastos-González, J. Am. Chem. Soc. 2011, 113, 15025 Acknowledgements: Authors thank financial support to Spanish Government MAT2009-13155-C04-02 and Junta de Andalucía P10-CTS-0270.

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Temperature-response of γγ-cyclodextrin-PNIPAAM diblock copolymer inclusion complexes at the solid/liquid interface Giuseppe Lazzara 1; Nina Reichardt 2; Solmaz Bayati 2; Richard A. Campbell 3; Kaizheng Zhu 4; Bo Nystrom 4; Tommy Nylander 2; Karin Schillen 2 1University of Palermo, Department of Chemistry, Palermo, Italy; 2Lund University, Division of Physical Chemistry, Lund, Sweden; 3Institut Laue-Langevin, Grenoble, France; 4University of Oslo, Department of Chemistry, Olso, Norway

In the present study, we have investigated the adsorption of the thermoresponsive cationic diblock copolymers of poly(N-isopropylacrylamide) (PNIPAAM) and poly((3-acrylamidopropyl) trimethyl ammonium chloride) (PAMPTMA(+)) PNIPAAMn-b-PAMPTMAm(+) at the silica/water interface, and the effect of the inclusion of the PNIPAAM chains in hollow cyclodextrin (γ-CD) molecules. It has been shown previously that such inclusion complexes form in aqueous solution by threading of γ-CD molecules onto the homopolymer PNIPAAM47 as well as the PNIPAAM block of the PNIPAAM24-b-PAMPTMA9(+) copolymer, see the reference. The bulky cationic block is not incorporated into the CD cavity. A combination of in situ data from null ellipsometry, quartz-crystal microbalance with dissipation monitoring and neutron reflectivity have provided a thorough characterization of the adsorbed amounts, layer thickness, hydration, elasticity, composition and structure of the adsorbed copolymer layer in the absence and presence of γ-CD molecules at temperatures below and above the lower critical solution temperature of PNIPAAM. Reference: Lazzara, G.; Alfredsson, V.; Olofsson, G.; Zhu, K.; Nyström, B.; Schillén, K. Soft Matter 2012, 8, 5043.

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Surface-protein interactions on stainless steel – effects of protein adsorption, surface changes and metal release Yolanda Hedberg ; Xin Wang ; Jonas Hedberg ; Maria Lundin ; Eva Blomberg ; Inger Odnevall Wallinder KTH, Royal Institute of Technology, Dept Chemistry, Div Surface & Corrosion Science, Stockholm, Sweden

Stainless steel (SS) is due to high corrosion resistance properties commonly used in a large variety of applications ranging from outdoor constructions to cooking utensils and biomaterials. The resistance to corrosion is attributed the chromium-rich surface oxide and depends on grade and prevailing environmental conditions. Even though the corrosion resistance is high, alloy components will be released to a certain extent in contact with different media and may induce adverse toxicological effects. In the case of stainless steel, the authors have shown the presence of proteins to enhance the extent of released metals, whereas the opposite situation has been shown for plain carbon steel. In this study the protein induced metal release has been investigated from a kinetic perspective for stainless steel of different microstructural grades in a phosphate buffered saline (PBS, pH 7.4) solution containing either bovine serum albumin (BSA) or lysozyme (LSZ). The results show that both BSA and LSZ induce a significant enrichment of chromium in the surface oxide of all stainless steel grades. The net negatively charged BSA adsorbed in monolayer coverage onto the negatively charged SS surface, whereas the net positively charged LSZ formed thicker layers. Both proteins induced an enhanced extent of released iron, chromium, nickel and manganese, very significant in the case of BSA (up to 40-fold increase), whereas both proteins reduced the corrosion resistance of SS. Generated results are discussed in terms of the influence of bulk composition and structure, surface oxide properties, surface pH, and possible protein-induced metal release mechanisms.

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Understanding the origin of viscoelasticity in cyclodextrin/surfactant films at the air/water interface José Campos-Terán 1; Ángel Piñeiro 2; Richard A. Campbell 3; Jorge Hernández-Pascacio 4; Miguel Costas 4 1Universidad Autónoma Metropolitana-Cuajimalpa, DCNI, Departamento de Procesos y Tecnología, México, Mexico; 2Universidad de Santiago de Compostela, Facultad de Física, Departamento de Física Aplicada, Santiago de Compostela, Spain; 3Institut Laue-Langevin, Grenoble, France; 4Universidad Nacional Autónoma de México, Facultad de Química, Departamento de Fisicoquímica, México, Mexico

Cyclodextrins (CDs) are ring-shaped molecules that are versatile due to their interesting structural, chemical and physicochemical properties. One of the most exploited features of these molecules is their ability to encapsulate hydrophobic groups, increasing their solubility, lowering their volatility and/or protecting them from potential chemical reactions. Spontaneously formed supramolecular aggregates based on these molecules in aqueous solution have been characterized by a number of techniques although much remains to learn. Since aggregation and adsorption to the air/liquid interface are usually coupled processes, we decided to investigate the films produced by these systems at the interface of the solution and discovered that alpha-CDs spontaneously adsorb to air/water interfaces [1] forming films whose mechanical properties can be tuned by the addition of amphiphilic molecules [2]. Indeed the addition of sodium dodecyl sulfate (SDS) at specific concentrations/temperatures increases the viscoelasticity of alpha-CD films by up to two orders of magnitude. Recently we have worked on an experimental campaign to relate the macroscopic viscoelastic properties to the nanoscale film structures. The work is based on the experimental results of neutron reflectometry (NR), ellipsometry (EP), Brewster angle microscopy (BAM), isothermal calorimetry (ITC) and elasticity measurements, plus molecular dynamic simulations. Our results have revealed a highly complex interfacial system possibly involving domains of ordered alpha-CD nanotubes. In particular the interfacial composition from NR combined with the lateral molecular ordering from BAM and bulk compositons from ITC has allowed us to propose a hypothesis for the origin behind the viscoelasticity for the time. The ultimate goal of the project, through understanding the viscoelastic properties for cyclodextrin/surfactant mixtures, is to design functional films. [1] Pineiro, A. et al. J. Phys. Chem. B, 111, 2007, 4383. [2] Hernandez-Pascacio, J. et al. J. Phys. Chem. B, 111, 2007, 12625.

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Resolving complexity of the IC2 autoantibody recognized target on the surface of functional β-cells by QCM affinity measurements Ida Dalgaard Pedersen 1; Kathrine Louise Jensen 1; Camilla Käck 2; Teodor Aastrup 2; Anna Åkesson 3; Marité Cárdenas 3; Karsten Buschard 1; Carl-Henrik Brogren 1 1Rigshospitalet, The Bartholin Institute, Copenhagen, Denmark; 2Attana AB, Stockholm, Sweden; 3University of Copenhagen, Nano-Science Center, Copenhagen, Denmark

Background: Type 1 diabetes mellitus is a chronic disorder resulting from autoimmune destruction of insulin-producing pancreatic β-cells. In advance of clinical symptoms, autoantibodies are produced and self-reactive lymphocytes infiltrate the pancreas to destroy β-cells. A monoclonal autoantibody, IC2, with a unique specificity for functional pancreatic β-cells, was raised from a diabetes-prone BB-rat. As of yet, it has not been possible to reveal the autoantigen giving rise to this unique specificity. To resolve the complexity of the autoantigen, experiments were conducted using quartz crystal microbalance (QCM). Methods: Both cellular and molecular QCM experiments were conducted using the QCM-D E4 and Attana Cell 200. Several IC2 formats were immobilized on quartz crystal chips by different methods e.g. avidin-biotin interaction, bioconjugation by amine coupling, and protein-gold interactions. Affinities were measured to intact INS-1E cells, sonicated plasma membrane vesicles, lipid rafts, lipids, and lipids anchored to the CD1d protein, as well as combinations thereof. In addition different blocking agents were tested in order to reduce unspecific binding. Results: Cellular QCM showed that IC2 has a very strong affinity towards intact INS-1E cells with a dissociation constant of 1.39nM. Several different molecular components were examined by molecular QCM-D. Kinetics were compared and ranked in order to elucidate and resolve the complexity of the IC2 autoantigen. Conclusion: Getting closer to a characterization of the IC2 autoantigen leads to potential new therapeutic approaches with IC2 in drug delivery. These results are also of major importance for the development of IC2 as a functional biomarker for the β-cell mass. This could lead to a characterization of the diabetic process and an improved focus of therapeutic interventions in diabetic patients, by being able to closely follow the effects of treatment with growth promoting drugs and stem-cell therapy.

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Diblock copolymers with a linear cationic block and a non-ionic bottle-brush block: Adsorption, surface and friction forces Per Claesson 1; Xiaoyan Liu 1; Andra Dedinaite 1; Esben Thormann 1; Mark Rutland 1; Ceslav Visnevskij 2; Ricardas Makuska 2 1Royal Institute of Technology, Chemistry / Surface and Corrosion Science, Stockholm, Sweden; 2Vilnius University, Polymer Chemistry, Vilnius, Lithuania

We demonstrate how an extended branched brush layer can be formed by physisorption. This was achieved by employing a diblock copolymer formed by a linear cationic block and a non-ionic bottle-brush block with 45 units long poly(ethylene oxide) side chains. The adsorption properties of the diblock copolymer, as well as of the two blocks separately, were studied on silica surfaces using QCM-D, optical and neutron reflectometry. In agreement with theoretical predictions,[1] it was found that the surface excess was higher than for random copolymers with the same type of segments. The water content of the adsorbed layer was found to be high, above 90%. The kinetic adsorption data highlight that the diblock copolymers initially adsorb preferentially parallel to the surface with both the cationic block and the uncharged bottle-brush block in contact with the surface. However, as the adsorption proceeds a structural change occurs within the layer and the PEO bottle-brush block extends towards solution, forming a surface anchored branched brush layer. The forces acting between two such layers were determined with the AFM colloidal probe technique and found to be dominated by a weak electrostatic repulsion at large separations, and at shorter separations by a strong steric repulsion. The boundary lubrication offered by the adsorbed layers were very favourable, combing a friction force characterized by a friction coefficient of 0.03, a high load bearing capacity of at least 60 MPa in pure water, and a self-healing ability. The importance of the polymer structure and the binding mechanism to the surface for these findings will be discussed. Refernces: 1. Linse, P.; Claesson, P. M., Modeling of bottle-brush polymer adsorption onto mica and silica surfaces. Macromolecules 2009, 42, 6310-6318.

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Interfacial assembly of colloids with a cubic shape Julius de Folter ; Robin Geitenbeek ; Albert Philipse ; Willem Kegel Utrecht University, Physical and Colloid Chemistry, Utrecht, Netherlands

We present the first study of interfacial assembly of colloids with a cubic shape. Particle adsorption at fluid-fluid (e.g. water-oil or water-air) interfaces has proven to be an effective platform to induce 2D self-organization of colloids into larger-scale ordered structures. For instance, colloids can be structured by irreversible adsorption at a macroscopic fluid-fluid interface or can be trapped at the interface of (usually) spherical droplets in so-called Pickering emulsions. Such structures are relevant for example in food, cosmetic, pharmaceutical, petroleum and coating industries. However, most studies to date rely on the interfacial adsorption of spheres. Colloids with anisotropic shapes at interfaces are not only interesting for novel applications, but also allow to address fundamental issues such as particle interactions, orientations, packing densities and their influence on stabilization of emulsions and foams. We have synthesized uniform micron-sized cubes [1] and used them to produce oil-in-water emulsions with the cubes being adsorbed at the oil-water interface. We show that cubes allow for very high packing densities and, using a combination of optical and laser scanning confocal microscopy, we are able to study both the structure as well as the (preferred) orientation of interfacial colloidal cubes on a single particle level. [1] L. Rossi, S. Sacanna, W.T.M. Irvine, P.M. Chaikin, D.J. Pine, and A.P. Philipse, Soft Matter 2011, 7, 4139

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The role of association structures in aqueous lubrication Andra Dedinaite 1; Min Wang 2; Chao Liu 2; Junxue An 2; Esben Thormann 2 1KTH/YKI, Stockholm, Sweden; 2KTH, Stockholm, Sweden

Intricate self-assembly structures are common in both complex artificial and biological liquids, as synovial fluid. These association entities spontaneously arise in bulk and at surfaces due to association of large molecular weight compounds such as synthetic oppositely charged polyelectrolytes and surfactants, and naturally available linear chain polysaccharides, as hyaluronan, mucinous glycoproteins, as mucins and lubricins, and small surface-active molecules, such as phospholipids. When present at the surfaces, they profoundly effect surface interactions. We studied association of small unilamellar dipalmitoylphosphatidyl choline (DPPC) vesicles and hyaluronan in bulk using Dynamic Light Scattering and showed that the association results in vesicles coated with hyaluronan, with little increase in vesicle size and vesicular integrity retained. The Quartz Crystal Microbalance with Dissipation and the LayerLab surface capacitance methodology was employed to characterise layers formed by DPPC vesicles and hyaluronan adsorption on silica surfaces. It was shown that DPPC and hyaluronan adsorb sequentially in several alternating layers, with DPPC building flat stratums in direct contact with silica. The adsorption of hyaluronan is facilitated on such a DPPC layer and we evidence layer consolidation. The Atomic Force Microscope Peak Force and Colloidal Probe techniques have been employed to probe nanomechanical properties and normal and friction forces between silica surfaces coated with these layers.

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Putting a "separation tag" on trivalent lanthanide ions using neutral lipid monolayers and bilayers Thomas Delclos 1; Epameinondas Leontidis 1; Marie-claire Dul 2; Olivier Diat 2; Damien Bourgeois 2 1University of Cyprus (UCY), Chemistry, NICOSIA, Cyprus; 2Institut de Chimie Separative de Marcoule (ICSM), BAGNOLS SUR CEZE, France

A major challenge faced by the nuclear industry is the recycling of spent fuel. The goal of the 4th generation reactors is to recycle fuel efficiently, leaving behind waste with low toxicity. This can be achieved only through extensive recycling, which is a difficult process, since spent fuel contains useful actinides, but also lanthanides and other metal cations that are very difficult to separate from the fuel. The separation from the solution involves classical liquid-liquid extraction steps; these are empirically designed and use non-specific ligands that bind lanthanide and actinide ions, as well as tetravalent ions, and do not extract mono- and divalent ions. Softer interactions are significant in these processes and are poorly understood: the transfer of ions between the extraction phases cannot be represented by molecular equilibria. It has been shown that lipid monolayers can be used to quantitate the affinity of anions for soft matter interfaces, and to assign an interfacial affinity index for each ion. In this work we focus on trivalent lanthanide cations. The method used is based on measurement of surface pressure / molecular area isotherms of lipids in the presence of various concentrations of lanthanide salts (with a Langmuir film balance). The choice of lipids used in this study must rule out strong interactions leading to strong complexation. Therefore we cannot use phospholipids or fatty acids. We have opted to use malonamide and sulfobetaine derivatives with two hydrophobic tails that form more stable Langmuir monolayers. Futhermore, the isotherms of these compounds must be measurably perturbed by lanthanides, preferably in a cation-specific way. In this preliminary study we have screened various parameters such as the ion type and concentration, temperature and pH. The next steps of this project are to use other techniques to obtain complementary thermodynamical data on selected systems. The equipment that will be used for this purpose include PM-IRRAS spectroscopy, ITC, and SPR measurement.

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Mixed PEO/PAA brushes for the control of protein adsorption Marie Delcroix ; Gilles Huet ; Christine Dupont-Gillain Université catholique de Louvain, IMCN/BSMA/SURF, Louvain-la-Neuve, Belgium

Protein-surface interactions may be tailored through the use of smart surfaces, whose properties vary depending on the environment. This can be achieved through the design of mixed polymer brushes. This study aims at creating surfaces showing tunable properties with respect to protein adsorption, using the combination of poly(ethylene oxide) (PEO), a protein-repellent polymer, and of poly(acrylic acid) (PAA), a polymer which adopts different behaviours towards proteins depending on the pH and the ionic strength I. Using an appropriate combination of these two parameters, mixed PEO/PAA brushes are expected to either repel proteins, or allow their immobilization. Brushes of PEO or PAA, as well as mixed brushes synthesized by sequential or simultaneous grafting of both polymers, were successfully assembled on gold using a “grafting to” approach, as was confirmed by water contact angle measurements, atomic force microscopy, X-ray reflectometry, polarisation-modulation reflection-absorption infrared spectroscopy and X-ray photoelectron spectroscopy. Quartz crystal microbalance monitoring showed the swelling/shrinkage of PAA with the modulation of pH and I, in agreement with observations reported in the literature. High amounts of human serum albumin (HSA) were adsorbed on selected mixed brushes at pH in the range of iep of HSA and low I (10-5M). A subsequent rinsing at pH>iepHSA and high I (10-1M) allowed nearly complete desorption of the immobilized proteins. This tunable behaviour could not be observed on homobrushes of PEO, which showed repellency of proteins whatever pH and I, or PAA, where incomplete desorption of proteins was observed. Further experiments with other proteins of different sizes and iep are currently in progress. The designed surfaces showing stimuli-responsive properties with respect to protein adsorption could find applications in biosensor design or biomaterial surface modification.

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Polyhedral oligomeric silsesquioxanes (POSS) in mixed Langmuir monolayers Katarzyna Dopierala 1; Krystyna Prochaska 1; Joanna Karasiewicz 2; Hieronim Maciejewski 2 1Poznan University of Technology, Institute of Chemical Technology and Engineering, Poznan, Poland; 2Adam Mickiewicz University, Department of Chemistry, Poznan, Poland

Polyhedral oligomeric silsesquioxane (POSS) derivatives have recently been reported as a new class of molecules that form stable Langmuir monolayers at the air/water interface and exhibit interesting phase transitions and aggregation behaviour [1-2]. In this study the surface behaviour of POSS molecules has been investigated using KSV Nima Langmuir trough. Mixed monolayers of the amphiphilic heptasubstituted trisilanol-POSS and fully functional octasubstituted molecules have been formed at air/liquid interface. The polyhedral oligomeric silsesquioxanes with various number of groups substituted to SiO cage structure have been analyzed. Compression isotherms as well as isobars (mean molecular area-time dependence at π=const) have been presented to compare surface behaviour of the analyzed compounds. BAM images have shown how morfology of the monolayers changes during the compression, relaxation and expansion. References: [1] J. Deng, J. R. Hottle, J. T. Polidan, H.-J. Kim, C. E. Farmer-Creely, B. D. Viers and A. R. Esker, Langmuir 20, 109-115, (2004) [2] V. A. Ogarev, Colloid Journal, 63,445-452, (2001). The work was financially support by 32-067/12 DS-PB

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Physicochemical characterization of the phosphopeptide/titanium dioxide interaction Anna Eriksson1; Katarina Edwards1; Anders Hagfeldt2; Victor Agmo Hernández1 1Department of Chemistry - BMC, Uppsala, Sweden; 2Department of Chemistry - Ångström, Uppsala, Sweden

One of the most common materials used in the hunt for new phosphoproteomes and signaling pathways is titanium dioxide (TiO2). Thus TiO2 is included in many of the methods for specific phosphopeptide enrichment that are used today (1). However, the physical chemistry leading to the specific enrichment of phosphopeptides on this material is far from completely understood. In this study, we used the quartz crystal microbalance with dissipation monitoring (QCM-D) to analyze how the degree of phosphorylation and the surface roughness of the substrate affect the thermodynamics and kinetics of the phosphopeptide/titanium dioxide interaction. Three different phosphopeptides were used, one mono- (DADE-pY-LIPQQG), one bi- (VLPQDKE-pY-pY-KVKEPGE) and one tri-phosphorylated (TRDI-pY-ETD-pY-pY-RK) peptide. The phosphopeptide affinity was tested on smooth TiO2 and mesoporous (130 and 20 nm particle size) TiO2 surfaces. Our preliminary results show that the adsorption process is slow (a time constant of a few hours) and that the affinity of the phosphoryl group for the substrate increases with the degree of phosphorylation and with surface roughness. (1) Dunn, J. D.; Reid, G. E.; Bruening, M. L., Mass Spectrometry Reviews 2010, 29, (1), 29-54.

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Mechanoresponsive surfaces studied by soft colloidal probe AFM Johann Erath 1; Johanna Bünsow 1; Wilhelm T. S. Huck 2; Andreas Fery 1 1University Bayreuth, Physical Chemistry II, Bayreuth, Germany; 2Radboud University Nijmegen, Institute for Molecules and Materials, Nijmegen, Netherlands

Mechanoresponsive materials convert mechanical stimuli into optical, electrical or chemical signals. In this contribution we show how a mechanically addressable surface with excellent promise for further applications, e.g. bio adhesion studies, can be created on the basis of a cationic, fluorescently labeled polyelectrolyte brush. These surfaces have outstanding properties with pressure sensitivity in the order of (1 kPa) and a lateral resolution better than 1 µm. The experimental setup for studying sensitivity and lateral resolution of these systems is based on the soft colloidal probe technique [1], where a defined force was applied to the brushes using an atomic force microscope (AFM) equipped with a cantilever functionalized with an elastomeric probe. Due to mechanical deformation of the soft colloidal probe the response of the system in the contact area can be monitored with a confocal laser scanning microscope (CLSM) in situ. In order to understand the behavior of the observed response, we model the contact situation underneath the PDMS bead with then JKR-theory developed by Johnson, Kendall and Roberts. We find a decrease in fluorescence intensity (as compared to the background intensity) in areas of compression and a slight increase of fluorescence in areas of tension. Also we could show that the response is stabilized well before acquisition times of 1-2 seconds, is constant over several minutes and is completely reversible. The key advance in the present work [2] is the quantitative characterization of the mechanoresponsive surfaces. We have determined a response function I(p), which correlates local fluorescence intensity (I) to local pressure (p). Beside the basic concept of the technique we will show perspectives for mapping pressure fields in bio-inspired systems. [1] Erath, J.; Schmidt, S.; Fery, A., Soft Matter 6, (2010) 1432. [2] Bünsow, J.; Erath, J.; Biesheuvel, M.; Fery, A.; Huck, W. T. S., Angewandte Chem. Int. Ed., 50, (2011) 9629-9632

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Investigation of opening process of the pores inside hydriphobic membrane under nanofiltration of aqueous-organic mixtures Anatoly Filippov 1; Vladimir Ivanov 1; Alexey Yushkin 2; Alexey Volkov 2 1Gubkin Russian State University of Oil and Gas, Higher Mathematics, Moscow, Russian Federation; 2A.V. Topchiev Institute of Petrochemical Synthesis RAS, Lab of Polymer Membranes, Moscow, Russian Federation

Absence of a liquid flux is observed at small pressure differences during ultra- or nanofiltration of aqueous organic mixtures through hydrophobic membranes. This phenomenon can be explained by necessity of overcoming of the capillary pressure in a membrane pore. Membrane pores having hydrophobic surface are modeled by a set of cylindrical capillaries with different distributed radii. Distribution of dimensionless radii of the membrane pores is supposed to be specified by means of the distribution density which is a relative number of pores of the given radius per unit area of a membrane. Three laws of distribution are considered: (i) normal-logarithmic law, (ii) exponential-power law and (iii) approximate triangular law. The filtration of an aqueous solution of organic substances of different concentration occurs under pressure drop across the membrane. Originally the meniscus, which radius depends on the capillary radius, is formed in each capillary (pore), and the meniscus radius can be defined by a contact angle. We assume the Hagen-Poiseuille law for liquid motion inside membrane pores. Dependence of the liquid flux on pressure difference is nonlinear for small pressure differences, and asymptotically tends to linear law at large pressure differences. Similar behavior of the liquid flux takes place in our experiments with aqueous-spirits mixtures and hydrophobic PMP and PTMSP membranes. So we can describe the behavior of the flux of aqueous-spirits mixtures of different concentrations by varying the membrane pressure drop using our mathematical model without fitting parameters. This work is supported by the Russian Foundation for Basic Research (Grant # 11-08-01043).

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The mutual influence of brine and crude oil composition on interfacial properties of crude oil/brine systems Bartlomiej Gawel ; Caterina Lesaint ; Sulalit Banerjee ; Gisle Oye Norwegian University of Science and Technology (NTNU), Ugelstad Laboratory, Department of Chemical Engineering, Trondheim, Norway

Produced water (PW) is water produced along with crude oil. Most produced waters are more saline than seawater and contain dissolved organic compounds as well as dispersed oil and solids. All of these compounds are potentially harmful for marine flora and fauna if the produced water is discharged directly to the sea. To reduce environmental impact and meet the zero-discharge strategy at the Norwegian Continental Shelf, dispersed oil and dissolved organic compounds must be removed [1]. The removal efficiency of dispersed oil largely depends on oil in water emulsion stability, which can be related to the interfacial tension and interfacial rheology of the films at the oil-water interfaces [2]. Most of the studies are focused on influence of crude oil components and production chemicals on interfacial properties. There is a lack of comprehensive studies which are focused on the mutual role of crude oil and brine components on interfacial film formation, particularly when the ionic strength in the water phase is very high [2] In our studies we investigate the influence of the ion composition at high ionic strength in the water phase and acidic, basic and asphaltenic components in the oil phase on the properties of the interfacial layers. Pendant drop tensiometry has been used in the investigations. A significant role of divalent ions, acidic components and asphaltenes were found. Acidic components suppress the viscoelastic layer formation, likely due to preferential adsorption at the interface. The presence of divalent cations increases interfacial tension, likely due to formation of water soluble complexes. Our results give insight into fundamental processes at oil-water interfaces at ionic strength relevant for produced water treatment processes, which might be a useful tool for the industry in order to increase separation efficiency of dispersed oil. The mechanisms involved will be discussed in details in the full paper. [1] Silset, Anne , Ph.D. Thesis, NTNU, Trondheim, 2008. [2] Sun, H.-Q.; Zhang, L.; Li, Z.-Q.; Zhang, L.; Luo, L.; Zhao, S. Soft Matter, 7, 2011, 7601-7611

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Surface shear rheology of triterpenoid and steroid saponins on the air / water interface Konstantin Golemanov 1; Slavka Tcholakova 2; Nikolai Denkov 2; Edward Pelan 1; Simeon Stoyanov 1 1Unilever Discover R&D, Vlaardingen, Netherlands; 2Sofia University, Department of Chemical Engineering, Sofia, Bulgaria

Saponins are a class of natural surfactants found in more than 500 plant species. They consist of flat hydrophobic head group (triterpenoid or steroid) with hydrophilic polysaccharide chains. According to the number of polysaccharide chains they are classified as monodesmosidic (one chain) or bidesmosidic (two chains). Saponins show a number of positive bio-effects: antimicrobial, anti-inflammatory, cholesterol-lowering etc. Results published in the literature show that some types of saponins exhibit significant surface activity and can form layers at air / water interface with high surface shear or dilatational elasticity. Foams stabilized with surfactants with high surface modulus, G, have higher stability: slower Ostwald ripening and liquid drainage. In this way saponins with high G are desired foam stabilizers both because of their surface properties and their bio-activity (food, pharmaceutical applications). The relation between the structure of the saponin molecules and their surface rheological properties is not well understood. Identifying the particular molecular structure which leads to high G of the adsorption layers, would help in selecting more effective foam stabilizers. Here we study a number of triterpenoid and steroid saponins. We characterized the rheological behavior of the surfactant absorption layers on the air/water interface in steady or oscillatory shear deformation. Triterpenoid saponins contained in the species Sapindus Mukurossi, Camelia Oleifera Abel, Aesculus hippocastanum, Quillaja Saponaria Molina exhibited high surface elasticity. This group includes saponins with one or two sugar residues, or mixtures of the two types (bidesmosidic and monodesmosidic). The saponins differed greatly in respect to the value of the surface modulus. However qualitatively they shared a number of common features in their rheological behavior. All of the studied steroid saponins had low viscosity and no measurable elasticity.

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Removal of protein and mineral based deposit after heat treatment of milk Carin Hagsten 1; Lars Hamberg 1; Niklas Lorén 2; Johan Wiklund 2; Fredrik Innings 3; Lena Nilsson 4; Marie Paulsson 5; Christian Trägårdh 5; Tommy Nylander 6 1SIK - The Swedish Institute for Food and Biotechnology, Process and Technology Development, Gothenburg, Sweden; 2SIK - The Swedish Institute for Food and Biotechnology, Structure and Material Design, Gothenburg, Sweden; 3Tetra Pak Processing Systems, Research & Technology, Lund, Sweden; 4Arla Foods, ASIC, Stockholm, Sweden; 5Lund University, Division of Food Technology, Department of Food Technology, Engineering and Nutrition, Lund, Sweden; 6Lund University, Division of Physical Chemistry, Department of Chemistry, Lund, Sweden

Milk is a highly nutritious food, which is also used as the based for other food products. For human consumption, cow milk represents 84% of the world’s milk consumption (Bulletin of the International Dairy Federation (IDF), the world dairy situation, 2010). In order to provide safe food products, milk is usually pasteurized (72-76°C) in order to destroy viable bacteria, which in the worst case cause spread of disease. For products with prolonged shelf life and decreased need for cold storage, the milk is heated to an elevated temperature, so-called UHT treatment, to kill also thermophile bacteria. While reaching the UHT temperatures (140°C), the denaturation temperature of proteins is also passed and these proteins will therefore unfold, aggregate and deposit onto the heated surfaces. Protein and mineral deposits onto the surface, called fouling, impose difficulties with heat transfer into the milk and can also cause off-flavors. The produced fouling needs to be removed to ensure a safe process. So far fundamental understanding of the mechanisms behind cleaning of different fouling systems, in particular those formed at UHT temperature is lacking, preventing the use of tailored cleaning processes. Such cleaning programs could help save energy, water and chemicals, which would mean big cost savings for the dairy industry. An environmentally safe food process industry would also be one step closer. Our aim is to provide a fundamental understanding of the mechanisms behind industrially relevant cleaning process. For this purpose we have conducted both lab-scale and pilot plant experiments to visualize the processes involved in the cleaning process. Knowledge of the cleaning mechanisms will be provided, by recording data where important parameters for fouling are controlled, starting with the impact of flow and detergent concentration. As a first step a model fouling of whey protein was used, which at a later stage will be replaced by an industrially produced fouling. The measurements are inline and non-invasive, including laser and ultrasonic based techniques, which make it possible to follow the removal as well as structural changes of the fouling over time.

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Controlling the van der Waals force: a CP-AFM study Nicklas Hjalmarsson 1; Rubén Alvarez Asencio 1; Deborah Wakeham 1; Lennart Bergström 2; Adam A. Feiler 3; Mark W. Rutland 1 1Surface and Corrosion Science, KTH-Royal Institute of Technology, Stockholm, Sweden; 2Stockholm University, Stockholm, Sweden; 3YKI, Stockholm, Sweden

A simple and robust means of controlling stiction will be of great importance for developing specialized NEMS – as well as other sliding contacts. Here we demonstrate an approach to controlling the ubiquitous van der Waals force between well-known and established metal oxides. Several authors have shown that the sign of the Hamaker constant will determine the system’s behavior (1-4). The Hamaker constant can be calculated with Lifshitz theory using optical data for the materials involved. A negative Hamaker constant occurs if the dielectric response of the media is intermediate to the two surfaces leading to a net repulsive force. The refractive index of a material can be substituted for the dielectric response to estimate the performance of the system. A smooth hydrophobic silica surface interacts with a hydrophobic Titania bead (28 µm) attached to a tipless cantilever. Our system is alternately immersed in liquids with refractive indices of 1.65 and 1.41 respectively. The force-distance curves show that the interaction can be tuned by controlling the dielectric properties of the liquid, and that this can be performed between low cost, and environmentally acceptable materials. References: 1. Feiler AA, Bergstrom L, Rutland MW. Superlubricity using repulsive van der Waals forces. Langmuir. 2008;24(6):2274-6. 2. Lee SW, Sigmund WM. AFM study of repulsive van der Waals forces between Teflon AF (TM) thin film and silica or alumina. Colloid Surface A. 2002;204(1-3):43-50. 3. Meurk A, Luckham PF, Bergstrom L. Direct measurement of repulsive and attractive van der Waals forces between inorganic materials. Langmuir. 1997;13(14):3896-9. 4. Milling A, Mulvaney P, Larson I. Direct measurement of repulsive van der Waals interactions using an atomic force microscope. J Colloid Interf Sci. 1996;180(2):460-5. Corresponding author: [email protected]

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Self-assembly of amphiphilic block copolymers in solution and close to a surface: a simulation approach Virginie Hugouvieux 1; Monique A. V. Axelos 2; Max Kolb 3 1INRA, UMR1083 SPO, Montpellier, France; 2INRA, UR1268 BIA, Nantes, France; 3Ecole Normale Supérieure, Laboratoire de chimie, Lyon, France

Amphiphilic multiblock copolymers are versatile macromolecules able to form a large variety of structures, both intra- or intermolecular. Applications range from stabilizing, emulsifying or foaming agents to rheology modifiers and drug vectors. In this study we focus on the structures and properties of copolymers with a large number of hydrophobic and hydrophilic blocks, both in solution or close to a surface. For this purpose, we use a lattice Monte Carlo simulation approach. In solution, multiblock copolymers self-assemble because of the hydrophobic effect, which leads to an effective attraction between the hydrophobic blocks. At low concentration they form intramolecular structures ranging from pearl-necklaces of micelles to lamellar structures depending on the quality of the solvent and the ratio of hydrophobic to hydrophilic monomers [1]. At higher concentrations (semi-dilute solutions) intermolecular micelles and percolating networks are observed. The topologies of the networks depend on the hydrophobic content of the copolymers, showing either a weak network of micelles that are loosely connected by hydrophilic blocks or a strong network of hydrophobically connected tubular micelles [2]. In the presence of a solid hydrophobic surface, the hydrophobic blocks tend to adsorb and form isolated surface micelles with a well-defined size whenever bulk micelles are present. With increasing surface hydrophobicity the surface micelles arrange in a regular manner. Surface percolation is favoured by the multiblock nature of the copolymers. Long multiblock copolymers also lead to the presence of a secondary bulk micellar layer attached to the layer of surface micelles. All the observed phenomena, both in solution and at the surface, can be explained by the mechanism of micellisation - a balance between energy and entropy – and by the connectivity of multiblock copolymers. 1. Hugouvieux, V.; Axelos, M. A. V.; Kolb, M. Macromolecules 2009, 42, 392-400. 2. Hugouvieux, V.; Axelos, M. A. V.; Kolb, M. Soft Matter 2011, 7, 2580-2591.

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Remarks on measuring the contact angle of high contact angle, high hysteresis surfaces Tommi Huhtamäki ; Juuso T. Korhonen ; Robin H.A. Ras Aalto University, School of Science, Espoo, Finland

Contact angles are often reported in the literature without specifying which angles they are or how they were measured. Ideally, it would be best to report the most stable contact angle, but due to practical difficulties it may be very hard or impossible to measure [1]. Therefore, both the advancing and the receding angle should be reported to characterize the surface properly. We have a method for preparing samples with varying hysteresis, and have spent considerable effort to characterize their wetting properties in a reliable and reproducible way. Especially the receding angle seems to be difficult to measure [2]. We have found a way to measure both the advancing and receding angles of a high hysteresis surface in a reproducible manner. [1] A. Marmur Soft Matter (2006), 2, 12-17. [2] See e.g. D. Rollings, J. Veinot Langmuir (2008), 24, 13653-13662; Teisala, H., Tuominen, M., et al., Langmuir (2012), 28i, 3138-3145

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Study on the counterion distribution of surfactant adsorbed films by total-reflection XAFS measurement Yosuke Imai 1; Huihui Li 1; Hiroki Takumi 1; Hajime Tanida 2; Iwao Watanabe 3; Takanori Takiue 1; Hiroki Matsubara 1; Makoto Aratono 1 1Kyushu University, Fukuoka, Japan; 2Kyoto University, Kyoto, Japan; 3Ritsumeikan University, Kusatsu, Japan

The total reflection X-ray absorption fine structure measurement was applied to the adsorbed film at the surface of surfactant aqueous solutions for investigating the distribution of counterion Br- in the surface region. For dodecyltrimethylammonium bromide (DTABr) solution, the obtained XAFS spectra were expressed as linear combination of two specific spectra respectively corresponding to the fully hydrated bromide ion (free-Br) and the partially dehydrated bromide ion adsorbed to the hydrophilic group of surfactant ion (bound-Br) at the surface. The ratio of bound-Br ions (bound-ratio) was increased with surface density of surfactant ion. The effect of the mixing of different kinds of counterions on the distribution of Br- ion in the surface region was also examined with respect to the binary surfactant mixtures with common surfactant ion and different counterions such as DTABr-DTACl, DTABr-DTABF4, and 1-hexyl-3-methylimidazolium bromide (HMIMBr)-HMIMBF4. The bound-ratio was determined as a function of the surface composition of counterions. In DTABr-DTACl system, the bound-ratio was almost the same as that of pure DTABr system, that is, the distribution of Br- ion was not altered by the existence of Cl- ions. In DTABr-DTABF4 system, the bound-ratio was lower than that of DTABr system, and preferential binding of BF4

- ions to the surfactant ion was suggested. In HMIMBr-HMIMBF4 system, the preferential binding of BF4

- ions in this system was much stronger and the bound-ratio was almost zero. In this case, all Br- ions are distributed as free-Br ion. It was concluded that the counterion distribution are modified by the differences of the nature of counterions and the specific interaction between counterion and surfactant ion [1,2]. [1] Shimamoto, K. et al., Langmuir, 2009, 25, 9954. [2] Li, H. H. et al., J. Colloid and Interface Sci., 2011, 359, 189.

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Vertical positioning and internal structure of microgel particles at liquid-liquid interfaces Lucio Isa 1; Karen Geisel 2; Walter Richtering 2 1ETH Zurich, Department of Materials, Zurich, Switzerland; 2RWTH Aachen, Institute for Physical Chemistry, Aachen, Germany

Responsive microgels have been recently used as a new class of emulsion stabilizers [1]. These soft, deformable sub-micron crosslinked polymeric hydrogel particles can also show responsive properties (charge, swelling) as a function of pH or temperature. Their use presents advantages compared to rigid particles, e.g. a densely packed compliant shell can avoid coalescence upon severe droplet deformation [2]. Responsiveness can trigger controlled coalescence or droplet rupture for smart delivery applications. Despite the advantages, the mechanisms behind emulsion stability using microgels are still not fully understood. Spatial distribution of charges, partitioning of polar oils inside the porous microgels and microstructure changes at the interface, completely absent for hard particles, play key roles. Such open questions can only be answered by direct visualization of the microgels in situ at the interface. We present here for the first time direct 3D information on the positioning and interface microstructure of microgel particles with nm accuracy at oil-water interfaces by using freeze-fracture, shadow-casting (FreSCa) cryo-SEM [3]. We synthesized pH and thermo-sensitive bare poly-(N-isopropylacrylamide-co-methacrylic acid), PMAA) microgels as well as particles which also have a purely thermo-responsive poly-(N-isopropylacrylamide) shell grafted onto the PMAA cores (P(NiPAM-co-MAA)) [4]. FreSCa cryo-SEM data show that all microgels undergo severe deformation (flattening) and present effective contact angles below 30° at water/heptane interfaces. Surprisingly, we also observed that pH-induced swelling in bulk does not affect the size and wetting properties of the microgels at the interface. This suggests that a balance between interfacial activity of the polymer and internal elasticity dominates the behaviour at liquid interfaces. Extensive experimental characterization and a simple model will be presented. [1] Ngai, T., Behrens, S. H. and Auweter, H., Chem.Comm., 2005, 331 [2] Liu, T. et al., Proc. Natl. Acad. Sci. U.S.A., 2012, 109, 384 [3] Isa L. et al., Nature Communications, 2011, 2:438 [4] Pich, A. and Richtering, W., Adv. Polym. Sci., 2010, 234, 1

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Composite microgel-based fibers and films Dominic Kehren ; Andrij Pich DWI / ITMC RWTH Aachen, Aachen, Germany

Our work and experimental results demonstrate the possibilities to build up composite structures based on temperature sensitive polyvinylcaprolactam (VCL) microgels and polycaprolactone (PCL). Prior to the preparation of the composites we analyzed methanol and toluene (50:50) solutions with microgels and PCL mixed in different ratios. The focus of this investigation was the swelling behavior of the microgels, the rheological properties, the sedimentation behavior and the colloidal stability. The obtained microgel/PCL solutions were used to fabricate microfibers by means of an electrospinning process. SEM investigations show that we obtained micrometer sized PCL fibers with a surface layer of microgel particles that is formed due to phase separation. This microgel-based layer changes the properties of the PCL fibers. In contrast to pure PCL fibers, the ones with microgels on the surface are able to uptake water and release it due to the microgels’ temperature sensitivity. The latter is proven by the volume phase transition investigated by means of DSC and the water uptake by means of TGA. Moreover we were able to show the degradability of the fibers and the release of the microgel particles from this structure. In addition, we used microgel/PCL solutions in methanol and toluene (50:50) to fabricate thin films. For this we used a slow drying process, spin-coating and floating film preparation on water. The achieved films show the microgel particles well arranged on the surface. Water uptake, volume phase transition and degradability for the composite films were investigated similarly to the PCL/microgel fibers. We believe that microgel-based fibres and films can be used for medical applications due to their biocompatibility and degradability, and the microgels present in these composite materials allow a controlled drug uptake and release triggered by temperature or pH. These potential applications provide also an outlook to our future research on this system.

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Complex self-assembly morphologies of multicomponent miktoarm star copolymers Jacob Judas Kain Kirkensgaard University of Copenhagen, Niels Bohr Institute, Copenhagen Ø, Denmark

The self-assembly morphologies of various complex architectured miktoarm star copolymers consisting of more than two components have been investigated using dissipative particle dynamics simulations. The star topology of such molecules allow a wealth of new structures to be controllably realized as a function of composition, interaction parameters and molecular architecture. Here a number of highlights are presented showing many novel kaleidoscopic morphologies, including 2D tiling patters and 3D networks many of which show hierachical features, i.e. ordering on multiple length scales. Several examples are extensions of the well-known bicontinuous structures P, D and G found in many natural and synthetic two-component systems.

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Bacterial adhesion to glass surface. Influence of surface roughness Bohinc Klemen 1; Damijan Nipiè 1; Karmen Godic Torkar 1; Martina Oder 1; Goran Drazic 2; Peter Raspor 3 1Faculty of Health Sciences, University of Ljubljana, Ljubljana, Slovenia; 2Insitut Jožef Stefan, Ljubljana, Slovenia; 3Biotechnical Faculty, Univeristy of Ljubljana, Ljubljana, Slovenia

Interactions between bacteria and material surfaces play an important role in biology and different process technologies. The objective of this study is to investigate the influence of surface roughness on the degree of bacterial adhesion. The surface roughness is adjusted as needed by polishing the glass plates made of borosilicate. The roughness, morphology and texture of the glass surface was measured and evaluated by Atomic force microscopy (AFM) [1]. The adhered cells are stained and detected spectrophotometrically and consequently compared with the results obtained by scanning electron microscopy [2]. The experiments were made with Pseudomonas aeruginosa. Staining of the adhered cells on glass plates shows that adhesion of bacteria P. aeruginosa greatly depends on the surface characteristics. The adhesion capacity increases with increasing roughness of the glass surface. We had been shown that P. aeruginosa better occupy rough surfaces than smooth surfaces. Preliminary results indicate that the bacterial adhesion depends on the surface roughness. [1] Eaton, P.J., West, P. 2010. Atomic Force Microscopy West, Oxford Univesity Press. [2] Franson, T.R., Sheth, N.K., Rose, H. D., Sohnle, P.G., 1984. Scanning electron microscopy of bacteria adherent to intravascular catheters, Journal of Clinical Microbiology, 20(3): 500-505.

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Adsorption-desorption fenomena on surface of aqueous solutions Natalia Kochurova ; Nail Abdulin St.Petersburg University, Chem.Faculty, St.Petersburg, Russian Federation

Dynamic surface tension of solutions of surfactants, nonorganic salts, polimers and their complexes is presented in this work. Surface electrolization was estimated from experiment by means of adsorption equation for nonequilibrium surface layer in which surface tension changes with change of surface electrical potential [1]. These results explane the increase of surface tension of surfactant solution at small surface age and the existance of minimum point on isoterm of the nonorganic salt solution dynamic surface tention. Suppoted by the Grant NSH-4464.2012.3 [1] N.N. Kochurova, N.G. Abdulin, I.A. Tihomirov, I.I. Germasheva. Vestnik SPbGU, Ser.4. 2011.Vip.4 (in Russian)

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Local reversible switching between superhydrophobic states on a post array Tuukka Verho 1; Juuso T. Korhonen 1; Lauri Sainiemi 2; Ville Jokinen 2; Chris Bower 3; Kristian Franze 4; Sami Franssila 2; Piers Andrew 3; Olli Ikkala 1; Robin H. A. Ras 1 1Aalto University, Applied Physics, Molecular Materials, Espoo, Finland; 2Aalto University, Materials Science and Engineering, Espoo, Finland; 3Nokia Research Center, Cambridge, United Kingdom; 4University of Cambridge, Department of Physics, Cambridge, United Kingdom

The ability of the leaf of a lotus to repel water and dirt is well known. The hydrophobicity of the leaf is enhanced by a dual-scale roughness on the leaf surface. We have created dual-scale hierarchically rough post arrays, where the smaller-level roughness is superhydrophobic in itself. For a single-level topography two wetting regimes are expected: the so called Cassie-state, where only the post tops are wetted; and the Wenzel-state, where the whole solid area is wetted. Because of the favourability of wetting, the Wenzel state is usually energetically more stable. For dual-scale topography this is not the case and we identify two Cassie-like states (although more are theoretically possible): a micro-Cassie state, where water-air interface resides over both large- and small-scale roughness; and a nano-Cassie state, where water penetrates into the larger features, but still resides over the small-scale roughness. We show that the micro-Cassie state is energetically favourable and that reversible transitions between these two states can easily be induced. The shape of the water interface can easily be imaged with normal optical microscopy and transition lines can be identified. To further determine the shape of the meniscus, we employed a novel confocal microscopy technique, where fluorescent nanoparticles are dispersed into the liquid phase. Taking micrographs at different heights reveal that air is trapped between the pillars in the micro-Cassie state, but not in the nano-Cassie state. Force balance considerations predict a critical transition pressure, when the micro-Cassie state will change to the nano-Cassie state. Nano-Cassie regions can be easily “drawn” simply with a jet of water from a syringe. Reverse transition to the micro-Cassie state can happen spontaneously or it can be induced by introducing “negative pressure”, i.e. by sucking with the needle. We envision that the stability of the micro-Cassie state could be one of the reasons why the lotus plant has dual-scale roughness on its leaf.

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Molecular dynamic study of tetra-naphtenic acids at water/oil interfaces Karina Kovalchuk 1; Johan Sjöblom 1; Brian Grimes 2 1Norwegian University of Science and Technology, Ugelstad Laboratory, Chemical Engineering, Trondheim, Norway; 2Norwegian University of Science and Technology, Chemical Engineering, Trondheim, Norway

Research problem: The present study addresses the naphthenate deposition problem that is encountered during pressure reduction, where degassing of the carbon dioxide from the production water results in an increased pH and dissociation of naphthenic acids at the water/oil interface followed by reaction with the salt ions in the aqueous phase leading to a precipitation. Goal of present study: Understanding the factors influencing the interfacial organization and composition of tetra-naphthenic acids at the interface as well as understanding the nature of interactions between surfactants in mixed interfacial systems. Methods and results: Molecular dynamic simulations were used to study the adsorption dynamics and interfacial structure (positioning at the interface and interfacial arrangement) of a model compound (BP10) that mimics an indigenous tetra-naphthenic acid, a fatty mono-acid, and mixture of these two surfactants. The present work is mainly focused on determining the molecular parameters such as the area per molecule (A) and the second virial coefficient (B2) of the molecules at the interface. The value of B2 is related to the strength and nature of molecular interactions at the interface which is important when considering complex mixed interfaces. The MD results will be employed to predict the multi-component equilibrium concentration and composition of the interfacial adsorbed compounds through the use of a molecular-thermodynamic equation of state. Other physicochemical aspects such as effect of solvent nature, pH and adsorption dynamics of the model tetra naphthenic acid compound will also be addressed.

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Study of ion adsorption on modified electrodes by direct force measurements Volodymyr Kuznetsov ; Georg Papastavrou University of Bayreuth, Physical Chemistry II, Bayreuth, Germany

Much attention has been devoted to ion adsorption on hydrophobic surfaces in the last years. Recent advances in computer simulation techniques allowed developing a more comprehensive picture on the molecular level. Particular interest received the mechanisms by which interfaces without ionizable groups can acquire charge due to adsorption of ions, in particular hydrophobic interfaces. However, the number of published experimental studies on this topic is rather limited. In the given contribution we provide a picture of interfacial adsorption based on the direct force measurements of the diffuse layer properties of a modified electrode by colloid probe AFM. Ultra-flat gold substrates modified with self-assembled monolayers (SAMs) with different terminating groups served as electrodes. Configured in this way, the experimental setup provides a possibility to tune ion adsorption by externally applied potential. In this study we concentrated on SAMs terminating in non-ionizable functional groups, i.e. methyl- and hydroxyl-groups. Specific adsorption of ions leads to a shift of the potential of zero charge (pzc). This pzc corresponds to the external potential where the modified electrode has no diffuse layer charge. The diffuse layer potential of SAM-modified electrodes upon pH shows that the surface charge originates from specific adsorption of hydronium and hydroxide ions to the surface. While the hydrophilic OH-terminated SAM has no clear affinity towards either of pH-determining species, the hydrophobic CH3-terminated SAM tends to adsorb hydroxide ions. This finding is in agreement with studies by other techniques, such as streaming potential or electrophoretic mobility. The experimental data are compared to a simple model, which includes specific ion adsorption onto the SAMs. A good semi-quantitative agreement with this model has been found. In particular the observed shift of the potential of zero charge can be well explained.

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Performance of enzymatic biofuel cell in cell cultures Peter Lamberg ; Magnus Falk ; Thomas Arnebrant ; Sergey Shleev ; Tautgirdas Ruzgas Malmo University, Biofilms - Research Center for Biointerfaces, Malmo, Sweden

Nanomaterials are applied in different fields of science. In our laboratory we exploit gold nanoparticles (AuNPs) and carbon nanotubes to establish or promote direct electron transfer between redox enzymes and electrode surfaces. By impregnating nanomaterial structures with redox enzymes we produce composites which possess bioelectrocatalytic properties. These composite materials are exploited as electrodes for biosensors and biofuel cells (BFCs). We have demonstrated a number of BFC designs which work in simple buffer solutions as well as in complex human physiological fluids [1-4]. Although the performance of BFC has been shown in different physiological fluids as well as in implanted situations it is still unknown how biological cells or tissue behave (e.g., inflammatory response) in close proximity to BFCs. To investigate the effects of BFC on eukaryotic cells we study BFC performance in cell cultures. In this work we mainly focus on BFC cathode which is made from AuNPs and Myrothecium verrucaria bilirubin oxidase. Our preliminary results indicate that biocathodes do function in cell culture media. Acknowledgement: Financial support from the EC (FP7-NMP-229255) and the Swedish Research Council is acknowledged. References: 1. Coman V., Vaz-Dominguez C., Ludwig R., Harreither W., Haltrich D., De Lacey A., Ruzgas T., Gorton L. and Shleev S. (2008) Physical Chemistry Chemical Physics, 10(40), 6093-6096. 2. Coman V., Ludwig R., Harreither W., Haltrich D., Gorton L., Ruzgas T. and Shleev S. (2010) Fuel Cells, 10(1), 9-16. 3. Wang X, Falk M., Ortiz R., Matsumura H., Bobacka J., Ludwig R., Bergelin M., Gorton L. and Shleev S. (2012) Biosensors and Bioelectronics, 31(1), 219-225. 4. Falk M., Andoralov V., Blum Z., Sotres J, Suyatin D., Ruzgas T., Arnebrant T. and Shleev S. (2012) Biosensors and Bioelectronics, in press.

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Fragrance Encapsulation: Specific interactions control at the oil-water interface Sandrine Le Tirilly 1; Nadege Pantoustier 1; Cecile Monteux 1; Patrick Perrin 1; Stephane Bone 2; Gerry Fuller 3 1Laboratoire de Physico-chimie des Polymères et Milieux Dispersés, UMR 7615, UPMC-CNRS-ESPCI, Paris, France; 2Givaudan France Fragrances SAS, Argenteuil, France; 3Department of Chemical Engineering, Stanford University, Stanford, United States

The purpose of this project is to develop innovative fragrance core-shell microcapsules to enhance the olfactory performance on fabrics.1 The role of such microcapsules is to protect the perfume molecules from environment and to control the fragrance release. Our approach is to adsorb successively polymer layers on the droplets of a primary direct emulsion by a Layer-By-Layer (LBL) process. Structure, permeability and mechanical properties of the capsules are studied. The production of multilayered emulsions by a process of LBL polymers adsorption directly on oil droplets has been achieved and such emulsions are stable. Capsules were observed using cryo-scanning electron microscopy (cryo-SEM). The mechanical properties of the polymer layers have been investigated with two complementary interfacial rheology techniques: both compression and shear interfacial rheology were studied. We first measured dilatational interfacial elastic modulus with a rising drop tensiometer. The LBL process is directly done on a single drop of model oil (dodecane) with a bulk phase exchange cell. We also measured shear interfacial elastic modulus with a double wall-ring shear rheometer.2 The LBL process was done on a planar dodecane/water interface with a bulk phase exchange cell. The dilatational interfacial elastic modulus exhibits values as high as for proteins or colloids and the interface becomes too rigid for this technique. However the shear interfacial elastic modulus, of more than 100 mN/m, higher than for proteins or colloids, confirms the formation of a rigid membrane at the interface. 1. Bone, S., Vautrin, C., Barbesant, V., Truchon, S., Harrison, I., Geffroy, C. Chimia, 65,177, 2011 2. Vandebril, S., Franck, A., Fuller, G.G., Moldenaers, P. & Vermant, J. Rheol Acta, 49, 131, 2010

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Chain length effects on the miscibility and distribution of the counterions at the surface of ionic liquids aqueous solution Huihui Li ; Yosuke Imai ; Takanori Takiue ; Hiroki Matsubara ; Makoto Aratono Kyushu University, Department of Chemistry, Faculty of Sciences,, Fukuoka, Japan

The imidazolium-based ionic liquids act as cationic surfactants in aqueous solution. We have found that counterions significantly influence on the adsorption of 1-hexyl-3-methylimidazolium bromide (CmimBr) -1-hexyl -3-methylimidazolium tetrafluoroborate (C6mimBF4) mixtures at the air/water interface. That is, BF4

- ions form side by side pairs with C6mim+ ion by hydrogen bonding interaction at the Stern layer, but almost all the Br- are locating in the diffuse double layer. In this work, the alkyl chain length effects on the head group-counterion interaction were studied by employing 1-decyl-3-methylimidazolium bromide (C10mimBr)-1-decyl-3-methylimidazolium tetrafluoroborate (C10mimBF4) system. The surface tension of C10mimBr - C10mimBF4 aqueous solution was measured at constant temperature T (298.15 ± 0.05 K) under atmospheric pressure p by varying the total molality and the composition of C10mimBF4 in the bulk solution. To evaluate the miscibility in the adsorbed film, the phase diagram of adsorption was constructed, from which we observed that the composition of Br- was higher than that of the ideal mixing. This is basically understood by the size effect of counterions that the smaller ion Br-, may benefit in the effective packing with lager ion, BF4

-, in the electrical double layer. Moreover, it is said that polarizable anions are also more efficient to stabilize the interfacial layer. Oppositely, the counterions in the C6mimBr-

C6mimBF4 system were less miscible. These finding suggest that as the alkyl side chain of imidazolium ionic liquids becomes longer, the hydrogen bonds between the BF4

- and imidazolium ion becomes weaker. Therefore, the segregated distribution of counterions in the interfacial zone of C6mimBr-C6mimBF4 system is probably weakened when it happens for the C10mimBr-C10mimBF4 system.

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Surface free energy of bare and fluorinated siloxanes: comparing experimental evaluation and dipole moments calculations Daniela Meroni 1; Giuseppe Cappelletti 1; Silvia Ardizzone 1; Michele Ceotto 1; Cinzia Biaggi 2; Maurizio Benaglia 2; Laura Raimondi 2 1Università degli Studi Milano, Dipartimento di Chimica Fisica ed Elettrochimica, Milano, Italy; 2Università degli Studi Milano, Dipartimento di Chimica Organica Industriale, Milano, Italy

The surface free energy (SFE) is a key parameter in evaluating the physico-chemical features of solid surfaces. [1] Studies on the composition, structure and interfacial phenomena of a surface layer of materials are of special importance. Its assessment allows the interpretation of several phenomena, such as adsorption mechanisms and surface wettability behaviors, occurring at solid-liquid and solid-gas interfaces; hence the knowledge of such properties is fundamental for both technological and more fundamental point of view.[2] Here, the surface free energy of three non-fluorinated and three fluorinated siloxanes is evaluated. All siloxanes were synthesized and deposited in thick films onto a glass substrate by spin coating. Experimental static contact angle data elaborated by empirical models (Zisman, EOS, OWRK), together with theoretical dipole moment calculations and wetting envelope (WE) elaborations allow us to predict the wetting behaviors towards the most common solvents. The effect of the addition of fluorinated -CF3 end-groups in imposing the final wetting features of the siloxane films is fully investigated on the grounds of the above mentioned experimental and theoretical investigations. [1] Mahadik, D. B.; Venkateswara Rao, A.; Parvathy Rao, A.; Waghb, P. B.; Ingale, S.V.; Gupta, S. C. J. Colloid Interface Sci. 2011, 356, 298–302; Janssen, D; De Palma, R.; Verlaak, S.; Heremans, P.; Dehaen, W. Thin Solid Films 2006, 515, 1433–1438. [2] Meroni, D.; Ardizzone, S.; Cappelletti, G.; Ceotto, M.; Ratti, M.; Annunziata, R.; Benaglia, M.; Raimondi, L. J. Phys. Chem. C 2011, 115, 18649–18658; Èerne, L; Simonèiè, B.; Željko M.. Appl. Surface Sci. 2008, 254, 6467–6477.

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Roughness influence on the attachment modes of siloxanes on TiO2 surfaces Guido Soliveri 1; Daniela Meroni 1; Giuseppe Cappelletti 1; Rita Annunziata 2; Silvia Ardizzone 1 1Università degli Studi Milano, Dipartimento di Chimica Fisica ed Elettrochimica, Milano, Italy; 2Università degli Studi Milano, Dipartimento di Chimica Organica Industriale, Milano, Italy

The modulation of TiO2 surface properties represents a hot topic in several fields, from biomaterials to photovoltaics, from chemical sensors to microelectronics [1]. These applications show the necessity of a better theoretical comprehension of the role of micro and nanometric roughness in the tailoring of the wettability of this kind of surfaces [2]. Here, we evaluate how different roughness degrees of the TiO2 substrate influence its interaction with functionalizing molecules in siloxanes-TiO2 composites. A sol-gel based procedure is developed for the deposition of smooth and transparent TiO2 layers (rms < 1 nm for 10 x 10 µm2). The resulting materials are characterized by TGA, FT-IR, dynamic contact angle measurements, SEM and AFM. Rough TiO2 films, instead, are obtained from different procedures, such as spin-coating of sol-gel TiO2 nanoparticles. Both smooth and rough films are used as substrates for the chemical vapor deposition of different siloxanes. The composite layers are characterized by AFM, FT-IR, and dynamic contact angle with different solvents. Moreover, the interaction between siloxane molecules and the TiO2 surface is studied by means of CP/MAS NMR and compared to SiO2 substrates, showing the peculiarity of the attachment mode of the siloxane molecules in the two cases. [1] Chen, X.; Mao,S.S. Chem. Rev. 2007, 107, 2891-2959; Paz, Y. Beilstein J. Nanotechnol. 2011, 2, 845-861. [2] Meroni, D.; Ardizzone, S.; Cappelletti, G.; Ceotto, M.; Ratti, M.; Annunziata, R.; Benaglia, M.; Raimondi, L. J. Phys. Chem. C 2011, 115, 18649–18658.

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Effect of surface properties on bubble size of a foam produced in a rotor-stator mixer Eungenie Seguineau de Preval ; Fabrice Ducept ; Gerard Cuvelier ; Samir Mezdour Agroparistech, Massy, France

Foams are very appreciated by the consumers, therefore the food industry is always looking for better approaches to produce these high quality products in a reproducible way. In order to do so, great care must be taken to control the parameters linked to the product formulation and the processing conditions. This is important since these parameters determine two of the key characteristics of a foamed product. The mean bubble size and the bubble size distribution have a direct impact on the texture. The objective of this work is to develop a fundamental link between surfactant adsorption dynamics, interfacial properties, and foaming processes in rotor-stator mixers in order to predict bubble size. Newtonian and shear thinning model foods including a minimum variety of ingredients were prepared and characterized using rheometry. The Newtonian fluids contain glucose syrup to ensure a wide range of viscosities, and foaming agents: either a whey protein isolate (WPI) or sucrose ester (E473), in order to modify their elasticity or surface tensions. The non-Newtonian fluids were composed of guar or xanthan. The effect of surfactant type/concentration and bulk viscosity on the interface properties were evaluated with a drop tensiometer (Tracker-Teclis ITConcept). Foams have been produced on an instrumented industrial rotor-stator mixer (Mondomix). Bubble size distributions were determined by image analysis. Our results showed that surface tension rate decreased with increase in either surfactant concentration or viscosity or both. By fitting the data to the Langmuir adsorption isotherm and a long time approximation to the Ward-Tordai equation, the adsorption parameters and surfactant diffusivities were obtained and discussed for their relevance to predict mean diameter d32.With this information,trends observed in the mean bubble size and bubble size distribution experimental results were explained in terms of the interfacial and rheological properties.This study allows us to describe a relationship, based on dimensional analysis and which correlated the Sauter diameter with the bulk viscosity, the dynamic surface tension and the operating parameters.

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Hydrodynamic boundary layers on rising bubbles as a tool for granulometric separation of fine solids Elena Mileva ; Ljubomir Nikolov Institute of Physical Chemistry, Bulgarian Academy of Sciences, Department of Interfaces and Colloids, Sofia, Bulgaria

Flotation and separation practice shows that fine hydrophilic solids are often drawn into the froth product. The occurrence of this unwanted event in the classical froth flotation has led to the idea of using it for the separation by size of ground materials. The aim of the present study is to relate this phenomenon to the residence time of the particles in the vicinities of the rising bubbles. Dynamic interactions of fine solids with rising bubbles cause perturbations in the background flow field. A procedure for the mathematical modeling of these disturbances is proposed. The initial idea is that the solids lag behind the background bubble-driven flows. The key point is the possibility of classifying the fine entities according to a general criterion, containing parameters of the outer flow. This criterion is modified so as to account for the effects of gravity in the case of heavy species. The basic result is that there exists a range of particle and bubble dimensions for which the capture of the fine solids is optimal.

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Effect of humidity on PEI-CTAB film formation at the air-water interface Tahereh Mokhtari 1; Karen J. Edler 2; Emma Sparr 1 1Lund University, Physical Chemistry, Lund, Sweden; 2University of Bath, Department of Chemistry, Bath, United Kingdom

The effect of humidity on growth and collapse of polyethyleneimine (PEI) and cetyltrimethylammonium bromide (CTAB) film at the air-water interface is investigated using spectroscopic ellipsometry. The PEI-CTAB film forms almost instantaneously, growing to a thickness of a few microns. In the case of low relative humidity (up to 45% RH), the formed film remains stable. However, upon increasing the humidity, the thickness of the film decreases gradually until completely depleted. These results can be explained with a theoretical diffusion model1 where the film formation at the interface is described by the difference in the chemical potential of water between the bulk solution and the ambient atmosphere. (1) C. Åberg, E. Sparr, K. J. Edler, and H. Wennerström, Langmuir, 2009, 25, 12177

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Studying complex nanoparticle self-assembly at liquid interfaces using pendant drop tensiometry and microrheology Adrienne Nelson ; Lucio Isa ; Torben Gillich ; Nicholas D. Spencer ETH Zürich, Laboratory for Surface Science and Technology, Department of Materials Science, Zürich, Switzerland

Trapping at the interface, combined with lateral mobility and the presence of specific interactions, makes self-assembly of colloidal particles at liquid-liquid interfaces (SALI) a process with huge potential for the creation of controlled structures, including novel ultrathin membranes and capsules. It has recently been demonstrated in our group that superparamagnetic iron oxide nanoparticles (NPs) stabilized by low molecular weight poly(ethylene glycol) (PEG) shells [1,2], can indeed be self-assembled into saturated monolayers at the water/n-decane interface [3,4]. Understanding the basics of SALI is a keystone in turning these NP assemblies into composite membranes suitable for applications. In particular, measuring the viscoelastic properties of the interfacial assemblies in situ and on the micro-scale is of paramount importance. Characterisation of particles using pendant drop tensiometry and dynamic light scattering has been completed at different concentrations in order to comparte the effects of different PEG shells on the behaviour of the particles. Measurements have been carried out on particles stabilised with different molecular weight and architecture (linear versus dendritic) PEG. Particles with longer linear PEG chains show the highest surface activity and the fastest kinetics of adsorption. To further investigate the behaviour of the particle at the decane-water interface, an interfacial microrheology [5] set-up will be used, allowing the tracking of fluorescent tracer particles at the interface by means of a confocal microscope, to measure the viscoelastic properties of the interface. [1] Esther Amstad et al, Nano Letters 9 (2009) 4042–4048. [2] Torben Gillich, PhD Thesis, ETH Zürich, 2011. [3] Lucio Isa et al., CHIMIA International Journal for Chemistry 64, no. 3 (2010) 145–149 [4] Lucio Isa et al., Soft Matter 7 (2011) 7663. [5] Francisco Ortegaet al, Current Opinion in Colloid & Interface Science 15 (2010) 237–245.

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Solubilization in aqueous media: mechanism and optimization Viet Nguyen-Kim 1; Ann-Kathrin Marguerre 2; Michael Gradzielski 3 1Technische Universität Berlin/BASF SE, Ludwigshafen, Germany; 2BASF SE, Ludwigshafen, Germany; 3Technische Universität Berlin, Berlin, Germany

The hydrophobicity and consequential poor water solubility of most active pharmaceutical ingredients (API) is a barrier for biomedical applications. Using amphiphilic substances for enhancing solubilization of APIs is a frequently applied method to approach this problem and enable bioavailability. However, only little is known how structural properties of solubilizers influence their specific interaction with the solubilisate. In the pharmaceutical industry, solubilization activity is most commonly examined by 'trial and error'. An understanding of solubilization mechanisms and their causes may allow the design of effective solubilizers in a more systematic and targeted manner. Here we present a novel route towards a more detailed insight into structure-property relationships and mechanisms of solubilization. Thus we combined High-Throughput Screening and analytical methods like SANS, DLS and 2D-NMR spectroscopy to reveal interactions between micelle forming amphiphilic Polymers (e.g. Poloxamers) and APIs. This enables the design of more advanced tailored solubilization systems.

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How do we recognize water and oil through our tactile sense? Yoshimune Nonomura 1; Yuichiro Arashi 1; Takashi Maeno 2 1Yamagata University, Yonezawa, Japan; 2Keio University, Yokohama, Japan

We can easily distinguish water from oils thorough our tactile sense, because of their characteristic tactile feel. Many cosmetic chemists believe that water is the most effective textural control agent. If the physical origin of tactile feel is clarified, it will be useful in designing virtual reality systems as well as food, cosmetics, and textiles. Here, we evaluated the tactile feel when water and silicone oil were applied to various solid substrates.1 It is expected that the feel of water and oil will change with different kinds of substrates, because the frictional properties of a liquid film depend on the surface properties of the solid substrate. In the present psychophysical evaluations, subjects distinguished water and oil through their sense of feel, because the frictional properties of a water film were characteristic. However, it was difficult to distinguish water and silicone oil on a glass substrate only by its feel. Friction evaluation showed that we recognize the liquid as water when the frictional resistance is large and changeable. On a glass substrate, water and silicone oil were not distinguishable, since both had a large frictional resistance. Statistical analysis suggested the contribution of the wettability of solid substrates to their tactile feel. (1) Y. Nonomura, Y. Arashi, T. Maeno, Colloids Surf. B 2009, 73, 80-83.

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Time-resolved measurement of interfacial tension gradient around a self propelled oil droplet using quasi-elastic laser scattering method Shogo Oshima 1; Taro Toyota 2; Tomonori Nomoto 1; Masanori Fujinami 1 1Chiba University, Chiba, Japan; 2The University of Tokyo, Tokyo, Japan

It is well-known that an alcohol droplet causes the spontaneous motion on an aqueous phase, driven by a Marangoni convection which is induced by a surface tension gradient. This system transforms a chemical energy into a kinetic energy under isothermal conditions and it has been proposed as a simple model of biological self-locomotion. On the contrary, the interfacial tension gradient of this system has never been directly measured yet and a lot of numerical analysis has been only carried out. A time-resolved quasi-elastic laser scattering (QELS) method can measure the interfacial tension in a non-contact manner. In this study, the interfacial tension distribution around the alcohol droplet on an aqueous phase has been investigated by QELS and the mechanism of droplet motion is discussed. 50 ml of aqueous phase containing 5.8 vol % hexanol was filled in a channel(21.5 cm x 1.5 cm x 3.0 cm). A partition board was placed at the center of the channel. As soon as 50 µL of a hexanol droplet was added to one side of the channel, it directionally moved to another side and was trapped at the partition board. We measured the surface tension of the aqueous phase forward and backward the trapped droplet simultaneously by QELS. When the alcohol droplet was trapped, the surface tensions forward and backward it were decreased, indicating that more hexanol was absorbed at the interface. And the variation of the surface tension forward it was higher than that backward it. In addition, the interfacial tensions at both sites were unchanged for more than 10 min. Further, we succeeded in the measurement of the surface tension gradient of this system, namely found that a decrease in surface tension was large as it was away from the trapped alcohol droplet. We have proved that the spontaneous motion of the oil droplet is driven by the Marangoni convection induced by the gradient of the surfactant tension around it.

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Electrokinetics on superhydrophobic surfaces Periklis Papadopoulos ; Xu Deng ; Doris Vollmer Max Planck Institute for Polymer Research, Mainz, Germany

The electrokinetic mobilities of dilute aqueous dispersions of negatively charged polystyrene particles on porous hydrophilic and superhydrophobic surfaces are investigated by confocal laser scanning electron microscopy. To separate the relative contributions of electrophoresis and electro-osmosis, the mobilities of particles on a negatively charged hydrophilic, a superhydrophobic and a partially hydrophilized superhydrophobic coating are measured. On a superhydrophobic surface the dispersion is exposed to a large air-water interface. The reduced wall-friction is expected to cause a higher electro-osmotic mobility. On the other hand, the low charge density of a superhydrophobic surface reduces the electro-osmotic mobility. Due to lack of experimental data it is not clear, however, whether the reduced wall-friction or reduced charge density dominate the electrokinetic mobilities. We found an increase of the apparent mobility on a superhydrophobic and partially hydrophilized coating compared to a hydrophilic one [1]. Likely, this is due to suppressed electro-osmosis on the uncharged or weakly charged surfaces, because the electrophoretic and electro-osmotic forces acting on the particles are oppositely oriented. The apparent mobility remained unaltered after hydrophilization the topmost layers of the coating, implying that the charge density is still too low to enhance electro-osmosis. The increased particle mobility on slippy surfaces is caused by an unhindered electrophoresis. [1] P. Papadopoulos, X. Deng, and D. Vollmer, submitted to J. Phys.: Condensed Matter (2012)

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Spontaneous emulsification and dissolution processes of thermotropic liquid crystal compounds in aqueous surfactant solutions Karthik Reddy Peddireddy 1; Shashi Thutupalli 2; Christian Bahr 2; Stephan Herminghaus 2 1Max Planck Institute of Dynamics and Self Organization, Max Planck Institute of Dynamics and Self Organization, Goettingen, Germany; 2Max Planck Institute of Dynamics and Self Organization, Goettingen, Germany

Thermotropic liquid crystals (LCs) are organic liquids which are usually not miscible with aqueous phases. The presence of surfactants enables the generation of LC-in-water and water-in-LC emulsions, provided that sufficient mechanical energy is added to the system; in that respect the LC/water systems behave just as numerous non-LC oil/water systems. We report here our observation that some common LC compounds (such as, e. g., MBBA or members of the nCB series) can undergo a spontaneous emulsification process, running without addition of mechanical energy, when brought in contact with aqueous surfactant solutions. The details of the process and the observed transient structures depend on the type of the LC phase: For nematic phases we observe the formation of aqueous droplets in the nematic bulk phase as well as nematic droplets in the aqueous bulk phase. For smectic phases, transient structures appear which resemble the myelin figures formed by lyotropic lamellar phases in contact with water. Polarizing microscopy and fluorescence microscopy studies are conducted in order to elucidate the mechanism of this possibly new type of spontaneous emulsification.

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Competitive adsorption at the n-heptane-water interface Wendy Tao ; Sarah Glasson ; Geoff Stevens ; Jilska Perera The University of Melbourne, Chemical and Biomolecular Engineering, Victoria, Australia

The interfacial properties of two-phase oil/water systems containing the metal ion extractant, P50 (5-nonyl-2-hydroxybenzaldoxime) and the organic phase modifiers nonylphenol and tridecanol were investigated. The experimental data for the various components were fitted to the Langmuir isotherm. The surface excess and Langmuir equilibrium constant was obtained for each system. The two component system (extractant and modifier) data was fitted to the extended Langmuir adsorption equation. This equation was found to be a suitable for modifier concentrations of 0.01M. At a modifier concentration of 0.05M significant deviations from the model were observed.

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Synthesis and properties of robust raspberry-like particles Nikolay Puretskiy ; Leonid Ionov Leibniz Institute of Polymer Research Dresden, Nanostructured Materials, Dresden, Germany

Design of materials with superhydrophobic properties is highly important for coating technology, biotechnology, medicine. Successful design of superhydrophobic surfaces requires, however, accurate control of roughness and intrinsic hydrophobicity of material. This can be achieved, for example, using raspberry-like colloidal particles. Unfortunately most of methods for fabrication are unable to provide proper mechanical and chemical stability to the raspberry-like structures particles due to either weak linkage between the particles or solubility of components, such as polystyrene latexes, in organic solvents. We demonstrated synthesis of chemically and mechanically robust raspberry-like particles as well as wetting properties of coatings based on them. The raspberry-like particles were prepared by immobilization of silica nanoparticles on the surface of silica microparticles coated by poly(glycidyl methacrylate) brush layer. The raspberry-like particles retain their structure after ultrasonication and exposure to organic solvents that allows their use as substrates for immobilization on polymers. Fabrication ultrahydrophobic surfaces using raspberry-like particles with immobilized polypentafluorostyrene was also demonstrated [1]. [1] N. Puretskiy and L. Ionov; Langmuir 2011, 27, 3006 – 3011

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Enantioselective adsorption of profen enantiomers on a chiral adsorbent with grafted eremomycin antibiotic Elena Reshetova Institute of Technical Chemistry of Ural Branch of the Russian Academy of Sciences, Laboratory Oxidizing Catalysis in Molten Electrolytes, Perm, Russian Federation

2-Arylpropionic acids (profens) represent an important class of non-steroidal anti-inflammatory drugs (NSAIDs), with analgesic, anti-inflammatory, and antipyretic properties. It is known that only the (S)(+)-form of the NSAIDs is biologically active, while the (R)(−)-form is therapeutically inactive or partially converted to the (S)(+)- form. The inversion to the (S)(+)-form and possible toxic effect associated with this process turned attention to the production of optically pure compounds and control of final purity. The effect of ionic composition of mobile phase on retention and chromatographic separation of optical isomers of several derivatives of 2-arylpropanoic acid (ibuprofen, ketoprofen, naproxen, flurbiprofen) on a chiral stationary phase Diaspher-Chiralsel-E with a grafted eremomycin antibiotic was studied. The experiments were performed on an Agilent 1100 chromatograph equipped with a precision pump, diode-matrix detector, autosampler, and chromatographic oven. As was shown, the mechanism of retention differs from that for hydrophobic reverse-phase adsorbents, as it involves a substantial ion-exchange component that determines the nonmonotonic dependence of the retention factor and the enantioselectivity on eluent pH. Analysis of thermodynamical data shows that for all the compounds under study, adsorption is an enthalpy-controlled process. Structural transformations in the system reflected in the value of the change in entropy prevent the transfer of analyte on the surface of adsorbent (TΔS < 0 ). Upon a rise in the concentration of buffer salt, however, the relative contribution from the entropy component to the Gibbs energy of adsorption increases. The effect of the concentration of buffer salt in the eluent on the chromatography of this class of compounds is discussed. The work was supported by the Russian Foundation for Basic Research, project no. 10-03-00048-a.

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Langmuir films of N-alkanoyl amino acids Lorand Romanszki ; Judit Telegdi ; Lajos Nyikos Research Centre for Natural Sciences, Hungarian Academy of Sciences, Department of Interfaces and Surface Modification, Institute of Materials and Environmental Chemistry, Budapest, Hungary

N-alkanoyl amino acids are compounds interesting because of their potential application in corrosion inhibitor formulas. The corrosion inhibitor efficiency of the water soluble compounds bearing relatively short N-alkanoyl chain length has been found to depend markedly on the i) nature of the base amino acid; ii) nature and length of the α-side chain; iii) length of the N-alkanoyl chain; and iv) the relation of these latter two chain lengths. In our experiments, Langmuir films of water-insoluble compounds with longer N-alkanoyl chains have been investigated. Derivatives of four different amino acids (Ala, Glu, Ser and Phe) in both L and D enantiopure form as well as racemic mixture have been studied. The N-alkanoyl chains on each amino acid base structure were of two different lengths, 16 and 18 carbon atoms respectively. Langmuir films were formed on pure water, as well as on subphases containing different cations and/or pure amino acid enantiomers. These monolayers have been characterized by their Πc collapse pressure, Ac molecular area at collapse point, A0 molecular area extrapolated to zero surface pressure and the difference of the latter two. The formation and evolution of the films was followed by Brewster angle microscope. Acknowledgement: The research leading to these results has received funding from the European Community's Sixth and Seventh Framework Programmes under grant agreement numbers 512161/2004 and 238579/2009.

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Silicon nanowires: fabrication and biofilm formation Juan M. Ruso 1; Natalia Hassan 2; Valeria Verdinelli 3; Paula V. Messina 3 1University of Santiago de Compostela, Applied Physics, Santiago de Compostela, Spain; 2Université Pierre et Marie Curie, Laboratoire Physico-chimie des Electrolytes, Colloides et Sciences Analytiques (PECSA), Paris, France; 3Universidad Nacional del Sur, INQUISUR-CONICET, Department of Chemistry, Bahia Blanca, Argentina

Silica-based nanomaterials are of great interest because of their potential applications in technical and biological devices. Here we first report the use of a microemulsion droplet system as a simple and controllable route for the synthesis of opals-CT materials with and unusual microstructure and interesting optoelectronic characteristics. Very long fibrils of 30-50 nm diameter and more than 20 µm length showing simultaneous short and long wavelength light emissions. Then, thinking in the future use of Si-nanofibers in three-dimensional, 3D, scaffolds for the construction of implantable artificial devices, the correlation among the material surface characteristics and the amount, structure and distribution of adsorbed fibrinogen (Fb) molecules was analyzed. The Fb adsorption process on the Si-nanofibers occurs in a stepwise fashion with an initial rapid adsorption, an intermediate reorganization and finally a second slower adsorption regime over a longer time period. There was a partial protein desorption after the first adsorption process, which demonstrate that this step is reversible until the first 104 seconds. Nevertheless the whole process is irreversible with a high distortion of the original material morphology. The fibrous structure and the similarity in size between the fibrillar substrate and the Fb molecules are proposed to be the key for the adsorption enhanced process and the final acquired material topography.

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Formation of miniaturized patterns at soft interfaces Jayati Sarkar Indian Institute of Technology Delhi, India, Chemical Engineering, New Delhi, India

In recent past we have seen that instabilities in soft thin elastic films (shear modulus <1 MPa) in contact proximity with an external contactor (< 50 nm separation distance) have gained much importance because of their ability to produce features at short-wave range (~thickness of the film (h)). These occur due to a competition between the destabilizing interaction energy present between the contactor and the film and the restoring elastic energy. The present study finds way to fabricate miniaturized instability patterns at such soft interfaces at even smaller length scales. In the first route patterned substrates are used instead of flat ones. Since these instabilities are directly proportional to the thickness of the film, the intriguing question is to find what happens now since the film now has a varying thickness throughout the length. A linear stability analysis suggests that increasing roughness by enhancing the substrate-amplitude produces increasingly smaller instability length-scales. The smallest wavelengths obtainable are 0.3*h. Instability length-scales are found to be largely independent of substrate length-scales. For van der Waals interaction, increase in substrate roughness increases energy penalty to engender instabilities. When externally controllable long-range electric field is employed instead, instabilities can be initiated at very low critical voltages (~32 V) even in relatively stiff films, making it a more suitable route to produce miniaturized instability patterns. In the second route it is seen that in an elastic bi-layer if the bottom layer is made very thin (< 100 nm), the interaction present between the bottom layer and the substrate is strong enough to create a squeezing mode of instability in the elastic bi-layer. This leads to phenomena like delamination and formation of variable miniaturized lengths scales depending on whether the adhesive top film or the wetting bottom film behaves as the compliant dominant one.

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How does a soap film burst during generation? Laurie Saulnier ; Frederic Restagno ; Dominique Langevin ; Emmanuelle Rio Laboratoire de Physique des Solides, CNRS & Université Paris-Sud 11, Orsay, France

Foams are dispersions of gas bubbles in a liquid matrix, stabilized by surface active agents. Their wide range of properties makes them common industrial products. They are not only difficult to generate but also highly unstable. One of the fundamental issues, not fully resolved, is the understanding and control of their stability. We chose to first study a simplified system: the rupture of thin films during their generation. Indeed, so far, the coalescence of soap films has been mostly studied in static conditions, whereas the understanding of their dynamic rupture is crucial to explain foaming properties. To understand the influence of physical-chemistry, we chose to study a non-ionic surfactant (no adsorption barriers) Hexaoxyethylene dodecyl ether (C12E6). We have built an experiment, in which we determine simultaneously the velocity of a frame pulled out a C12E6 solution and the entire shape of the liquid film. We found that the film is made of two parts: the bottom part is of uniform and stationary thickness, well described by the Frankel’s law [Mysels, 1959]; whereas in the top part, the film drains until a black film appears near the frame upper boundary. In this study we characterize both part of the film. We show that the Frankel law breaks down at high capillary number due to surfactants confinement [Saulnier, 2011], and investigate the impact of physical-chemistry and velocity of generation on the spontaneous aperture of a hole in the black film. References K. J. Mysels, K. Shinoda and S. Frankel, Pergamon, New York, 1959. L. Saulnier, F. Restagno, D. Langevin and E. Rio, Langmuir, 27:13406-13409, 2011.

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Cleanability of textile materials in liquid CO2 Victoria Dutschk 1; Stevia Sutanto 2; Alfredo Calvimontes 3 1University of Twente, Engineering of Fibrous Smart Materials, Enschede, Netherlands; 2Delft University of Technology, Process and Energy, Delft, Netherlands; 3Leibniz-Institut für Polymerforschung Dresden e.V., Dresden, Germany

Perchloroethylene (PER) is commonly used as cleaning solvent in the textile dry cleaning industry. Unfortunately, this chemical is toxic, potentially carcinogenic, and harmful for the environment. One of the potential PER alternatives is high pressure carbon dioxide (CO2), which is non-toxic, cheap, and widely available. In the experiments, several types of soiled textiles – cotton, polyester and wool – were cleaned using a 1 L CO2 dry cleaning set-up. Cleanability of these well-characterised textile materials in liquid CO2 was systematically investigated under different process conditions. In addition, by using optical roughness analysis, some topographical changes in the fabric structure after cleaning were studied. It was found that the soil removal, which was represented with the soiling additional density (SAD), strongly depended on the kind of investigated textile materials. The use of a commercial detergent ClipCOO significantly improved the cleanability of all textile materials under study and slightly reduced the re-deposition of soil in the case of wool fabric.

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Antibody-antigen interaction on polystyrene: an in situ ellipsometric study Olof Svensson 1; Thomas Arnebrant 2 1Lund University, Theoretical Chemistry, Lund, Sweden; 2Malmö University, Faculty of Health and Society, Malmö, Sweden

For diagnostic purposes antibodies are frequently immobilized on different types of plastic surfaces such as polystyrene. Despite the widespread use of these types of substrates little is still known about the binding kinetics and structure of the immobilized antibody layer. The objective of this investigation was therefore to elucidate the possibilities of using ellipsometry to monitor the adsorption. This is an optical technique and from the detected changes in polarization of light both the adsorbed amount and thickness of protein layers can be determined in situ with a time resolution of a few seconds. Commercial polystyrene slides used for solid state diagnostics were selected as substrates and the adsorption of three different antibodies (human IgG, bovine IgG and goat anti-human IgG) was evaluated [1]. Experimental results showed that the properties of the adsorbed layers formed were rather similar for the investigated antibodies. The adsorbed amount obtained was 2.0–2.3 mg/m2 with a corresponding thickness of 10–16 nm. It was furthermore found that the antibodies bound irreversibly with respect to rinsing with protein-free solutions. In additional experiments, the consecutive incubation of anti-human IgG and human IgG (and vice versa) was investigated. These results showed that, on average, approximately half of the surface immobilized anti-human IgG molecules are capable of binding to human IgG during incubation. From the consecutive binding experiments it could also be concluded that antibodies present in the polyclonal anti-human IgG preparation were capable of binding to around four different epitopes on the human IgG. [1] Svensson, O.; Arnebrant T. J. Colloid Interface Sci. 2012, 368, 533

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Effect of hydrogen bonding between 1-hexyl-3-methylimidazolium and tetrafluoroborate on miscibility in the mixed adsorbed film Hiroki Takumi ; Takanori Takiue ; Hiroki Matsubara ; Makoto Aratono Kyushu University, Chemistry, Fukuoka, Japan

We have previously showed that the surface pressure of the adsorbed film of 1-hexyl-3-methylimidazolium tetrafluoroborate (C6mimBF4) increases rapidly at the area per molecule very close to the sum of the cross sectional areas of C6mim+ and BF4-. Judging from this result, it was concluded that these ions occupy at the same level of the surface probably due to the hydrogen bonding between them as observed also in the neat ionic liquid surface. In this study, we have investigated the mixing of other surface active components in the adsorbed film of C6mimBF4 with (1) 1-buthanol (C4OH), (2) 1-hexyl-3-methylimidazolium bromide (C6mimBr), and (3) 1-hexylpyridinium tetrafluoroborate (C6PyBF4). To construct the phase diagrams of adsorption, the surface tension was measured as a function of the total molality and composition of the second components at 298.15 K. The obtained phase diagrams showed the positive azeotrope in (1), positive deviation in (2), and ideal mixing in (3), respectively. The positive azeotrope indicates that the C4OH molecules tend to be excluded to the bulk phase due to the formation of hydrogen bond network between C6mim+ and BF4- ions. This tendency becomes weaker for C6mimBF4- C6mimBr mixture because of the entropic contribution of the mixing of counterions in the electrical double layer. The ideal mixing of C6mimBF4- C6PyBF4 suggests that C6Py+ can form hydrogen bond with BF4- similarly to C6mim+. The side-by-side arrangement between C6Py+ and BF4- was also confirmed by examining the surface pressure vs. occupied area curve. However, it is still unclear that which cations interact more strongly with BF4- . To investigate this issue, we are performing the surface tension measurement of C6PyBF4- C4OH mixed system.

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Time-resolved measurement of surface tension of chemical wave in BZ reaction Ryo Tanaka 1; Taro Toyota 2; Tomonori Nomoto 1; Hiroyuki Kitahata 1; Masanori Fujinami 1 1Chiba University, Chiba, Japan; 2The University of Tokyo, Tokyo, Japan

The Belouzov-Zhabotinsky (BZ) reaction is one of the most famous oscillatory chemical systems induced by the oxidative reaction of organic substrates. As the typical reaction example, it has been reported that the surface tension of reaction solution oscillates in a series of the stirred BZ reaction system catalyzed by ferroin and is synchronized with the oscillation of the redox potential of the solution. In this study, we have employed a time-resolved quasi elastic laser scattering (QELS) method, which can measure interfacial tension in a non-contact manner, and carried out the time-resolved measurement of surface tension of the chemical wave of the BZ reaction solution in order to clarify the chemical oscillation mechanism. The ferroin-catalyzed BZ reaction solution was prepared and filled into a petri dish. As soon as a chemical wave generated under the unstirred condition, a laser (980 nm, 200 mW) as an incident light was irradiated at the liquid/air interface through a slit. The scattered light from surface was detected and the surface tension was calculated from its frequency. Two kinds of characteristic variations were observed when the solution containing 6 mM ferroin; the long-term (10 min) monotonic decrease and the oscillation of surface tension with 2 min interval. The former may be caused by adsorption of the bromomoronic acid to the surface. It was, on the contrary, found that the oscillation of surface tension was almost synchronized with the periodic propagation of chemical wave. It was, therefore, concluded that the oscillation of surface tension was synchronized with the oxidation-reduction reaction. Furthermore, the oscillation amplitude was not constant, as compared with the stirred BZ reaction. It is considered that the dynamics of adsorption and desorption of ferroin is inhomogeneous at the chemical wave in the unstirred BZ reaction.

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A thermodynamic study on the condensed film formation of cationic surfactant at oil / water interface Yuhei Tokiwa ; Eisuke Ohtomi ; Yuichi Kitahara ; Takanori Takiue ; Makoto Aratono ; Hiroki Matsubara Kyushu University, Chemistry, Hukuoka, Japan

In general, ionic surfactants do not form condensed film due to electrostatic repulsion between head groups. However, when small amount of alkane is added on the surfactant solution surface, the condensed monolayer is formed upon cooling due to the penetration of alkane molecules into the adsorbed film. In this study, we examined the condensed film formation of hexadecyltrimethylammonium bromide (HTAB) at the oil / water interface. Intermolecular interaction between alkane and surfactant in the adsorbed film was considered by changing the ratio of tetradecane (C14) to hexadecane (C16) in the oil phase. The interfacial tension was measured as a function of temperature T, molality of HTAB in the aqueous solution m and mole fraction of C16 x2. The ellipsometric measurement was also performed to determine the state of the adsorbed film. From the break point of the interfacial tension γ vs. T curve and the discontinuous change of the coefficient of ellipticity ρ, we concluded that the phase transition from expanded to condensed films occurred in the HTAB-C14 system. In the HTAB-C16 system, the same phase transition was not observed due to the freezing of bulk oil. However, it was revealed that the film composition of C16 is larger than that of C14 in the condensed film indicating that the combination of alkane and surfactant with the same chain length is favorable for the condensed film formation. We have also examined the correlation between these phase transitions and the stability of emulsion by varying temperature.

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Preferential adsorption of ions to hydrophobic and polar surfaces studied by vibrational sum frequency spectroscopy Eric Tyrode KTH Royal Institute of Technology, Surface Chemistry, Stockholm, Sweden

Vibrational Sum Frequency Spectroscopy (VSFS) has been used to study the preferential adsorption of a series of ions to hydrophobic and polar uncharged surfaces. Ion enrichment is determined indirectly by targeting surface water vibrational modes. Nonetheless, selected polyatomic ions could also be directly detected. Interfacial water molecules are affected by the presence of ions in mainly two distinct ways. First, their hydrogen bond strength, coordination, and orientation are modified when locally participating in the ion hydration shells. Second, surface electric fields generated by non-monotonic ion profiles induce a preferential orientation of the water dipoles that may extend several molecular layers. VSFS proves to be highly sensitive to both such cases. Ions were classified depending on their propensity to adsorb to both interfaces and found to closely follow the Hofmeister series. The mechanism of adsorption was found however, to display radical differences between the two interfaces.

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Probing the protic ionic liquid surface using x-ray reflectivity Deborah Wakeham 1; Andrew Nelson 2; Gregory G Warr 3; Rob Atkin 1 1The University of Newcastle, Centre for Organic Electronics, Callaghan, Australia; 2Australian Nuclear Science and Technology Organisation, Bragg Institute, Menai, Australia; 3The University of Sydney, School of Chemistry, Sydney, Australia

Ionic liquids are attracting increased research interest across many areas because their physical properties can be controlled through systematic variation in the molecular structure of the cation and anion. In this work the structure of the liquid surface of three protic ionic liquids, ethylammonium nitrate (EAN), propylammonium nitrate (PAN), and ethylammonium formate (EAF), has been elucidated using x—ray reflectivity. The results show all three liquids have an extended interfacial region which can be divided into two parts. The most pronounced structure is observed for PAN, driven by strong solvophobic interactions, while reduced hydrogen bonding in EAF results in the least structured and least extensive interfacial region. The results also suggest a possible reason for the low vapour pressure of ionic liquids.

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Wetting of solid surfaces by bicontinuous microemulsions Stefan Wellert 1; Samantha Micciulla 1; Roland Steitz 2; Thomas Hellweg 3; Regine von Klitzing 1 1TU Berlin, Berlin, Germany; 2Helmholtz Center Berlin, Berlin, Germany; 3University of Bielefeld, Bielefeld, Germany

The increasing use of bio-inspired surfactants in microemulsions leads to the renewed interest in these thermodynamically stable self-assembled structures of oil, water and amphiphiles. Although the interaction between such microemulsions and solid surfaces is essential for many desired functionalities, only few is known about local structure and dynamics of a microemulsion in the vicinity of a solid surface. In particular, the influence of surface hydrophobicity, surfactant adsorption, bending elasticity of the amphiphilic interface and related properties have to be investigated. We used different methods to investigate the interaction of microemulsions with solid surfaces. Measurements of wetting properties at hydrophilic, partially hydrophobic and hydrophobic surfaces were combined with scattering techniques like neutron reflectometry and grazing incidence neutron spin-echo spectroscopy resolving structure and dynamics of the microemulsion at the various solid surfaces. The resulting structural parameters and the observed dynamics in the vicinity of surfaces are compared to the corresponding results measured in the bulk phase with the undisturbed volume phase structure.

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Donnan potentials at the interface between aqueous dextran and gelatin solutions Mark Vis ; Hans Tromp ; Albert Philipse ; Ben Erné Utrecht University, Physical and Colloid Chemistry, Utrecht, Netherlands

Aqueous solutions of proteins and polysaccharides have been observed to phase separate at relatively low concentrations. For instance a system of 3.5 wt% dextran (100 kDa) and 3.5 wt% gelatin (fish gelatin, non-gelling at room temperature, 100 kDa) phase separates into macroscopic dextran- and gelatin-rich phases on a timescale of hours. [1] The resulting liquid/liquid interface is peculiar, compared to the better-known water/oil interfaces: there is only one solvent, to which the interface is fully permeable; the interfacial tension is ultralow, on the order of 1 µN/m; [2] and, as we report here, the interface carries a Donnan potential. The interfacial electrostatics result from the fact that gelatin is a protein and carries a net charge, whereas dextran is uncharged. To ensure electroneutrality, the concentration of (counter)ions must be higher in the gelatin-rich phase than in the coexisting dextran-rich phase. This results in an electrical potential difference between the dextran- and gelatin-rich phases, also known as a Donnan potential. [3,4] We will present the first experimental evidence for the existence of such a potential step at the interface between demixed aqueous polymer solutions. Using direct electrochemical measurements, [5] we find Donnan potentials on the order of a few millivolts. This offers several exciting new prospects to control the interface electrostatically, for instance in the preparation of water/water Pickering emulsions. [1] M. W. Edelman, E. van der Linden, E. H. A. de Hoog, and R. H. Tromp, Biomacromolecules 2, 1148–1154 (2001). [2] E. Scholten, R. Tuinier, R. H. Tromp, and H. N. W. Lekkerkerker, Langmuir 18, 2234–2238 (2002). [3] J. Lyklema, Fundamentals of Interface and Colloid Science (Academic Press, New York, 1991). [4] A. P. Philipse and A. Vrij, J. Phys.: Condens. Matter 23, 194106 (2011). [5] M. Rasa, B. H. Erné, B. Zoetekouw, R. van Roij, and A. P. Philipse, J. Phys.: Condens. Matter 17, 2293–2314 (2005).

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Revealing metal-liquid interfaces using a wealth of surface-specific techniques Mary Wood ; Stuart Clarke ; Rebecca Welbourn ; John Davies ; Ali Zarbakhsh University of Cambridge, Chemistry, Cambridge, United Kingdom

The solid-liquid interface, despite encompassing enormously important and wide-ranging applications, remains relatively neglected. With relevance to modelling the surface interactions and consequent efficacy of engine-oil additives, the adsorption behaviour of amines onto iron oxide has been studied, using laboratory-based techniques, such as solution isotherms, along with rather more unusual polarised neutron reflectometry. Neutron reflectometry is an excellent technique for probing the buried and generally inaccessible solid-liquid interface; the reflection profile obtained depends on elemental composition, and, crucially, on the specific isotopes used. This allows the use of ‘contrast-variation’ and ‘contrast-matching’, where the scattering length density of the components present can be altered by selecting appropriate proportions of isotopes. In this way complex scattering from a multicomponent system is simplified and sensitivity to a particular component of interest greatly enhanced. Using several contrasts also provides additional independent data to aid the determination of a unique structural solution. In this project, polarised neutron reflection has been used, which exploits the different scattering of ‘up’ and ‘down’-spin neutrons by magnetic materials such as iron to provide two sets of data for the same interface and thus enhance the structural solution. The adsorption behaviour of hexadecylamine from hexadecane onto iron oxide has been studied using this method, and shows a high affinity for the surface even at low concentrations. The layer thickness was found to be somewhat less than the length of the extended molecule, suggesting that its lengthy alkyl chains sit at a tilt angle to the surface. This work has great future potential; in particular, studies of acid/amine competition and temperature effects on adsorption are underway.

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Photochemical synthesis of amphiphiles in microemulsions Nadja Wulff 1; Reinhard Strey 2 1University of Cologne, Physical Chemistry, Cologne, Germany; 2University of Cologne, Cologne, Germany

In the synthesis of chemicals, it is often difficult to combine hydrophobic and hydrophilic reactants. Either a common often expensive or toxic solvent is needed, or alternatively, polar and non-polar solvents are mixed as a macroemulsion in order to dissolve both the hydrophilic and hydrophobic reactants, and have them react across the mutual interface. However, macroemulsions yield a relatively small interfacial area between hydrophilic and hydrophobic domains, and thus the reaction rate is slow. Microemulsions avoid this drawback due to the inherent enormous interfacial area, which facilitates significantly higher reaction rates. Furthermore, microemulsions allow monitoring the reaction kinetics by observing changes in phase behavior. To demonstrate this we studied the well-known photochemical induced [2+2]cycloaddition (Paternò Büchi reaction) in microemulsions as model reaction. The product of the Paternò Büchi reaction of 1-octene and pyruvic acid is 3 hexyl-2methyloxetane-2-carboxylic acid, which is an amphiphile. As such it influences the phase behavior of the microemulsion system significantly. In particular, we examined the impact of the in-situ synthesized amphiphile on phase behavior and structure as function of reaction time. With increasing UV-irradiation exposure the point of highest efficiency of the surfactant is shifted to lower temperatures and, interestingly, an increase of efficiency was detected at the same time. Hence, the newly created amphiphile acts like an efficient, hydrophobic co-surfactant. We discuss the potential options that this new discovery opens in terms of the ability to exploit the phase behavior of microemulsions and timed UV radiation in order to achieve high yields of specific preferred enantiomers.

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Using of new modified poly(propylene oxide)/poly(ethylene glycol) block and graft copolymers as demulsifier for petroleum crude Hamad Allohedan Surfactant Research chair, Department of Chemistry, College of Science, King Saud University, Riyadh, Saudi Arabia

The present work aims to prepare new water soluble nonionic amphiphilic block and graft copolymers based on hydrophilic poly (ethylene glycol) (PEG) and hydrophobic poly (propylene oxide) (PPO) at ambient temperature and normal atmospheric pressure. In this respect, poly (propylene oxide), PPO, reacted with MA to produce poly (propylene oxide) maleate diester. The produced polymers reacted with PEG having different molecular weights to produce PEG-PPO-PEG block copolymers. On the other hand PPO grafted with different molar ratios of maleic anhydride (MA) in the presence of dibenzoyl peroxide as a radical grafting initiator to produce PPO-MA grafts. The produced grafts were esterfied with different molecular weights of poly (ethylene glycol) momomethyl ether to produce PPO-MA-PEGME nonionic surfactants. The chemical composition and molecular weights of the prepared copolymers were determined from 1HNMR analyses. The surface properties of the prepared surfactants were determined by measuring the surface tension at different temperatures. The prepared nonionic surfactants were evaluated as demulsifiers for water in crude-oil emulsions for different ratios of crude oil and water at 60 °C. The experimental results showed that the dehydration rate of the prepared demulsifiers reached 100% based on demulsifier chemical compositions and concentrations.

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Self-assembled nanotubes by the anthraquinone containing-stimuli responsive molecule: effect of pH and redox state Hande Unsal ; Nihal Aydogan Hacettepe University, Chemical Engineering, Ankara, Turkey

The superior properties of self-assembled lipid nanotubes such as wide variety of applications, high biocompatibility and very simple production procedures cause them to attract much attention. However, the lipid nanotube forming molecules are generally very expensive and hardly synthesized. That’s why the investigation of simpler and cheaper molecules is needed. Additionally, controlled self-assembly and disassembly of the lipid nanotubes by utilizing reversible control of molecular interactions are very important for their usability in special applications. For these reasons, in this study, the AQNH(CH2)10COOH (AQua) molecule is designed and synthesized in order to collect the properties of simpler molecular structure and possibility of being reversibly controlled by utilizing the redox active anthraquinone and pH sensitive carboxylic acid groups. AQua molecule and ethanolamine mixture is found to form self-assembled nanotubes with the diameter range of 110-190 nm, length of 4-9 µm and a constant wall thickness of 22 nm indicating a multilayered wall structure. The nanotubes have helical markings on their surfaces with a pitch angle of 45° with the tube radius meaning that the formation mechanism corresponds to the chiral symmetry breaking model owing to the fact that chiral nanotubes are formed by achiral AQua molecule. The effect of pH on the aggregate structure has been evaluated in the pH range of 9 to 1. The nanotubes dis-assemble at pH’s lower than 5. There are several carboxyl group containing molecules that have been shown to be pH sensitive but with this Aqua molecule, it is possible to obtain reversible formation of tubular structure upon the increase of pH from 3 to 9. Moreover, AQua molecule is a redox active and reduction of AQ is also resulting in the disruption of the aggregates. By applying a simple design strategy, we obtained stimuli responsive molecule where the both pH and redox state can be used to trigger the disruption of the nanotubes.

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Comparison of the surface behavior of novel ion pair surfactant with natural lung surfactant in the presence of fibrinogen Nihal Aydogan ; Gokce Dilli Hacettepe University, Chemical Engineering, Ankara, Turkey

Lung surfactant is a mixture that covers the alveolar surface and plays a critical role in the healthy breathing process. Under certain circumstances, such as presence of fibrinogen (surface active serum protein), the function of that mixture is inhibited and it needs to be replaced. There could be other causes that give rise to dysfunction of lung surfactant. For the treatment of these diseases there are several commercial mixtures used such as Infasurf. Considering the fact that breathing is a rapidly occurring phenomenon, surfactants that will be used should be able to adsorb to interface and lower the interfacial tension to sufficient levels at short times. In this study we investigate the dynamic surface tension behavior of a newly designed surfactant IPL (C43H90NO10+ C8F17O3S-) and the effect of fibrinogen on the adsorption behavior of that molecule and compared our result with the case where Infasurf is used as a model lung surfactant. By using Pendant Drop technique, competitive adsorption of Infasurf+fibrinogen and IPL+fibrinogen have been investigated at the buffer-chloroform interface. It is determined that 130 seconds after the simultaneous injection of Infasurf and fibrinogen, surface tension profile of pure Infasurf is captured. Competitive adsorption of IPL instead of Infasurf is also resulted with similar surface tension change with time is observed except 20 seconds of delay. Similar experiments are repeated by using Langmuir trough. Times for reaching specific equilibrium surface pressures of Infasurf and IPL after injecting them to sub-phase of pre-adsorbed fibrinogen layer are obtained as 8500 and 10 seconds, respectively. These results support the fact that there exist a substantial difference in terms of adsorption rates between IPL and Infasurf, indicating IPL is an effective surfactant. Therefore, this is an important study which can be described as a preparatory work in usage of synthetic surfactants at mortal diseases such as ARDS.

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Lipase action on self-assembled lipid liquid crystalline nanoparticles Debby Chang 1; Tommy Nylander 1; Justas Barauskas 2 1Lund University, Physical Chemistry, Lund, Sweden; 2Malmo University, Biomedical Science, Malmo, Sweden

Lipid digestion in all living organisms are catalyst by a class of hydrolyses called lipase, either acyl-glycerol lipases (for tri-,di- and mono glyceride digestion) or phospholipases (for phospholipid digestion). They are among the most important enzymes in living organisms that hydrolyze water insoluble lipids and fats into other water poorly soluble molecules. The process therefore induces lipid composition changes that in turn affect the lipid nanoparticle changes into other self-assembled aggregates. Thus understanding of the self-assembly lipid structure and the changes in this structure is crucial for understanding their function. In the proposed experiments we use a new bio-mimicking assays based on nonlamellar self-assembled lipid nanoparticles in order to gain fundamental knowledge on lipase catalyzed processes and release mechanisms. The idea is study the enzymatic digestion of lipids- based nanoscale liquid crystalline assemblies, whose are discrete colloidal 50 – 500 nm particles with distinctive internal cubic, hexagonal or sponge liquid crystalline nanostructure, low degree of polydispersity, and long term stability. The potential of these dispersed nanostructure as drug delivery vehicle has recently been highlighted and in fact some formulations are used today for therapeutic purposes. The aim is to follow the enzymatic reaction by probing the liquid crystalline nanoparticle structural changes by SAXS in a minute scale. We show that a combination of SAXS, cryo-TEM and pH-stat titration is very useful to study lipase catalyzed reactions. We have studied time dependent lipase (from Thermomyces lanuginosus) hydrolysis of the glycerol monooleate (GMO)-based cubic liquid crystalline nanoparticles. The results have shown that indeed the lipase induced a sequence of the transformation of the cubic nanoparticles to hexagonal, reversed micellar cubic and finally to reversed micellar solution. We also found that that various impurities in the form of di- and tri-glycerides reduce the lipase activity by almost 10 times when compared to pure GMO.

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Physical chemical study of amino acid-based surfactants Romain Bordes ; Krister Holmberg Chalmers University of Technology, Department of Chemical and Biological Engineering - Applied Chemistry, Gothenburg, Sweden

The release of surfactants in the nature has a dramatic effect on the environment and there is a growing need for the development of new surfactants based on renewable sources, which are in principle carbon dioxide neutral. We have investigated the solution behavior and adsorption at the air-water interface, as well as on a number of solid surfaces of three dicarboxylic amino acid-based surfactants, the disodium salts of dodecylaminomalonic acid, dodecylaspartic acid and dodecylglutamic acid, having one, two and three carbon atoms, respectively between the carboxyl groups. The dicarboxylic surfactants had 4-5 times higher CMC than the monocarboxylic amino acid based surfactant, i.e. the sodium dodecylglycinate. Dodecylglutamate was found to be very calcium tolerant compared to the two other dicarboxylic surfactants, and this was due to differences in chelating the calcium cations. These differences were also noticed for the adsorption at calcium-containing surfaces. Dodecylaminomalonate and, in particular, dodecylaspartate adsorb strongly on hydroxyapatite, while dodecylglutamate shows very weak adsorption. On other type of surface, because of the lack of specific interactions with the surfactant headgroup, no specificity was noticed in the adsorption behavior. Also, the role of the amide bond for the self-assembly process was assessed by comparing two monocarboxylic amino acid based surfactants: the sodium dodecylglycinate with the sodium dodecylsarcosinate. The former can build hydrogen bonds between adjacent molecules via the amide groups but the latter, which has an N-methyl group, cannot. It was found that the ability to form intermolecular hydrogen bonds lead to tighter packing both at the air-water interface and in micelles.

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Nano-liposomes for the encapsulation of food preservatives Clotilde Bouaoud 1; Jérôme G.J.L. Lebouille 2; Gabrie M.H. Meesters 1; Remco Tuinier 3 1DSM Biotechnology Center, DownStream Processing, Delft, Netherlands; 2DSM Research, Advance Chemical Engineering Solutions, Geleen, Netherlands; 3Van't Hoff Laboratory for Physical and Colloid Chemistry, Debye Institute, Utrecht University, Utrecht, Netherlands

Preservation of food surfaces to avoid contamination by micro-organisms is a recurring concern of the food industry. Protection can be obtained by applying on food surfaces coatings containing particles of poorly water-soluble preservative ingredients. However, these preservatives are often degraded through unfavourable environmental factors and loose their efficiency. Encapsulation systems able to protect the preservatives from degradation and possibly to provide a controlled release of these compounds are nowadays highly desired by the food industry. Among the possibilities, liposomes [1] are of great interest due to their food-grade components, their versatility and their ability to entrap a great variety of molecules. In this work, nano-liposomes were prepared from commercial soybean lecithins using the “nano-precipitation” method developed by Fessi [2]. The formation of a colloidal suspension of nano-liposomes was obtained by transferring a solution of lecithins in methanol into an aqueous phase. A systematic study was performed by dynamic light scattering to determine the influence of several factors (lecithin concentration, ratio methanol/water, pH, salt content, stirring rate, etc…) on the size and polydispersity of the suspensions. Cryo-TEM pictures were taken and pointed out the formation of spherical small unilamellar vesicles. The incorporation of the preservative compound was then performed. The obtained suspensions were characterized by DLS and the influence of the ratio lecithin/preservative assessed. The encapsulation yield of the preservative was determined and optimized. Microbiological tests were carried out to evaluate the interest of nano-liposomes compared to non encapsulated forms of the same preservative compound. References: [1] Mozafari et al., Nanoliposomes and their applications in food nanotechnology, Journal of Liposome Research, 2008, 18, 309-327 [2] S.Stainmesse, H.Fessi, J.-P.Devissaguet, F.Puisieux, Process for the preparation of dispersible colloidal systems of amphiphilic lipids in the form of submicronic liposomes, EP0349429

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Fundamentals of nanotoxicity: Effect of nanoparticles on lowering the energetic barrier of membrane fusion Charlotte M. Beddoes ; Wuge H. Briscoe School of Chemistry, University of Bristol, Bristol, United Kingdom

How nanoparticles interact with cell membranes and affect the cellular processes is important to our fundamental knowledge of nanotoxicity. For nanoparticles to pass through the membrane, lipid molecules must undergo elastic deformations such as stretching, tilting and shearing as characterized by their elastic bending modulus, and thus an activation energy barrier must be overcome. It is our hypothesis that the nanoparticles themselves have the potential to lower this energetic barrier once exposed to the lipids. The molecular deformation experienced by the lipid molecules while the mesophase undergoes lamellar to non-lamellar transformation, are similar energetically to those involved in cell entry of nanoparticles. Therefore, we hope to shed light on the energetic of nanotoxicity by studying the effect of nanoparticles on mesophase transitions of model lipid systems. More specifically in this talk, we will report the results obtained from monoolein lipid mesophases invaded by SiO2 and TiO2 nanoparticles. We observed for the first time the alignment of mesophases induced by the presence of nanoparticles. Such alignment is a result of the interactions between the nanoparticles and the lipid molecules which lead to different curvatures that would have accompanied the mesophase organization. The extremely low nanoparticle concentration suggests that local defects created by the nanoparticles might initiate elastic deformation, leading to mesoscopic curvature transformation and alignment of mesophase domains. This implicitly points to the possible roles nanoparticles could play in lowering the energetic barrier that would hinder such transitions.

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Infrared study of structural changes of water encapsulated in AOT reverse micelles Tinatin Butkhuzi ; Manoni Kurtanidze ; Natia Mzareulishvili ; Marina Rukhadze I.Javakhishvili Tbilisi University, Chemistry, Tbilisi, Georgia

Reverse micelles have been the subject of a large number of experimental and theoretical investigations during the last two decades. They are powerful models for complex biological water cavities and wall pores in solid media. The surfactant sodium bis (2-ethylhexyl) sulfosuccinate (AOT) forms spherical nanometer-sized molecular aggregates in nonpolar solvents. The hydrocarbon part of the AOT molecules are oriented toward the exterior of the aggregate, while the sulfonate headgroups with the sodium counterion are localized in the interior of the reverse micelle. The goal of the preposed work was investigation of structural changes of water pools of reverse micelles depending from AOT concentration in the presence or absence of structure-making and structure-breaking ions by IR-Spectroscopy. Microemulsions were prepared on the basis of AOT, hexane, water, water solutions of sodium acetate and potassium perchlorate. IR absorption spectra were recorded in a IR spectrophotometer Specord M80. Results show, that the shape of water band in O-H streching region (3100-3700) varies with increasing of W within 1-10. It was found that intensity of O-H streching band is higher in the presence of acetate ions in comparison wich perchlorate ions at all AOT concentration values (0.01, 0.02, 0.03, 0.05, 0.1 M). Results may be useful in investigation of the interface features of AOT reverse micelle with unique properties as models for biomembranes and templates for nanoparticles.

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Towards understanding peptide self-assembly: a model system study Celen Cagri Cenker 1; Seyda Bucak 2; Ulf Olsson 1 1Lund University, Lund, Sweden; 2Yeditepe University, Istanbul, Turkey

The trifluoro acetate (tfa) salt of the synthetic peptides (ala)nlys, n= 4, 6, 8, 10, in water have been investigated in order to understand the effects of hydrophobic interactions on the peptide self-assembly. Unlike the peptide amphiphiles that have been studied over the years, these peptides have no surface active behavior. The peptides carry a net positive charge that ensures colloidal stability of the self-assembly structures through a long-range electrostatic repulsion. It has been found that a difference of 2 amino acids in the sequence leads to drastic changes in the self-assembly structures. A4K does not form any aggregates in the aqueous solutions of volume fraction, φ, φ = 0.41. A6K self-assembles into very long, hollow nanotubes with a radius R = 26 nm, above a critical aggregation concentration φcac=0.10. The monolayer-wall nanotubes, as indicated by SAXS data, reach close packing already at φ=0.15 and upon further increasing the concentration, a novel phase transition to lamellar phase where the peptide molecules form bilayers consisting of two, presumably oppositely oriented monolayers, occurs. For A8K and A10K, the self-assembly structure is fibrils with a finite size of circa 200 nm and a rectangular cross section of 4x8 nm as deduced from SAXS measurements.

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The development of lipid-based liquid crystal nanoparticles for protein/peptide drug delivery Doroty Codoni ; Maria O'Connell ; Sheng Qi University of East Anglia, School of Pharmacy, Norwich, United Kingdom

Lipid-based liquid crystalline phases allow controlled release of compounds of different physiochemical properties including: hydrophilic, lipophilic and amphiphilic molecules. Our previous study reported the novel use of Gelucire 50/13 to form liquid crystalline gels that have promising features such as mucoadhesion and protein entrapment. The focus of this study is to develop formulations that combine the advantages of nanoparticles and lipid liquid crystalline phase for enhanced protein/peptide delivery. Aqueous dispersions of nanoparticles were formed by fragmentation of the bulk gels. The dispersions of final concentration of 2% bulk gels and 98%water were homogenised with a high-pressure homogeniser. The particles were characterised using DLS, Cryo-TEM and AFM. Lysozyme was used as a model protein and the encapsulation efficiency was assessed by centrifugation and quantification with UV Spectroscopy. Release studies were carried out using dialysis membrane and the penetration of the nanoparticles through mucus was investigated using Franz diffusion cells. The diameter of the particles ranged between 150-200nm. The nanoparticles formed using a gel with 65% water showed highest polydispersity and smallest in size. The incorporation of Lysozyme increased the polydispersity of the particle size. No significant aggregation of the nanoparticles was observed in the samples stored at room temperature and at 4°C for up to 3 months. Cryo-TEM and AFM both confirmed that the nanoparticles are of disc shape and the measured particle sizes were consistent with those measured by DLS. The encapsulation efficiency of lysozyme inside the particles is above 65%. This study reported for the first time the ability of hydrated Gelucire 50/13 gels to form stable disk shape nanoparticles. These lipid-based nanoparticles demonstrated a high encapsulation efficiency for the model protein used in this study and have the potential to be used as carriers for protein/peptide drug delivery.

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Modeling of the topology of semi- rigid bicontinuos microemulsions : frustreated and un-frustrated structures Magali Duvail 1; Thomas Zemb 1; Lise Arleth 2; Stjepan Marcelja 3; Jean-Francois Dufreche 4 1CEA/DSM, ICSM, Bagnols sur Cèze, France; 2University of Copenhagen, Nanobioscience, Department of Basic Sciences and Environment, Copenhagen, Denmark; 3Australian National university, Department of Applied Mathematics, Canberra, Australia; 4University Montpellier 2 France, Institut de Chimie Séparative de Marcoule ICSM, Bagnols sur Cèze Cedex, France

Thermalized water-oil-surfactant dispersions of known volumes and spontaneous curvature can be generated via combination of wavelets. Since the curvature energy can be calculated, any microemulsion with known molecular interfacial area, volume and curvatures can be theoretically simulated and free energy of formation calculated. We investigated all possible ternary microstructures in the case of a ternary phase diagram in a large range of oil-water-surfactant concentrations. Globular and connected bicontinuous structures have been generated. The difference between fluid (bending constant < 1kT) and rigid microemulsions (bending constant > 1kT) have been analyzed. Also neutral packing with Gaussian and average bending constant compensating can be generated: these correspond to shape of polar heads, a second order term. The resulting phase diagrams exhibit the existence of microemulsions, competing with two phase domains and as well as a lamellar phase domain. Peak position scaled by the area per unit volume show universal behaviours. In this manner frustrated and un-frustrated microemulsion can exist. Frustration in bending energy can even lead to a miscibility gap when frustrated and un-frustrated bicontinuous microemulsions coexist.

81


Structure of gel-like surfactant solutions Felix Ertel 1; Günther Goerigk 2; Frank Polzer 3; Claudia Schmidt 1 1Universität Paderborn, Paderborn, Germany; 2Helmholtz-Zentrum Berlin, Berlin, Germany; 3Humboldt Universität zu Berlin, Berlin, Germany

As a model system for pharmaceutical and cosmetical creams, the ternary system consisting of sodium dodecyl sulfate/cetyl alcohol/water (SDS/CA/D2O) [1] can be used. In order to better understand the relationship between macroscopic physical properties and molecular structure and dynamics, we have investigated a series of samples containing a total amount of 3 wt. % SDS and CA at varying SDS/CA ratio. Mixtures with a high content of CA form stable gels and the viscosity of the samples decreases with increasing amount of SDS. Using 1H NMR spectroscopy and differential scanning calorimetry, we were able to detect that the gel-like character of the samples depends on the mobility of the alkylchains. The structure of the samples was determined by cryo-TEM microscopy and very small-angle neutron scattering (V-SANS) [2]. The cryo-TEM results obtained for a gel-like sample (97 wt. % D2O, 0.3 wt. % SDS, 2.7 wt. % CA) shows a mixture of unilamellar and multilamellar vesicles and larger plate-like structures. The V-SANS scattering curve shows a characteristic Q-2-behavior with some modulation indicating core-shell structures with a broad size distribution. With increasing amount of SDS the diameter of the vesicles decreases and rodlike aggregates occur. Reference: [1] R. J. Goetz, M. S. El-Aasser, Langmuir, 6, 132 (1990) [2] G. Goerigk, Z. Varga, J. Appl. Cryst., 44, 337 (2011)

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Quantum chemical analysis of incorporation of alkanes in the fatty alcohol monolayers at the water/vapor of alkanes interface Yuri Vysotsky 1; Olena Fomina 1; Elena Belayeva 1; Valentin Fainerman 2; Dieter Vollhardt 3; Reinhard Miller 3 1Donetsk National Technical University, department of physical and organic chemistry, Donetsk, Ukraine; 2Donetsk Medical University, Donetsk, Ukraine; 3Max Planck Institute of Colloids and Interfaces, department of interfaces, Potsdam/Golm, Germany

In the framework of semiempiric quantum chemical PM3 method the impact of alkane molecules CnH2n+2 (n=6-16) of vapor phase on the spontaneous clusterization process of aliphatic alcohols CnH2n+1OH (n=8-16) was considered at the water/alkane vapor interface. In the framework of exploit model water phase retracts alcohol functional group and from two to four adjoining to it methylene fragments (Δn). While alkane molecule orients straight on the interface because of its complete hydrophobicity. The hydrogen atoms of the methylene fragments of the surfactant and alkane hydrocarbon chains are all in the trans-position. Also we regard the case when alkane molecule are regularly spread amongst alcohol molecules and do not form individual domains in alcohol monolayer. It was shown that the spontaneous clusterization threshold of alcohols at the water/alkane vapor interface is 10-11 carbon atoms in the alcohol alkyl chain at 298 K as in the case of alcohols clusterization at the air/water interface that agrees well with present experimental data. It was revealed that inclusion of alkanes from the vapor phase into the different surfactants monolayers is possible for amphiphilic compounds possessing high values of their spontaneous clusterization threshold at the air/water interface nS

0(no less than 16 carbon atoms in the chain) and does not depend on the alkane molar fraction in the corresponding monolayer. Therewith the difference in the alkyl chain lengths of alcohols and alkanes capable of inclusion into the monolayer should be no more than nS

0-15 and nS0-14 for

alcohol 2D film 1 and 2D film 2 with Δn=3 and 2 respectively. Obtained results agree with present experimental data pointing out that monolayers of aliphatic alcohols and sodium dodecyl sulphate at the air/water and water/alkane vapor interfaces are more closely packed than that at the liquid interfaces where alkane molecules of the second liquid phase participate into the process of surfactant monolayer formation.

83


Distribution of organic additives in micellar solution of surfactants Jonas Fuchs ; Monika Schönhoff University of Muenster, Institute of Physical Chemistry, Muenster, Germany

Aqueous micellar solutions of either cationic, anionic or nonionic surfactants with dodecyl tails and aromatic additives are investigated by pulsed-field gradient NMR. Employing a fast exchange model, the micelle/water partition coefficient (f) is calculated from diffusion coefficients of both surfactant and additive. Additives with hydrophobicity, as specified by the octanol/water partition coefficients POW, in a medium range are chosen where a significant dependence of f on log(POW) has been found. The relevance of specific interactions of substituents of the aromatic additives with the surfactant’s head group versus the relevance of the additives overall hydrophobicity is explored. In addition interactions of the different head groups with the aromatic ring system are investigated. While typically the critical micelle concentration (cmc), the water solubility, the critical packing parameter and other properties depend on the shape and charge of the surfactant, here a novel coefficient is introduced, which describes the concentration dependence of the micelle/water partition coefficient. This coefficient allows comparisons of values of f for different surfactants with very different cmc, which can be analyzed only at very different concentrations.

84


Interaction between Dioctadecyldimethylammonium Bromide (DODAB) Vesicles and Pluronic F127 polymer network Luigi Gentile 1; Mohamed Youssry 2; Isabella Nicotera 1; Luigi Coppola 1 1University of Calabria, Rende (CS), Italy; 2Alexandria University, Alexandria, Egypt

In this study we investigate the surfactant-polymer interaction and the effect of the polymer gel network on the vesicular stability. The interactions between Pluronics and lipid vesicles are widely explored as they are considered the simplest model to mimic cell membranes. DODAB is a double-chained quaternary ammonium surfactant that forms unilamellar vesicles (ULVs) in water. It provides a good model for investigating the interaction between surfactant and Pluronic F127 polymer. The F127 is a nonionic triblock copolymer in which a hydrophobic poly(propylene oxide) central block is linked to hydrophilic poly(ethylene oxide) end blocks. By means of rheology and differential scanning calorimetry (DSC) we report the ULVs presence in the polymer network. The DSC data follow the critical micellization temperature of F127, the gel-liquid crystal transition of the DODAB bilayer and of F127/DODAB mixtures. Using rheology, the effect of the gel network on the DODAB vesicular stability has been studied.

85


Physicochemical investigation on the bulk and surface properties of the binary mixtures of sodium N-dodecanoyl sarcosinate, SDDS and N-decanoyl -N-methylglucamine, MEGA 10 in aqueous medium Soumen Ghosh Jadavpur University, Chemistry, Kolkata, India

Self-aggregation of non-ionic N-methyl-N-decanoyl glucamide (Mega 10) and anionic N-methyl-N-dodecanoyl sodium glycinate (SDDS) have been investigated by different physical methods such as tensiometry, conductometry, microcalorimetry, spectrophotometry, fluorimetry and circular dichroism throwing light on both bulk and interfacial behaviors of the micellar systems. The counter-ion binding, surface excess quantity, head group area have been evaluated. The thermodynamic parameters of the micellization process have been calculated, reported and discussed. The aggregation numbers and micropolarity have also been determined. Both surfactants individually as well as in mixed condition show circular dichroism spectra which are quite uncommon in literature with respect to mixed micelle. The different experimental results have been analyzed in the light of the theories of Rubingh, Maeda and Rosen, and the overall shapes of the mixed micelles have been predicted from the estimation of the amphiphile packing parameter.

86


Polyoxometalate surfactants as unique molecules for interfacial self assembly Juan J. Giner-Casares 1; Gerald Brezesinski 1; Helmuth Moehwald 1; Steve Landsmann 2; Sebastian Polarz 2 1MPI for Colloids and Interfaces, Potsdam, Germany; 2University of Konstanz, Konstanz, Germany

The hierarchical organization of materials on multiple length scales represents one of the key steps towards the emergence of advanced properties. The formation of supramolecular aggregates by self assembly processes is one of the most valuable tools for structuring. As the design of supramolecular structures is expanded, more complex architectures are reached. In order to improve the reproducibility and simplicity in experimental procedures, a decrease of the number of the required building blocks is highly desirable. Surfactants occupy a leading position in interfacial self assembly, with a fundamental relevance in many areas from biology to nanotechnology. Polyoxometalates (POMs) are molecular metal oxo clusters. POMs and their supramolecular assemblies are materials of high relevance due to their performance in catalysis, non linear optics, energy storage, magnetism, and medicine. A completely new series of surfactants has been developed. The POM unit is covalently bound to two saturated hydrocarbon chains at exclusively one side of the POM unit. The new POM surfactants resemble the molecular structure a classical surfactant, with a net dipolar moment. Whereas commonly Langmuir monolayers are structurally dominated by the aliphatic chains, we present here monolayers where the chains merely serve anchoring at the air/water interface and the organization is dictated by the hydrophilic head groups self assembling in a hexagonal lattice. The first experimental evidence of ordered polar headgroups giving rise to a diffraction pattern is observed. The chain length has been systematically varied, allowing for a general study of the impact of the chain length on the supramolecular structure. These model structures are studied here by a combination of modern techniques, the leading ones being X ray reflectivity and Grazing Incidence X Ray Diffraction.

87


pH- and salt-dependent aggregation behavior of symmetric single-chain bolaphospholipids Gesche Graf 1; Simon Drescher 2; Annette Meister 3; Bodo Dobner 2; Alfred Blume 1 1Martin-Luther-University Halle-Wittenberg, Physical Chemistry, Halle, Germany; 2Martin-Luther-University Halle-Wittenberg, Pharmacy, Halle, Germany; 3Martin-Luther-University Halle-Wittenberg, ZIK HALOmem, Halle, Germany

Long-chain bolaphospholipids with a single alkyl chain and two phosphodimethylethanolamine headgroups (Me2PE-C32-Me2PE) self-assemble in water into fibers and spherical micelles depending on the temperature, the pH value and the salt concentration of the suspension. They gel water very efficiently by the formation of a three-dimensional network of nanofibers that are built up by stretched bolaphospholipid molecules with an all-trans conformation of the alkyl chain.1-3 The Me2PE headgroup is zwitterionic at pH 5 and can be deprotonated at higher pH values. This results in negatively charged headgroups leading to repulsive interaction between the molecules. pH-dependent DSC measurements were carried out that suggest a significant destabilization of the fiber aggregates and no gelation at ambient temperature above pH 10. TEM images supported this assumption. Further DSC and rheological measurements were performed at pH 11 with different salt concentrations (NaCl, KCl, MgCl2 or CaCl2) to examine the influence of mono- and divalent cations on the bolalipid system. It was shown that the cations were able to shield the electrostatic repulsion of the headgroups enabling the formation of nanofibers and a viscoelastic gel at ambient temperature.4 (1) K. Koehler, A. Meister, G. Foerster, B. Dobner, S. Drescher, F. Ziethe, W. Richter, F. Steiniger, M. Drechsler, G. Hause, A. Blume, Soft Matter 2006, 2, 77. (2) A. Meister, M. Bastrop, S. Koschoreck, V. M. Garamus, T. Sinemus, G. Hempel, S. Drescher, B. Dobner, W. Richtering, K. Huber, A. Blume, Langmuir 2007, 23, 7715. (3) A. Meister, S. Drescher, V. M. Garamus, G. Karlsson, G. Graf, B. Dobner, A. Blume, Langmuir 2008, 24, 6238. (4) G. Graf, S. Drescher, A. Meister, B. Dobner, A. Blume, J. Phys. Chem. B 2011, 115, 10478.

88


Characterization of carbon nanotube dispersions in solutions of bile salts and their derivatives Marta Gubitosi 1; Luciano Galantini 1; Nicolae V. Pavel 1; Delia Gazzoli 1; Simona Sennato 2; Oren Regev 3 1Sapienza Università di Roma, Dipartimento di Chimica, Roma, Italy; 2Sapienza Università di Roma, Dipartimento di Fisica e CNISM, Roma, Italy; 3Ben Gurion University of the Negev, Chemical Engineering Department, Beer-Sheva, Israel

Carbon nanotubes (CNTs) have been recognized as a material of great interest for their mechanical, electrical, thermal and optical remarkable properties. Most applications require the nanotubes to be dispersed, preferably as individuals, but their implementation has been hampered since they are insoluble in a lot of organic solvents and in water. Therefore, dispersions of single CNTs can be usually achieved by solubilising them in water with the aid of biocompatible surfactants, such as bile salts (BS).[1] In this work the ability in dispersing CNTs of some bile salts (BS), derivatives of bile salts (DBS), characterized by the presence of aromatic substituents,[2] and some conventional surfactants (SDS, CTAB) has been compared. For each surfactant Raman, UV-vis-NIR spectroscopy, and AFM images were used to characterize these dispersions, in terms of surfactant efficiency and suspensions quality (CNTs dispersion state). It has been observed that BS and DBS are usually more effective than other surfactant, such as SDS, concerning both quality and dispersing ability. It is likely due to their facial amphiphilic structure, related to the presence of two faces with different polarities on a rigid condensed tetracyclic system, that determines a particularly high CNT surface covering level. This property is crucial in the determination of the particularly effective dispersion ability of the studied derivatives. The introduction of aromatic residues on BS, as in the studied DBS, do not improve their dispersing ability, despite the well-known affinity of aromatic system with the CNT surface. AFM images are obtained in order to have a more complete characterization of the CNT suspensions, and to confirm the good state of the dispersions. [1] M.J. O’Connel et al., Science, 2002, 297, 593 [2] M.F. Islam: E.Rojas; D.M. Bergery; A.T. Johnson; A.G.Yodh, Nano Lett., 2003, 3, 269

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Tailored self-assembly structures of magnetic nanoparticles by tuning interparticle interactions Manuela Hod 1; Celin Dobbrow 2; Annette Schmidt 2; Moshe Gottlieb 1 1Ben Gurion University of the Negev, Chemical Engineering, Beer Sheva, Israel; 2Universität zu Köln, Department Chemie, Köln, Germany

The controlled self-assembly of ferromagnetic nanoparticles is of significant practical relevance for various prospective technological applications. In this work we present a novel strategy for the modification of the interaction potential between ferromagnetic cobalt nanoparticles by varying the amount of a co-surfactant during the synthesis. The cobalt nanoparticles are synthesized by thermolysis in the presence of polystyrene and tri-n-octylphosphine oxide (TOPO) as co-surfactant. Polystyrene, on the one hand is applied as steric stabilizer of the magnetic fluid while TOPO on the other hand, creates a positive surface charge on the particle surface. Therefore, the particle interaction potential consists of magnetic dipole-dipole attraction and repulsive contributions from electrostatic and steric stabilization. We examine the effects of the amount of TOPO on the particles and the concentration of particles in the system on the resulting self-assembled structures. In both cases we found a strong impact of TOPO on the structure formation. Transmission electron microscopy (TEM) and cryo-TEM were used to investigate the TOPO-dependent structuring as the structure varies from chain-like structures at zero TOPO concentration towards full separation of single particles at the highest amount of co-surfactant. Moreover, the induced charge on the surface is estimated by zeta-potential measurements. By this method we obtained the charge-per-mass ratio that showed an unexpected dependence on particle concentrations. In addition, scattering techniques are applied for the characterization in dispersion. With dynamic light scattering we measured the diffusion coefficients of the particles, applying the Stokes-Einstein relation for samples with high TOPO concentration and the Maeda-Fujime model for chainlike structures. Both, electron microscopy and scattering techniques show direct correlation between the amount of TOPO and the self-assembly structure of the particles.

90


Formulation of bicontinuous and water- in - diesel microemulsions using nonionic surfactants and hydrophilic alcohol ethoxylates as co- surfactant Ibrahim Kayali 1; Ulf Olsson 2 1Al-Quds university, Chemistry and Chemical technology, Jerusalem, Palestinian Territory; 2Lund University, Physical Chemistry 1, Lund, Sweden

Bicontinuous and water in diesel microemulsions were formulated using single nonionic alkyl poly glycol ethers combined with hydrophilic alcohol ethoxylates. The phase behavior at temperatures ranging from 0 C to 50 C was investigated. Visual inspection as well as cross polarizers were used to detect anisotropy. The fish phase diagrams were determined. The presence of the hydrophilic alcohol ethoxylates was necessary to initiate both types of microemulsions. Increasing the hydrophobic chain length of the surfactant led to a wider range of temperature stability at lower surfactant concentration. Meanwhile increasing the ethylene oxide units in the head group by two units led to a phase diagram that is dominated by lyotropic liquid crystal. The relatively low amount of surfactant needed to formulate the water in diesel microemulsion in this work provides a feasible option for alternative fuel. The advantages of the water in diesel microemulsion fuel are reducing health hazardous by minimizing the emissions of nitrogen oxide compounds and soot in addition to reducing fuel consumptions by improving the combustion efficiency

91


Physicochemical investigation of mixed reverse micellar systems in biocompatible oils: II. Microstructure by conductance and DLS Kaushik Kundu Indian Statistical Institute, Geological Studies Unit, Physics and Earth Science Division, Kolkata, India

Temperature-induced percolation behavior in mixed reverse micellar systems comprising anionic surfactant, sodium bis(2-ethylhexyl) sulfosuccinate (AOT), and nonionic surfactant, polyoxyethylene(20) sorbitan trioleate (Tween-85) in biocompatible oils e.g., ethyl oleate (EO), isopropyl myristate (IPM) and isopropyl palmitate (IPP) have been studied at a total surfactant concentration (ST) of 0.25 mol dm-3. The threshold percolation temperature (Tp) of these systems has been found to be dependent on water content (ω), content of nonionic (XTween-85), total surfactant concentration (ST), oil and concentration of added electrolyte (NaCl). The scaling laws for the temperature-induced percolation have been found to be obeyed but the equation parameters in pre and post-percolation regions differ in magnitude from what theory predicts. The standard free energy change (ΔG0cl), enthalpy change (ΔH0cl) and entropy change (ΔS0cl) of cluster formation have been evaluated at different physicochemical environments. Tp has been determined for systems as referred above, in presence of acetyl modified amino acids (MAA) as additives viz., N-acetyl-l-glycine (NAG), N-acetyl-l-leucine (NAL), N-acetyl-l-glutamic acid (NAGA) and N-acetyl-l-cysteine (NAC). The activation energy, Ep has been estimated for the percolation process of these systems both in absence and presence of additives. A mathematical model has been proposed for the estimation of various structural parameters, i.e., aggregation number (Ns), radius of droplet (Re), radius of water pool (Rw), surface number density of surfactant molecules (αs), the effective droplet number per unit volume of solution (Nd) and the interfacial area per surfactant molecules of the mixed reverse micellar systems, water/AOT/Tween-85/IPM. Droplet dimensions have also been measured by dynamic light scattering studies (DLS). An attempt has been made to underline the microstructures of these systems in the light of percolation of conductance vis-á-vis thermodynamics of droplet clustering and structural parameters.

92


Synthesis of an amineoxide zwitterionic surfactant and characterization of its dual function of detergency and softness JongChoo Lim 1; DongSung Han 2 1Dongguk University, Chemical and Biochemical Engineering, Seoul, Republic of Korea; 2Aekyung Industrial Co, Central Research Laboratories, DaeJeon, Republic of Korea

In this study, an amine oxide surfactant of high molecular weight having a dialkyl amide chain was synthesized mainly for detergent formulation purpose where solubility of a newly synthesized surfactant was controlled by adduct with 5 moles of ethylene oxide and 2 moles of propylene oxide. The characterization of a surfactant was performed by 1H-NMR and 13C-NMR and the composition was compared with the expected composition calculated from the equilibrium distribution of feeding materials. Since this newly synthesized amine oxide surfactant is the bulky amphoteric surfactant, it can serve as a dual function surfactant by a single molecule through the interconversion of cleaning and softening effects depend on pH variations of the aqueous solution. The newly synthesized surfactant shows not only detergency but also mildness effect since it shows characteristics of a nonionic surfactant in an alkaline condition, while showing characteristics of a cationic surfactant in a neutral pH condition. The dual function characteristics depending on pH of the aqueous solution were investigated using QCM (quartz crystal microbalance) and zeta potential measurement with related cleaning and mildness effects. In addition, the physical properties of an amine oxide surfactant such as critical micelle concentration, surface tension, interfacial tension, contact angle and viscosity were measured.

93


Printed gold nanoparticle-based electrodes on paper Anni Maattanen 1; Petri Ihalainen 1; Himadri Majumdar 2; Petri Pulkkinen 3; Bjorn Torngren 1; Tom Lundin 1; Ronald Osterbacka 2; Heikki Tenhu 3; Jouko Peltonen1 1Abo Akademi University, Laboratory of Physical Chemistry, Center of Excellence for Functional Materials, Turku, Finland; 2Abo Akademi University, Department of Physics, Center of Excellence for Functional Materials, Turku, Finland; 3University of Helsinki, Laboratory of Polymer Chemistry, Center of Excellence for Functional Materials, Helsinki, Finland

Spherical gold nanoparticles (AuNP) were synthesized according to a procedure from Hostetler et al. [1] The particles were coated with a thiol layer which prevents them from aggregating and makes them easily dispersed in organic solvents and thus appropriate inks for inkjet-printing. Fully recyclable multicoated paper with a barrier against liquid penetration was used as the print substrate. The small size (d<5 nm) and a relatively low melting point of the nanoparticles enabled the low temperature infrared (IR) sintering of printed gold patterns. [2] Upon sintering, the amorphous layer of printed AuNPs (dark red) turned to a crystalline layer appearing gold-colored and possessing high conductivity. The print quality of the gold electrodes was optimized and the gold electrodes were further functionalized by self-assembled thiol monolayers. The gold electrodes were characterized by surface sensitive techniques. References: [1] M.J. Hostetler et al. Langmuir, 14 (1998) 17 – 30. [2] A. Määttänen et al. ACS Appl. Mater. Interfaces, 4 (2012) 955 – 964.

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Requirement of charged lipids for the hexadecanol-induced gelation in the phospholipid bilayer system Yasuharu Nakagawa 1; Masahiro Ota 2; Hiromitsu Nakazawa 2; Satoru Kato 2 1Kracie Home Products, Ltd., Beauty Care Laboratory, Yokohama-city, Kanagawa, Japan; 2Kwansei Gakuin University, Department of Physics, School of Science & Technology, Sanda-city, Hyogo, Japan

We have reported that the crude hydrogenated soybean lecithin (PC70) formed a homogeneous gel with hexadecanol (HD) in water, whereas the purified lecithin did not. PC70 contains a variety of phospholipids including phosphatidylethanolamine, phosphatidylinositol, phosphatidylglycerol and so forth in addition to ~70% phosphatidylcholine and is in common use in cosmetic industries as a commercial raw material. On the basis of the speculation that the charged lipids including in PC70 may play a crucial role in the formation of the homogeneous gel, we investigated the effect of HD on the simplified lipid system composed of distearoylphosphatidylcholine (DSPC) and an acidic lipid, distearoylphosphatidylglycerol (DSPG), by rheometry, freeze-fracture electron microscopy, differential scanning calorimetry (DSC) and synchrotron X-ray diffraction. We found that only a small amount of DSPG was required to induce a homogeneous gel in the DSPC/HD/water system. In addition, DSC measurements revealed that the chain-melting transition in the phospholipids/HD/water system sharpened and shifted toward higher temperatures as the molar fraction of HD, MH, was increased up to ≈ 0.66. When MH > 0.66, it stayed constant and two more endothermic peaks appeared at lower temperatures probably due to the segregation of HD crystals. These results suggested that the complex was formed at MH ≈ 0.66. As the molar ratio of DSPG was increased keeping MH = 0.66, the appearance of the lipid dispersion changed from a phase separation to a homogeneous gel solution. Structural analyses showed the change in the bilayer morphology and lamellarity from multi- to single lamellar states on addition of DSPG. The fact that the addition of DSPG gives rise to the morphological change of the bilayer and the homogeneous distribution of the bilayer throughout the solution suggested that distribution of charged lipids in bilayer membranes is required to promote the homogeneous hydrogel formation.

95


Change in secondary structure of model peptide in pulmonary surfactant systems at the air-water interface Hiromichi Nakahara ; Sannamu Lee ; Osamu Shibata Nagasaki International University, Department of Biophysical Chemistry, Faculty of Pharmaceutical Sciences, Sasebo, Nagasaki, Japan

The surface properties and behavior of pulmonary surfactant preparations containing an amphiphilic peptide (Hel 13-5), which is a mimicking peptide of natural SP-B protein and is charged positively, have systematically been investigated employing the monolayer technique. In addition, a secondary structure of Hel 13-5 in the aqueous solutions with phospholipids is mainly α-helical structure. In the previous study, Hel 13-5 in the mixtures with phospholipid monolayers changes its conformation from the α-helix to the extended β-sheet as surface pressure increases upon compression, and this interconversion is found to be irreversible even during expansion process of monolayers. Furthermore, the electrostatic interaction between the positively charged phospholipid and Hel 13-5 inhibits to some extent the interconversion to the β-sheet during compression. In the present study, the in situ polarization modulation-infrared reflection absorption spectroscopy (PM-IRRAS) was used to evaluate secondary structure of Hel 13-5 in the monolayer state at the air-water interface. The conformation of single Hel 13-5 monolayers adopts α-helix up to its monolayer collapse. Beyond the collapse pressure, the secondary structure sifted to a β-sheet. In addition, as for the DPPC/PG/PA(=68/22/9, by weight)/Hel 13-5 preparations, the magnitude of α-helix mode was changed with surface pressures. The spectrum frequency in the amide region (1500-1700 cm-1) obtained from PM-IRRAS has been confirmed by comparing with that from ATR-FTIR for the corresponding bulk films. Furthermore, a tilt angle of Hel 13-5 molecules at high surface pressures was calculated combining PM-IRRAS with ATR-FTIR spectra.

96


Langmuir monolayer properties of a series of partially fluorinated alcohols Hiromichi Nakahara 1; Seiichi Sakamoto 1; Ichiro Fujita 1; Shohei Nakamura 2; Masafumi Nakaya 3; Kiyoshi Kanie 3; Atsushi Muramatsu 3; Osamu Shibata 1 1Nagasaki International University, Department of Biophysical Chemistry, Faculty of Pharmaceutical Sciences, Sasebo, Nagasaki, Japan; 2Matsuyama University, Department of Pharmaceutical Technology, College of Pharmaceutical Sciences, Matsuyama, Ehime, Japan; 3Tohoku University, Institute of Multidiscipnary Research for Advanced Materials, Sendai, Miyagi, Japan

Partially fluorinated long-chain alcohols (FnHmOH; n = 4, 6, 8, m = 7, 9, 11) were newly synthesized. The obtained crudes were purified by thrice recrystallizations from the H2O/CH3COCH3 mixed solvent. And then the purified FnHmOH was checked by elementary analysis, proton and carbon nuclear magnetic resonance (1H-NMR, 13C-NMR), and time of flight mass spectrometry (TOF-MS). In addition, the melting point of FnHmOH was measured with differential scanning calorimetry (DSC). Furthermore, the surface pressure (π)-molecular area (A) and surface potential (ΔV)-A isotherms for FnHmOH monolayers were measured at 283.2−303.2 K on water subphase. The melting point increases with increasing chain length. However, the melting point decreases with a increase in fluorination degree in the FnHmOH structures. In comparison to the corresponding hydrogenated fatty alcohols, the melting point of F4H11OH and F6HmOH is smaller than that of the corresponding alcohols. In Langmuir monolayer study, all extrapolated areas of FnHmOH monolayers from the π-A isotherms converge in the range from 0.3 to 0.4 nm2. In addition, their minimum surface potential at the close-packed state is concentrated at - 700mV. In addition, the slope of an disordered/ordered phase transition pressure against temperature was used to evaluate the apparent molar quantity change. The temperature dependence of the isotherms for the fluorinated alcohols, as opposed to the corresponding hydrogenated alcohols, is quite smaller. These results will be useful information for the thermal stability of fluorinated amphiphiles.

97


Fabrication of silver nanosheet by reduction on gas-liquid interface Takayuki Narita 1; Yoshinobu Kai 1; Tetsuya Kida 2; Yushi Oishi 3 1Saga University, Saga, Japan; 2Kyushu, Department of Energy and Material Sciences, Kyushu, Japan; 3Saga University, Chemistry and Applied Chemistry, Saga, Japan

Amphiphilic monolayers on water have a flat surface on an atomic-scale. Hence, one may be useful for fabricating a flat metal sheet from metal ion aqueous solutions by using the monolayer consisting of reductive amphiphiles on the solution as a template. In this study, the formation behavior of a silver nanosheet prepared on aniline monolayer with a photo-reductive property was investigated as functions of the concentration of aqueous silver nitrate solution and irradiation time of UV-VIS light by a field emission-scanning electron microscopy (FE-SEM) and an atomic force microscopy (AFM). 115 ml chloroform solution of 4-hexadecyl aniline with a concentration of 2.0 mM was spread on a subphase in a glass petri-dish at 293 K. The subphases were the silver nitrate solution with concentrations of 5.0, 25 and 50 mM. The fluorescent light was irradiated to these glass petri-dishes for 3 or 7 h. The irradiated monolayers were transferred onto mica and silicon wafer by the surface-lowering method for AFM in air and FE-SEM observations, respectively. By UV-VIS irradiation for 24 h, some floating particles macroscopically visible on the subphase covered with the aniline monolayer, whereas no such particles were observed in aqueous silver nitrate solution without the aniline monolayer. This indicates that the aniline monolayer on an aqueous silver nitrate solution accelerates the reduction of silver nitrate ion by the irradiation at an air-water interface. The Plates 250 – 300 nm in thickness was observed in the AFM image of aniline monolayer exposed to fluorescent light for 7 h on 50 mM silver nitrate solution. It is independent of the concentration of an aqueous silver nitrate solution. Its area, however, increased with the concentration of an aqueous silver nitrate solution. The contrast images due to a difference in electron density in FE-SEM observations for the similar shaped and size plates to that by AFM also supports the formation of silver nanosheet on the aniline monolayer. It is suggested that an increase in irradiation time promotes the reduction of silver, which results in the growth and subsequent aggregation of silver nuclei to form flat plates.

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Combining molecular dynamics simulations (MD) and solid state nuclear magnetic resonance (NMR) methods for amphiphilic systems Samuli Ollila ; Tiago Ferreira ; Daniel Topgaard Lund University, Lund, Sweden

A lot of structural and dynamical information can be extracted from the solid state NMR measurements for amphiphilic systems, however the interpretation of the results might be sometimes tedious. On the other hand, the structural and dynamical information can be extracted also from atomistic MD simulations. Combining these two techniques we are able to test very rigorously the quality of simulation models, and also use the simulations to interpret NMR measurements. We have used this approach for simple surfactants (non-ionic surfactants, and cetyltrimethylammoniumchloride), and also for cell membrane model systems (POPC/cholesterol mixture). We focus on 13C-1H residual dipolar couplings and 13C relaxation rates, which are determined by the rate and anisotropy of C-H bond vector reorientation, as well as 1H-1H cross-relaxation rates, which depend on the internuclear distance. With this combination of techniques we are able to extract very detailed and experimentally verified information on structure and dynamics of surfactant systems.

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Tuning microstructure of non-ionic micellar networks: rheology and self-diffusion investigations Ruggero Angelico 1; Andrea Ceglie 1; Sergio Murgia 2; Ulf Olsson 3; Gerardo Palazzo 4; Samiul Amin 5 1Università del Molise, Dipartimento Agricoltura, Ambiente e Alimenti, Campobasso, Italy; 2Università di Cagliari, Dipartimento di Chimica, Cagliari, Italy; 3Lund University, Physical Chemistry 1, Lund, Sweden; 4University of Bari, Dept. of Chemistry, Bari, Italy; 5Malvern Instruments, Malvern, United Kingdom

Through a combination of rheology and NMR-PGSE techniques we were able to monitor the structural transition from branched to disconnected micellar network formed by the PhosphatidylCholine (PC), a well known phospholipid commonly extracted by natural sources (soybean). PC can be dissolved in a large variety of organic solvents, giving rise in many cases to the formation of reverse water-in-oil wormlike micelles in presence of trace amounts of water. Previous investigations showed that PC reverse micelles can undergo either to a sphere-to-rod-to-sphere transition if the dispersing organic phase is cyclohexane (cC6) or to the formation of a multiconnected network of cylindrical micelles if the oil is isooctane (iC8). From the point of you of phase equilibria, in cC6 a Winsor II-type phase separation is observed above a threshold value of the water/PC molar ratio (W0) whereas a phase separation between a dense gel and almost pure oil (gas-liquid) is found above a critical W0 value in iC8. Although the scenario is expected to be far more complex when these two types of hydrocarbons that individually form different topological defects are mixed, the use as a solvent of cC6/iC8 solutions could allow a fine tuning of the branch density. In the present work we intend to investigate the influence of the composition of cC6/iC8 mixture, described through the isooctane weight fraction R= wt(cC6)/[wt(cC6)+wt(iC8)], on the microstructure and how this can be coupled to the other control parameter defined by W0. The results are discussed in terms of relative capacity of both the mixed solvents (R-control parameter) and water (W0-control parameter) to swell the paraffinic PC chains and head group size, respectively, those parameters making energetically favourable end-caps, branch junction points, or a combination of both. References: [1] Olsson, U.; Börjesson, J.; Angelico, R.; Ceglie, A.; Palazzo, G. Soft Matter 2010, 6, 1769–1777 [2] Angelico, R.; Oliviero Rossi, C.; Ambrosone, L.; Palazzo, G.; Mortensen, K.; Olsson, U. PCCP, 2010, 12, 8856-8862. [3] Ambrosone, L.; Angelico, R.; Ceglie, A.; Olsson, U.; Palazzo, G. Langmuir 2001, 17, 6822-6830.

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Characterisation of polymer-bile salts aggregation and its impact on poorly water soluble drugs solubilisation in the gut Claudia Pigliacelli 1; Andrew Kirby 2; Patrick Gunning 2; Francesca Baldelli Bombelli 1; Pete Wilde 2; Sheng Qi 1 1University of East Anglia, School of Pharmacy, Norwich, United Kingdom; 2Institute of Food Research, Norwich, United Kingdom

Bile salts, anionic surfactants present in the gut, can interact with hydrophilic polymers used in pharmaceutical formulations, leading to the formation of polymer-bile salts complexes. In this study polymer-bile salts aggregation and its impact on poorly-water soluble drugs solubilisation in the gut were investigated. Formulations were prepared by spray drying PVP and a model drug, griseofulvin. Sodium taurocholate (NaTC) was used as the model bile salt. Nanosight, DLS, Cryo-TEM and AFM were used to characterise the PVP–NaTC aggregation, in conditions simulating intestinal fasted (FASSIF) and fed states (FESSIF). Dissolution studies were performed with and without the presence of NaTC to study the effect of PVP-NaTC nano-complexes on the drug release. The impact of lecithin on the polymer-NaTC aggregation and drug solubilisation was also investigated. Nanosight results of the spray dried PVP alone formulation indicated that PVP-NaTC complexes with size of 100 nm formed in FASSIF, while in the FESSIF two populations of aggregates with sizes of 80 and 180 nm were present. In the presence of drug, PVP-NaTC complexes swell up to 300 nm in both fed and fasted states, suggesting the occurrence of drug encapsulation in the complexes. DLS results showed the dependence of aggregates size and poly-dispersity on the polymer/drug ratio, with the formation of bigger and more poly-disperse aggregates at higher PVP concentrations. The presence of lecithin resulted in the formation of liposomes with a mean size of 120 nm in FASSIF, while in FESSIF, the higher NaTC concentration led to liposome dissociation and subsequent formation of 320 nm mixed micelles. Dissolution studies showed a significant increase in drug solubilisation and release rate. These results confirmed the formation of PVP-NaTC complexes in simulation intestinal fluids. The resulting nano-complexes showed the ability to solubilise/encapsulate poorly-water soluble drugs which may impact on drug absorption in the gastrointestinal tract.

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EO-grafted polyanions with a cationic surfactant to prepare water-soluble complex salts or stabilized inorganic nanoparticles Ana Maria Percebom 1; John Janiak 2; Karin Schillén 2; Lennart Piculell 2; Watson Loh 1 1University of Campinas, Institute of Chemistry, Campinas - SP, Brazil; 2Lund University, Division of Physical Chemistry 1, Lund, Sweden

Polyelectrolytes are known to drastically affect the phase behavior of oppositely charged surfactants. Generally, at stoichiometric charge ratio, an associative demixing occurs and the formed complex salt is concentrated in a phase coexisting with a dilute phase. The architecture of polyion is an important factor in the characteristics of the assemblies and the present study investigates the phase behavior of complex salts using methacrylate polyions carrying ethylene oxide (EO) side chains of different lengths and at varying grafting densities. Complex salts with stoichiometric charge ratio and free of simple counterions were prepared using the mentioned copolyanions neutralized by the cationic surfactant hexadecyltrimethylammonium (C16TA). This strategy allowed the production of water-soluble complex salts, depending on the length and amount of EO side chains. SAXS, DLS and diffusion NMR were important to characterize the aggregates stabilized in water by the hydrophilic side chains, to analyze properties of the system (stability, thermosensitivity), and to identify the different mesophases observed due to the rich phase behavior presented. Polyelectrolytes can also be used to coat inorganic nanoparticles by electrostatic complexation. One example is the recovery of gold nanorods preformed and involved by a C16TABr bilayer to avoid the surfactant dissociation and the nanorods precipitation. The use of the previously mentioned grafted polyanions is an alternative way to coat/stabilize the nanoparticles, giving rise to PEO-stabilized nanoparticles that is currently under investigation in our group. Hence, it is another example of the importance of the complexation of polyions and oppositely charged surfactants to colloidal systems and its potential applications.

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Mixed micellization between kappa- and beta-caseins Irina Portnaya ; Sharon Avni ; Uri Cogan ; Dganit Danino Technion – Israel Institute of Technology, Biotechnology and Food Engineering, Haifa, Israel

The molecular association of individual caseins to form the milk casein micelles is still an unresolved issue. Kappa- and beta-caseins are key players in maintaining the stability of these complex aggregates. Recently we studied the micellization and thermodynamic behavior of beta-casein at different temperatures, pH, and ionic strength [1,2]. The present work deals with the interaction between kappa- and beta-caseins. Beta-casein, contains a large, hydrophobic C-terminal domain and a polar, negatively charged N-terminal domain at neutral pH. Kappa-casein, as opposed to beta-casein, has a predominantly hydrophilic C-terminal block and a hydrophobic N-terminal end. Consequently, both proteins possess the ability to self-organize into detergent-like micelles. Kappa-casein further assembles into amyloid-like fibrils, which are associated with numerous degenerative diseases. Although kappa-casein is not considered a disease-related protein, fibrillization of this protein, and inhibition of this process by beta-casein [3] may assist in studying the fibril formation phenomena in these diseases. The self-association of kappa-casein and its mixed micellization with beta-casein were studied by isothermal titration calorimetry (ITC) and cryogenic-transmission electron microscopy (cryo-TEM). We found that the self-organization of kappa-casein at low concentrations is highly sensitive to the temperature and incubation time. This we correlate with several parallel pathways of the protein self-association into oligomeric aggregates, micelles, and beta-sheet amyloid-like fibrils [4]. ITC was used to determine binding parameters between kappa- and beta-caseins in the mixed protein solutions. The combination of calorimetry and cryo-TEM clearly shows the formation of mixed micelles, and clearly demonstrate that beta-casein can decrease or even prevent kappa-casein fibrillization. 1.Portnaya, I., et al. J Agric Food Chem, 2008. 56(6): p. 2192-8. 2.Portnaya, I., et al. J Agric Food Chem, 2006. 54(15): p. 5555-61. 3.Thorn, D.C., et al. Biochemistry, 2005. 44(51): p. 17027-17036. 4.Farrell, H.M., et al. Journal of Protein Chemistry, 2003. 22(3): p. 259-273.

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Physicochemical and functional properties of surfactants and their mixtures used in wetting agents in fire fighting Krystyna Prochaska 1; Joanna Rakowska 2; B Twardochleb 3 1Poznan University of Technology, Poznan, Poland; 2Research Centre for Fire Protection, Józefów, Poland; 3Institute of Heavy Organic Synthesis "Blachownia", Kêdzierzyn-Kozle, Poland

Wetting agents are applied both directly to fire suppression, to finish extinguishing of fire and to preparing barrage belts, preventing against the proliferation of the fire. With the most significant characteristic of the wetting agent is showing its ability to moistening and to adsorbing. Wetting, i.e. the flowing of liquid on the solid surface is depending on interaction of molecules on the interfaces: solid, liquid and gas. Liquid is wetting the solid, when relation between molecules of solid and liquid is bigger than the surface tension of liquid. Rheological character of liquid has significant influence on the course of the curve of wetting of solid surface. Therefore, the value of surface tension only fulfils subsidiary role rather than settling in the evaluation of the effectiveness of the wetting agent. Obtaining the prescription of the extinguishing agent for fire protection demands a selection of suitable components. In this type of composition they are applied anionic surfactants and their mixtures with nonionic derivates. Using mixtures is particularly important from the point of view of synergism in lowering the surface tension, as well as improve foaming properties. Physicochemical properties: surface tension, adsorption dynamic, wetting of surface with the different hydrophobicity and functional properties: wettability, adsorptivity and foamability of surface-active agents and their binary mixtures, of potential elements of the composition firefighting was compared in this work in the purpose of getting effective wetting agent. The work was financially support by 32-067/12 DS-PB

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Albumin binding onto synthetic vesicles Carlotta Pucci ; Anita Scipioni ; Camillo La Mesa "La Sapienza" University, Chemistry, Rome, Italy

Vesicular mixtures containing didodecyldimethylammonium bromide and sodium dodecylsulfate in non-stoichiometric ratios were prepared and characterized. They bear a positive surface charge density, due to the cationic species in excess, and adsorb significant amounts of protein by electrostatic interactions. We modulated the bovine serum albumin net charge by pH and dealt with its binding on the aforementioned vesicles. Binding is controlled by the net charge of vesicles and albumin: it is substantial when the protein has negative charges in excess and is negligible below its isoelectric point. For pH values > 6.0, the binding efficiency increases in proportion to protein charge. Surface coverage changes in proportion to pH, when the number of charges neutralized upon binding remains grossly the same. The size of protein-vesicle lipoplexes was inferred by Dynamic Light Scattering and the effective charge by ζ-potential, whereas the state of albumin by Circular Dichroism. The results indicate that the conformation of adsorbed albumin is not much different from that in the bulk, in the same pH conditions. Attempts to determine the binding efficiency were made by elaborating surface charge density values, inferred by ζ-potential ones. The results were interpreted in terms of a Gibbs adsorption isotherm. Accordingly, it was possible to calculate the binding energy in different pH conditions.

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Hyaluronan based hydrogels as drug delivery system for catanionic sugar-derived surfactants Ferran Roig 1; Muriel Blanzat 2; Conxita Solans 3; Jordi Esquena 3; MªJosé García-Celma 1 1Universitat de Barcelona, Farmacia i Tecnologia Farmacèutica, R+D Unitat associada al CSIC, Barcelona, Spain; 2Université Paul Sabatier, Laboratoire IMRCP, UMR CNRS 5623, Toulouse, France; 3Consejo Superior de Investigaciones Científicas (CSIC), Institut de Química Avançada de Catalunya (IQAC), Barcelona, Spain

Hyaluronan (HA) is a natural polysaccharide widely distributed into the human body. Its physicochemical properties and the high biocompatibility make it as good candidate for biomedical and pharmaceutical use (1). In the present work a composed drug delivery system for the administration of ketoprofen, an anti-inflammatory drug, has been obtained. A sugar-derived surfactant associated with ketoprofen was prepared and incorporated into Hyaluronan based hydrogels. Sugar-derived surfactants are biocompatible, biodegradable and economic to obtain. Furthermore, the catanionic surfactants obtained of the association between a sugar-derived surfactant and ketoprofen allow greater solubilization of ketoprofen. That supramolecular association due to its amphiphilic character represents a suitable drug delivery system due to those characteristic properties. Hyaluronan based hydrogels were developed using a Butanediol Diglycidyl Ether as crosslinking agent. The association between a glucose derived surfactant, GHyd12, and ketoprofen was obtained by acid-base reaction (2,3). The physicochemical properties of catanionic surfactant obtained by the association between GHyd12 and ketoprofen have been studied. The tensiometric and dynamic light scattering (DLS) studies showed the formation of the aggregates of catanionic surfactant, GHyd12/Ketoprofen, in aqueous solution. The GHyd12/Ketoprofen aggregates were also characterized by TEM (Fig.1). The profile release of GHyd12/Ketoprofen from Hyaluronan based hydrogels show differences as a function of the value of concentration of catanionic surfactant in aqueous solution, below and above the value corresponding to the critical aggregation concentration (CAC). References: (1) Lapèík L., Lapèík L.Jr., De Smedt S., Demeeste J. Chemical Review. 1998; 98:2663-2684. (2) Blanzat M., Perez E., Rico-Lattes I., Prome D., Prome J.C., Lattes A. Langmuir 1999; 15:6163-6169. (3) Consola S., Blanzat M., Perez E., Garrigues J. C., Bordat P., Rico-Lattes I. Chem.Eur. J. 2007, 13(11), 3039-3047.

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Rheology of wormlike micelle formed by CTAB and different aromatic co-solutes Thiago Ito ; Paulo Miranda ; Edvaldo Sabadini University of Campinas, Chemisty Institute, Campinas, Brazil

The wormlike micelles (WLM) are one between the several self-assembly arrangements that surfactants molecules can assume in aqueous solution. The addition of some aromatic co-surfactants, such as salicylate, to cationic surfactants solutions, promotes the growing of such elongated micelles. In some cases the contour length of the WLM reaches values of hundreds of nanometers. The growing is due to the insertion of the aromatic molecules into the palisade of the micelle. Such process changes the critical packing parameter and thus, the curvature of the micelle. The sphere-to-rod transition is highly sensitive to the chemical structure of the aromatic, and this aspect is explored in this work. There are few studies correlating properties of the WLM and the molecular structure of the aromatic co-solutes. In this study, we present rheological studies for WLM formed with cetyltrimethylammonium bromide (CTAB) and several aromatic co-solutes, derivate of benzoate and cinnamate, phenol, tosylate. Our objectives here are to rationalize the rheology of wormlike micelles, by systematically varying the architecture of the aromatic co-solutes. The values for the elastic and viscous moduli and the relaxation time ((τR), for the gels formed by the mixture of 200 mmol L-1 of CTAB and 200 mmol L-1 of: sodium benzoate (BENZ) sodium ortho-methoxy benzoate (MBEZ), sodium salicylate (SALI), sodium cinnamate (CINN), sodium ortho-methoxy cinnamate (OMCA), sodium ortho-hydroxy cinnamate (OHCA), phenol (PHEN), sodium tosylate (TOSY), were determined. The following sequence τR were observed: OHCA > PHE 0, except for BENZ and PHE, is practically the same for the gels and this indicates that the co-solutes are forming with CTAB, WLM system with approximately the same network mesh size. Acknowledgments: CNPq, CAPES and Petrobras

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Spontaneous internalization of protein transduction domain into giant unilamellar vesicle by membrane curvature modulation Kazutami Sakamoto 1; Haruka Kuwahara 2; Kenichi Aburai 2; Kenichi Sakai 2; Hideki Sakai 2; Masahiko Abe 2; Shiroh Futaki 3; Taku Morishita 2 1Chiba Institute of Science, Pharmacy, Choshi, Japan; 2Tokyo University of Science, Faculty of Science and Technology, Noda, Japan; 3Kyoto University, Institute of Chemical Research, Uji, Japan

It is well known that a group of short peptides called Protein Transduction Domain (PTD) is able to spontaneously penetrate through bio-membrane although the mechanism remains to be explored1). Previously we have proven that membrane penetration of PTD is dependent on the membrane curvature2). First evidence of it is that PTD changes membrane curvature toward positive (from Lα phase to V1 then to H1 phase) by SAXS measurement. Second evidence is that the amount of internalized PTD increased by changing membrane curvature of erythrocyte toward positive by osmotic pressure modulation. On the basis of these results, we further evaluated the effect of membrane curvature for the PTD internalization to the giant unilamellar vesicle (GUV) by changing osmotic pressure. FITC-R8 was used as PTD with fluoreccence probe. As expected, amount of PTD internalized was increased with the osmotic pressure reduction which increase membrane curvature. Under the same conditions, FITC alone without PTD (R8) could not penetrate in. Furthermore, Rhodamin pre-encapsulated in the GUV would not leak out which confirms intact barrier function of membrane during the experiment. As a result, spontaneous PTD internalization can be described as a local and dynamic phase transition of membrane from Lα to mesh1 induced by PTD. To confirm this mechanism further, we tried the effect of lipid mobility by conducting the same experiment at the temperature under the liquid crystalline/gel phase transition where lipid molecule would not easily move to change membrane curvature even at the PTD's approach. As expected, FITC-R8 (as PTD) did not penetrate into GUV. This is because PTD cannot induce local and dynamic phase transition from Lα to Mesh1 because system is under the gel phase. Further details of mechanism and aditional trials will be shown at the presentation. 1) S. Futaki et al, ACS Chem. Biol. 1(5) (2006) 299 2) K. Sakamoto, J. Patent 2005-154413; ICAM2011

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Probing oil-surfactant interaction in oil-in-water emulsions using Sum-Frequency-Scattering-Spectroscopy Rüdiger Scheu ; Kailash C. Jena ; Hilton B. de Aguiar ; Sylvie Roke Ecole Polytechnique Federal de Lausanne, Laboratory for Fundamental Biophotonics, Lausanne, Switzerland

The properties of emulsion systems are mainly determined by their interfacial structure. Emulsions are in a metastable state whose lifetime is strongly depending on the presence of stabilizing surfactant molecules at the interface between the usually immiscible liquids. It is thus of great interest to specifically probe the interface with a molecular resolution. Vibrational Sum-Frequency-Scattering (V-SFS) is both chemically specific as well as inherently interface-sensitive and can be used to probe droplets/particles of sub-micron-size in-situ. Here we employ V-SFS to study the oil-surfactant interaction of common surfactants sodiumdodecylsulfate (SDS) and dodecyltrimethylammoniumbromide (DTAB) in oil-in-water emulsions. The ratio of the amplitudes of symmetric stretch modes of the methyl- and the methylene group is used as an indicator of conformational order of interfacial molecules. We will present how the structure of the head groups of the surfactants determines the oil-surfactant interaction and show supporting measurements of surfactants on polytetrafluoroethylene and polystyrene particles. Additionally, time domain experiments with a resolution of 100 fs were used to probe the vibrational relaxation of the water molecules surrounding the surfactants.

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Lanthanide containing lyotropic liquid crystal based on surfactants: complexation, structure and phase behavior Natalia Selivanova ; Oxana Shikhobalova ; Yury Galyametdinov Kazan National Research Technological University, Physical and Colloid Chemistry, Kazan, Russian Federation

Lyotropic metallomesogens containing trivalent rare-earth metal ions have unique attractive behavior due to combination of some specific properties of the lanthanide ions with anisotropic supramolecular organization liquid crystal and provide new promises in biochemistry and materials science. LLC have been potential applications in areas of porous material templating, as contrast agents in medical imaging, biorelevant systems for drag delivery. In this work presents the synthesis and study of physicochemical properties of the LLC on the basis of non-ionic surfactants – decaethylene glycol monododecyl ether C12H25O(CH2CH2O)10H (Ñ12ÅÎ10), tetraethylene glycol monododecyl ether C12H25O(CH2CH2O)4H (Ñ12ÅÎ4), zwitterionic surfactant - N,N- dimethylaminooxide (CH3(CH2)11N(O)(CH3)2) (C12DMAO) and hydrated lanthanide nitrates Ln(NO3)3 6H2O, Ln = La, Eu, Tb, Gd in water and water-decanol environments. The investigation of phase behavior was shown that the systems C12EO10/LnIII/H2O form hexagonal mesophase, and the C12EO4/LnIII/H2O systems form lamellar mesophase. The C12DMAO/LnIII/decanol systems depending on the molar ratio forms different types of mesophases: hexagonal, lamellar and nematic in various concentrations regions. The phase diagrams were constructed; the temperature and concentration limits control the type of supramolecular organization were defined. The geometric parameters were determined by SAXS. In the C12EO10/LnIII/H2O and C12EO4/LnIII/H2O systems the variation of structural parameters of the mesophases depending on the water content in the system was shown. According from the IR spectroscopy data the formation of the LC complex of the lanthanide ion with the oxyethylated groups of the surfactant was established. The hydration extent of the first coordination sphere of the EuIII and TbIII ions in the liquid-crystal state were estimated from the luminescence lifetime data. The work was supported by the RFBR 11-03-00679-à.

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The effect of fluorocarbon/hydrocarbon miscibility on microstructure, phase behavior, and emulsification of Tween 80/oil/water systems Suraj Sharma ; Gregory Warr The University of Sydney, School of Chemistry, Sydney, Australia

Polyoxyethylene (20) sorbitan monooleate (Tween 80) is a biocompatible nonionic surfactant widely used as emulsifier in food, cosmetics, and pharmaceutical industries. Although there are numerous studies on the formulation and characterization of microemulsions using such food grade surfactants and cosurfactants, but the structural details of microemulsions formed at high Tween 80/oil ratio is not well understood, and the effect of oil solubilization on the aqueous phase behavior of Tween 80 and its role in the emulsification of lyotropic liquid crystals is likewise relatively unexplored. In this context, we have studied the phase behavior, microstructure, and emulsification characteristics of ternary mixtures of Tween 80 with water and d-limonene (LM) or perfluoromethyldecalin (PFMD) by small-angle X-ray scattering and polarizing optical microscopy. In the Tween 80/water binary system, a micellar solution (L1), a hexagonal (H1) phase, and a surfactant liquid or inverted micellar solution (L2) are successively formed at 25 °C. LM can be solubilized into all the phases formed by Tween 80/water mixtures, whereas no solubilization of PFMD occurs. The L2 phase was found by small-angle neutron scattering to be bicontinuous with low interfacial curvature. Added water swells and amplifies the pre-existing amphiphilic structure. A Tween 80/water hexagonal liquid crystal can be used to emulsify a large amount of PFMD, yielding stable liquid crystal emulsions.

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Langmuir monolayer behavior of partially fluorinated alcohols (F8HmOH) and dipalmitoylphosphatidylcholine (DPPC) Hiromichi Nakahara 1; Chikayo Hirano 1; Seiichi Sakamoto 1; Marie Pierre Krafft 2; Osamu Shibata 1 1Nagasaki International University, Department of Biophysical Chemistry, Faculty of Pharmaceutical Sciences, Sasebo, Nagasaki, Japan; 2Institut Charles Sadron (CNRS, UPR 22), Systemes Organises Fluores a Finalites Therapeutiques (SOFFT), Strasbourg, France

Langmuir monolayers at the air-water interface are a paradigm of biomembranes and pulmonary surfactants for investigating physicochemical interactions between biomembrane components with fluorinated amphiphiles. They have effectively been employed for a better understanding of miscibility, interaction, and phase behavior of binary mixtures of the components and synthetic amphiphiles. So far, however, few articles have discussed the interaction of partially fluorinated compounds with biomembrane lipids in the Langmuir monolayers. Herein, the molecular behavior of perfluorooctylated fatty alcohols (F8HmOH, n = 5, 7, 9, and 11) with dipalmitoylphosphatidylcholine (DPPC) was evaluated at the air-water interface. It is getting clear that F8HmOH is (partially) miscible with DPPC in the binary monolayer state. The two-dimensional phase diagrams were constructed by plotting the surface pressure of phase transitions against the molar fraction (XF8HmOH). An interaction parameter and interaction energy were evaluated under the assumption of a regular surface mixture. In addition, the excess Gibbs free energy of mixing for the systems used here was calculated on the basis of the additivity rule. Morphological observations with BAM, FM, and AFM also support two-component miscibility on the micro- and nanometre scales. These characterization is based on Langmuir monolayers should help clarify the biophysical role of pulmonary surfactants and lipid rafts[1,2]. References: [1] S. Nakamura, H. Nakahara, M.P. Krafft, O. Shibata, Langmuir 23, 12634-12644 (2007). [2] H. Nakahara, M.P. Krafft, A. Shibata, O. Shibata, Soft Matter 7, 7325-7333 (2011).

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Photoinduced viscosity change in mixtures of an anionic photoresponsive amphiphilic compound and a cationic surfactant solution Yutaka Takahashi ; Yuki Yamamoto ; Yukishige Kondo Tokyo University of Science, Tokyo, Japan

A number of researchers have studied the control of the formation and disruption of wormlike micelles by light. According to their reports, wormlike micelles are disrupted by UV light irradiation, and then reformed by visible light irradiation. However, there are very few studies concerning the opposite change to such light-responsive behavior. In this study, we succeeded in reversibly forming wormlike micelles by UV light irradiation and disrupting them by visible light irradiation for the mixtures of sodium [4-(4-butylphenylazo)phenoxy]acetate (C4AzoNa) and cetyltrimethylammonium bromide (CTAB) in water. In this paper, we report the details of the wormlike micelle formation and the mechanisms of the formation and disruption of the wormlike micelles by light irradiation. UV/Vis measurements indicated that UV light irradiation of an aqueous solution of CTAB/C4AzoNa (100 mM/35 mM) for at least 180 min led to the photostationary state of cis-isomer for C4AzoNa. Subsequent visible light irradiation for 30 min caused conversion of cis-C4AzoNa into trans-C4AzoNa. The CTAB/trans-C4AzoNa mixture was a low-viscosity fluid, and the zero-shear viscosity for the aqueous mixtures was ca. 0.01 Pa s. When the UV light was irradiated to the mixture of CTAB and trans-C4AzoNa, the mixture became a highly viscous gel. The value of zero-shear viscosity for the mixture was ca. 10 Pa s, the value of which is 3 orders of magnitude higher than the viscosity of the CTAB/trans-C4AzoNa mixture. Measurements of the frequency dependence of dynamic viscoelasticity indicated the formation of wormlike micelles in the CTAB/cis-C4AzoNa mixture but not in the CTAB/trans-C4AzoNa mixture. Therefore, we concluded that geometric structural transformation of the azobenzene groups of C4AzoNa in the CTAB/C4AzoNa mixture would lead to drastic viscosity changes, thereby inducing the formation and disruption of wormlike micelles.

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Solubilization of two organic dyes by cationic ester-containing gemini surfactants Ali Reza Tehrani-Bagha ; Rajdeep G. Singh ; Krister Holmberg Chalmers University of Technology, Department of Chemical and Biological Engineering, Göteborg, Sweden

Solubilization of two different types of organic dyes, Quinizarin with an anthraquinone structure and Sudan I with an azo structure, has been studied in aqueous solutions of a series of cationic gemini surfactants and of a conventional monomeric cationic surfactant, dodecyltrimethylammonium bromide (DTAB). Surfactant concentrations both above and below the critical micelle concentration were used. The concentration of solubilized dye at equilibrium was determined from the absorbance of the solution at λmax with the aid of a calibration curve. The solubilization power of the gemini surfactants was higher than that of DTAB and increased with increasing alkyl chain length. An increase in length of the spacer unit resulted in increased solubilization power while a hydroxyl group in the spacer did not have much effect. Ester bonds in the alkyl chains reduced the solubilization power with respect to both dyes. A comparison between the absorbance spectra of the dyes in micellar solution with spectra in a range of solvents of different polarity indicated that the dye is situated in a relatively polar environment. One may therefore assume that the dye is located just below the head group region of the micelle. Attractive π-cation interactions may play a role for orienting the dye to the outer region of the micelle.

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Growth of gold nanoparticles using cationic gemini surfactants: effects of structure variations in head and tail groups Titoo Jain 1; Ali Reza Tehrani-Bagha 2; Kasper Nørgaard 1; Krister Holmberg 2; Kasper Moth-Poulsen 2 1University of Copenhagen, Copenhagen, Denmark; 2Chalmers University of Technology, Department of Chemical and Biological Engineering, Göteborg, Sweden

Anisotropic noble metal nanostructures are of general interest due to their interesting optical and physical properties. Gold nanorods have found application in materials and optics, including polarizers, filters, and to improve the storage density in compact disks. In this study, a library of cationic gemini surfactants is employed to study surfactant directed anisotropic growth of gold nanoparticles. The variables in the chemical structure of these geminis were: (a) the alkyl chain length , (b) the spacer length, (c) the presence of an ester bond in the alkyl tail, and (d) the presence of a hydroxyl group in the spacer. The experiment showed that the anisotropic growth is highly susceptible to small changes in the chemical structure of the surfactant. The yield of rod-shaped gold nanoparticles for the majority of cationic gemini surfactants was above 55% with aspect ratios ranging between 1.5 and 2.5. Using ester-containing surfactants which are susceptible to alkaline hydrolysis is one approach to remove and replace the surfactant with another organic molecule on the surface of gold nanorods for delivery and other medical applications.

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Between peptides and bile acids: extremely narrow nanotubes by self-assembly of amino acid-substituted cholic acid Leana Travaglini 1; Andrea D'Annibale 1; Ulf Olsson 2; Karin Schillen 2; Simona Sennato 3; Nicolae V. Pavel 1; Luciano Galantini 1 1Università di Roma Sapienza, Dipartimento di Chimica, Roma, Italy; 2Lund University, Physical Chemistry 1, Lund, Sweden; 3Università di Roma Sapienza, Dipartimento di Fisica e CNISM, Roma, Italy

The self-assembly of biocompatible molecules is of great importance in biological and medical applications of nanoscience. Peptides have been extensively investigated because of their ability to form several supramolecular structures (e.g. gels, fibers, ribbons and tubules), sometimes showing an external-stimuli responsiveness. Bile acids, due to their particular amphiphilic backbone, act as peculiar surfactants with important biological functions. Recently it was showed that their self-assembly behavior can be significantly varied by introducing relatively small modifications of the molecular structure.[1,2] It is known that the organization of aggregates formed by peptides or bile salts is determined by the combined effect of several forces, such as hydrogen bonds, hydrophobic forces and π-π stacking interactions. That said, the aim of this study was the preparation of a new class of biocompatible molecules that would combine both bile salts and peptides properties and that might be used in biomedical applications. We synthesized a zwitterionic amino acid-cholic acid derivative, bearing a phenylalanine amide subunit at steroidic C-3. In our purpose such a compound could mix in itself both the self-associative behavior of bile acid, strongly biased by the steroidic skeleton, and the wide range of pH sensitivity, typical of peptides. The aggregation behavior has been investigated using CD, DLS, SAXS, UV absorption, AFM, surface tension measurements in combination with Cryo-TEM. In agreement with our expectations, our derivative showed very interesting aggregation patterns, strongly dependent upon experimental conditions. [1] N. Manghisi, C. Leggio, A. Jover, F. Meijide, N.V. Pavel, V. H. Soto Tellini, J. Vázquez Tato, R. G. Agostino, L. Galantini Angew. Chem. Int. Ed. 2010, 49, 6604 [2] L. Galantini, C. Leggio, A. Jover, F. Meijide, N.V. Pavel, V.H. Soto Tellini, J.V.Tato, R. Di Leonardo, G. Ruocco Soft matter, 2009, 5, 3018.

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Bending rigidity of a diblock copolymer monolayer containing weak polyelectrolyte subchains and pH-induced shape transitions of copolymer's aggregates in solution Alexey Victorov, St.Petersburg State University, Department of Chemistry, St.Petersburg, Russian Federation

Bending rigidity of amphiphilic membranes is important in many different phenomena, including microemusion stability, shape transitions of self-assembled structures, and spatial organization and physiological functions of biological cells. Bending rigidity of a membrane is quantified by the elasticity constants in the curvature expansion of the free energy. For a membrane formed by weak polyelectrolyte, to the best of our knowledge there has been no derivation of the elasticity constants from a microscopic model. In this work analytical description has been given to a change produced by curvature deformation of a weak polyelectrolyte brush. We describe slow deformations that maintain equilibrium spatial distribution of species in the swollen brush and the mechanical equilibrium between the brush and the surrounding solution. From the model of a boxlike brush we derive the profiles and the thickness of the curved brushes in terms of properties of a planar brush. We show that slowly bent brushes always take some solvent up. This uptake depends on the osmotic compressibility of the brush. We describe the effect of deformation on the local degree of dissociation in the weak polyelectrolyte brush. We show that the curvature expansion of the free energy yields reliable prediction of shape transitions in response to variation of pH and salinity for crew-cut diblock copolymer aggregates of different shape including lamellae, Y-shaped branched structures, cylinders, and spherical micelles. For a membrane that consists of a dry hydrophobic brush and a swollen polyelectrolyte brush, we study the effects of the acidity and salinity of the environment on the curvature elasticity and on the location of the surface of inextension. Nontrivial mechanical behavior of the membrane is predicted for pH around pK in the physiological salinity interval. Financial support from the RFBR (project #12-03-00977-à) and from Saint Petersburg State University (project #12.37.127.2011) is acknowledged.

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Aggregation of nonionic N-oxide surfactants; experimental and computational approaches Kazimiera A. Wilk 1; Agnieszka Lewinska 2; Maciej Witwicki 2; Adam Jezierski 2 1Wroclaw University od Technology, Organic and Pharmaceutical Technology Group, Faculty of Chemistry, Wroclaw, Poland; 2University of Wroclaw, Faculty of Chemistry, Wroclaw, Poland

We have studied an interesting subclass of N-oxide surfactants, containing one hydrophobic part and hydrophilic oxidized amino moieties. Owing to their excellent surface and performance properties, insignificant adverse environmental impact and the fact that they can be synthesized from renewable materials, such surfactants can provide numerous new opportunities. The main aim of the present studies was a broad characterization of the aggregation state of 2-(alkanoylamino)ethyldimethylamine-N-oxides, and 3-(alkanoylamino)-propyldimethylamine N-oxides surfactants by experimental (EPR, DLS) and theoretical (DFT and QSAR) methods. The use of two different nitroxide probes allowed to explore different regions of investigated micellar systems and in consequence brought an insight into local microenvironment by characterizing the polarity, viscosity, hydration and degree of order. By monitoring of rotational correlation times as a function of surfactant concentration, the critical micelle concentrations (CMC) were determined and subsequently compared to the values obtained by tensiometry. DLS methods allowed to estimate the size of micellar aggregates and polydispersity indices. In addition, hydrodynamic radii and micelle volumes were determined from DLS measurements. Further analysis of structural properties was performed employing in silico techniques. The structures of formed aggregates, defined by the critical packing parameter, were predicted with the QSAR approach and hydrodynamic radii, micellar volumes and their aggregation numbers were computed with the long range corrected B3LYP hybrid functional. A good agreement between theory and experiment was reached. Our results proved great effectiveness of the spin probe method for investigation of micelle formation and microenvironment as well as the usefulness of the DLS, QSAR and DFT techniques for evaluation of the interfacial and aggregation behavior.

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Structural characterization of systems formed by different cationic surfactants and anionic-neutral block copolymers Letícia Vitorazi 1; Watson Loh 1; Jean François Berret 2 1University of Campinas (UNICAMP), Institute of Chemistry, Campinas, Brazil; 2Université Denis Diderot Paris-VII, Matière et Systèmes Complexes, Paris, France

It is well-known that block copolymers with neutral and charged blocks forms aggregates called “colloidal complexes” in the presence of surfactants of oppositely charged. Within the core of these aggregates there are surfactants micelles surrounded by polyelectrolyte, while the neutral chains of the copolymer form the shell. From SAXS curves of complexes formed by poly(acrylic acid)-b-polyacrylamide (PAH-b-PAm) and dodecyltrimethylammonium bromide (DTAB) surfactant, a broad peak is observed around 1.6 nm-1, or a characteristic distance of 4.0 nm, ascribed to the micelles inside the core, which are not in an ordered array. An important question concerning the core arrangement of these structures has being made: “Is the core a disordered microphase of micelles or is it an ordered phase with Bragg reflections broadened by the reduced size of the crystallite domains?” Many studies have been conducted with the direct mixing of polymer and surfactant solutions, describing the structure, mechanism, and the thermodynamic properties of the complexes formed in aqueous solution. Using an alternative method developed by Picullel’s research group, aqueous samples free of small counter ions, were prepared, and results show an organized core with micelles sorted in a cubic array when DTAB surfactant was used and a hexagonal array when CTAB was used Increasing the concentration of salt complex in water, the phase transition from cubic to hexagonal array was observed for the systems PAH-b-PAm/DTAB. Samples were submitted to anneling treatment and the unit cell size for cubic array did not change as an indicative of equilibrium condition of micelles in the core. The addition of excess polyelectrolyte leads to disorder of the aggregate core. Another way of changing the internal array of these complex structures is by adding a third component such as a co-solvent and co-surfactant (n-alcohol).

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Phase behavior of microemulsions with weak and strong surfactants Harsha Paroor ; Doris Vollmer MPI for Polymer Research, Mainz, Germany

Microemulsions are thermodynamically stable isotropic mixtures of water, oil and surfactant with unique properties like ultralow interfacial tension, large interfacial area and the ability to solubilise other immiscible liquids. Depending on temperature and concentration, surfactant molecules associate into a micellar, lamellar, hexagonal or sponge like bicontinous structure. The local curvature of the surfactant molecule largely determines the structure of microemulsions. Microemulsions can have three different macroscopic phases (a) isotropic , (b) 2-phase with oil/ water emulsified out of the microemulsion (c) 3-phase with oil and water emulsified out of the microemulsion [1]. A quantitative prediction of the phase diagram of non-ionic microemulsion is presented here. Due to the conservation of the components, in a 1-phase the droplet size is determined by composition [2], whereas in 2-phase it is determined by temperature due to the temperature dependence of the spontaneous curvature c0(T). The dependency of the droplet size on c0(T) can be explained with Helfrich bending free energy density. However this approach cannot account for the 3-phase region. Therefore we proposed a modified Helfrich equation describing all the three macroscopic phases [3]. It assumes that within a well-defined temperature interval two spontaneous curvatures coexist. To investigate the validity of this assumption we investigate the phase boundaries by various measurements. Spontaneous curvature plots calculated from fitting the emulsification boundaries sheds light to the coexistence of two curvatures over a wide range of temperature and surfactant concentration. Experimentally determined values for the phase transition temperatures and specific heat have been successfully fitted to the unified model. Our experiments lead to a clear picture of the validity of the modified Helfrich free energy for a wide range of surfactants and phase transitions in these systems [4]. [1] M.Kahlweit, R.Strey and G.Busse, Phys. Rev. E 47 (1993), 4197-4209. [2] M. Daoud, C.E. Williams, Soft Matter Physics, Springer Verlag, Berlin (1999) [3] H. Paroor, D.Vollmer, in preparation

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Fluctuation measurement of free-standing bilayer lipid membranes by laser-induced surface deformation spectroscopy Tatsuya Yaguchi 1; Taro Toyota 2; Tomonori Nomoto 1; Masanori Fujinami 1 1Chiba University, Chiba, Japan; 2The University of Tokyo, Tokyo, Japan

Free-standing bilayer lipid membranes (BLMs) are well-known as one of the biomembrane models and have been extensively investigated their static and dynamic properties. BLMs thermally fluctuate at various frequency-modes, that strongly depend on their surroundings and the external stimulation. Therefore, to evaluate the fluctuation of BLMs is very important for the elucidation of their physiological functions. We have constructed the optical system of laser-induced surface deformation spectroscopy (LISD), which can measure an interfacial tension of a liquid/liquid interface in a non-contact manner. In this study, we aim to measure the membrane tension of the BLMs by LISD and discuss their fluctuation. For LISD, we measure modulation frequency dependence on the deformation of interface induced by radiation pressure of laser beam at the interface. The interfacial displacement excited by the pump laser can be estimated by a deflection of another probe laser. The motion of the interface in response to the modulated intensity of the pump laser shows a characteristic spectrum yielding an accurate value of the interfacial tension. BLMs were made by applying a decane solution dissolving egg york phosphatidylcholine and cholesterol (molar ratio 1:1) to a teflon foil with a 1-mm diameter hole in 100 mM KCl solution. To deform the BLMs by radiation pressure, the refractive index were adjusted by addition of different sugar solutions into both of the water phases. We have succeeded in the acquisition of the LISD signal considered to be thermally fluctuation of BLMs. From analyzing the LISD data, the membrane tension of BLMs was estimated to be around 10 nN/m. It has been proven that LISD is a promising tool to investigate their dynamic behavior. Since the fluctuation of the BLMs depends on the chemical composition and the association of membrane proteins, LISD will be applied to clarify the relationship between the fluctuation and the function.

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TUESDAY

Tuesday 4 Sept: Poster presented 17.00-18.00 P2:1

Investigation of the stability of depletion-flocculated emulsions using creep measurements and diffusive wave spectroscopy (DWS) Simon Aben 1; Christian Holtze 2; Tharwat Tadros 3; Peter Schurtenberger 4 1BASF SE / Adolphe Merkle Institute, University of Fribourg, GVM/F, Ludwigshafen, Germany; 2BASF SE, GVM/F, Ludwigshafen, Germany; 389 Nash Grove Lane, Wokingham, United Kingdom; 4Lund University, Physical Chemistry, Department of Chemistry, Lund, Sweden

Distinguishing stable samples from unstable ones remains an important scientific and industrial challenge. To address this issue, paraffin oil (Isopar V) in water model emulsions were prepared using an ABA-block co-polymer stabilizer of PEO-PPO-PEO (Pluronic® PE 6400). The effect of the addition of a non-adsorbing polymer (xanthan gum, Mw = 2.88 106 g mol-1) on the creaming of emulsions at high volume fraction (øoil = 0.5) was investigated as a function of concentration of xanthan gum. The addition of xanthan gum at concentrations of 0.1% and less enhanced the emulsion creaming as a result of depletion flocculation, whereby the flocculated structure was not sufficiently strong to eliminate creaming. Above 0.25% xanthan gum a gel network could be produced that caused arrest of the emulsion droplets in the gel network, and therefore no phase separation was obtained. In this presentation we will describe the results of a systematic investigation using steady-state and oscillatory rheology, diffusing wave spectroscopy (DWS) and confocal laser scanning microscopy (CLSM). We present evidence for a direct link between the structure of the network formed (from CLSM), its local (from DWS) and macroscopic (from rheology) viscoelastic properties such as the relaxation time and the magnitude of the elastic modulus, and the long-term macroscopic stability of the samples.

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P2:2 Tuesday 4 Sept: Poster presented 18.00-19.00

Crystalline nanoparticle dispersions do not ripen Manja Behrens 1; Urban Skantze 2; Lennart Lindfors 2; Ulf Olsson 1 1Lund University, Department of Chemistry, Lund, Sweden; 2Pharmaceutical and Analytical R & D, Experimental Formulations, AstraZeneca R&D Mölndal, Mölndal, Sweden

Understanding and controlling the behavior of dispersed nanoparticles, both crystalline and amorphous, is of great importance for their application in drug formulations and also for shedding further light on fundamental questions regarding molecular exchange processes at crystalline surfaces. Here, the focus is on Ostwald ripening of nanoparticles. The ripening in crystalline and amorphous nanoparticles dispersions have been studied, using time resolved light scattering methods. While amorphous particles undergo classical Ostwald ripening1, governed by an interfacial tension and the monomer solubility and diffusion coefficient, the crystalline dispersions do not. Rather, their size distributions remain essentially stationary in time. Data from three different compounds are presented and the molecular origin of the observations is discussed. Furthermore, the particles have also been investigated by TEM. 1 Lindfors et al (2006) Langmuir 22, 906-910

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Agglomeration in sterically stabilized nanoparticle suspensions revisited Philip Born ; Tobias Kraus Leibniz Insitute for New Materials, Structure Formation on Small Scales, Saarbrücken, Germany

Sterically stabilized particle suspensions with weak dispersion attractions of the cores and long ligand chains are usually well-described by the flocculation or θ-temperatures of the stabilizing polymeric ligand chains. For colloidal particles with strong dispersion interactions of the cores and short stabilizing ligands, as they often occur in technologically relevant nanoparticles, this exclusive focus on the ligand chains seems insufficient. A better understanding of their agglomeration kinetics will help identifying the parameters that govern the stability of such suspensions. Here, we investigate the stability and agglomeration kinetics of unpolar gold nanoparticle suspensions stabilized by thin alkyl thiol shells with 12 to 18 carbon atoms in the alkane backbone. All of these suspensions agglomerate below a critical temperature that increases with ligand chain length. The effective interaction among the particles, obtained from small-angle synchroton x-ray scattering measurements, was compared to the agglomeration kinetics observed in dynamic light scattering. At the critical temperature, the interaction strength drops below -3/2 kT and reaction-limited agglomeration sets in. Further cooling leads to a further drop in the interaction potential depth by several kT and the agglomeration becomes diffusion-limited. We conclude that agglomeration in such suspensions is driven by the solubility of and phase changes in the ligand shell rather than core-interactions. This holds even for very short ligand chains. The agglomeration behaviour can be characterized in analogy to charge stabilized suspensions using temperature-dependent stability ratios in the reaction-limited regime and temperature-independent stability ratios in the diffusion-limited regime. Similarly, the continued growth of the agglomerates follows power and exponential laws known from charge stabilized suspensions. However, rate constants indicate deviations from pure Smoluchowskian agglomeration.

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Influence of the polymer size on depletion attraction-induced gel and glass transitions of microgel colloids Carl Stilke ; Stefanie Burger ; Eckhard Bartsch University of Freiburg, Department of Physical Chemistry, Freiburg, Germany

Introducing short-ranged depletion attraction by addition of non-adsorbing (“free”) polymer to colloidal dispersions has two effects: at low colloid volume fractions φ transient gel states are introduced; at high φ the glass transition is shifted to higher values and an attractive glass line emerges which meets the receding repulsive glass line leading to a fluid pocket at intermediate polymer concentrations. The latter behaviour was first predicted by theory [1,2] and then experimentally observed for several systems, among them a binary mixture of polystyrene (PS) microgel colloids [3]. As this re-entry effect allows to prepare highly concentrated, yet freely flowing colloidal dispersions we explored this effect by systematically changing the depletion attraction range δ = Rg,polymer/Rh,colloid from 0.08 to 0.03 by varying the polymer molecular mass. We find that a decrease of φ from 0.08 to 0.059 shifts the maximum volume fraction of fluid states significantly from 0.69 to 0.72 in qualitative agreement with theory [2]. At a further decrease to δ = 0.03 no attractive glass transition at high polymer concentration occurs anymore, possibly due to osmotic deswelling of the microgel colloids. At lower volume fractions φ < 0.5 a kinetic arrest is observed leading to transient gel states. The gel line is shifted to higher polymer concentrations with decreasing attraction range δ. The extension of these gel lines matches at high φ with the attractive glass lines in agreement with theoretical predictions [1]. In order to determine the interaction strength needed to induce gelation we corrected polymer concentration and polymer osmotic pressure for polymer non-ideality according to Fleer etal. We find that the contact value calculated for an Asakura-Oosawa potential is independent of the colloid volume fraction between 0.1 and 0.6 and increases systematically with decreasing attraction range δ. [1] J. Bergenholtz, M. Fuchs, Phys. Rev. E 59, 5706 (1999) [2] K. Dawson et al., Phys. Rev. E 63, 1401 (2000) [3] T. Eckert, E. Bartsch, J. Phys.: Cond. Matter 16, 4937 (2004)

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Dense colloidal fluids form denser sediments Alexander V. Butenko 1; Shir R. Hochwald 1; Pilkhaz Nanikashvili 2; David Zitoun 2; Eli Sloutskin 1 1Bar-Ilan University, Physics Department and Institute for Nanotechnology and Advanced Materials, Ramat-Gan, Israel; 2Bar-Ilan University, Chemistry Department and Institute for Nanotechnology and Advanced Materials, Ramat-Gan, Israel

Disordered granular packings, where the constituent particles are immobilized by contacts with their neighbours, are abundant in the everyday life and industry and play a fundamental role in physics of granular matter. Moreover, such packings are widely believed to mimic some of the basic aspects of glass formation. Dense random packings of simple hard spheres were studied, both experimentally and theoretically, for several decades; however, the physical understanding of these systems is still very poor. In particular, many different experimental protocols indicate that disordered systems of hard spheres reach their maximal packing density when the spheres constitute 64% of the total volume of the system. However, the theoretical understanding of this so-called “random close packed” (RCP) state is still missing. We employ analytical centrifugation techniques and confocal microscopy to study non-crystalline colloidal sediments, prepared by centrifugation from a thermodynamically-equilibrated suspension of simple hard spheres. We demonstrate that our system allows the density and the entropy of these solid packings to be tuned in a controllable way by changing the density of the initial fluid. Moreover a critical packing density exists, where all fluid states in our suspensions get extinguished. This critical density coincides with the well known RCP limit, suggesting a theoretical definition of this limit to be established, based on our experimental observations.

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Colloidal gels under shear Ronja F. Capellmann 1; Kevin J. Mutch 1; Marco Laurati 1; Johan Bergenholtz 2; Stefan U. Egelhaaf 1 1Heinrich Heine University Düsseldorf, Department of Experimental Soft Matter Physics (IPkM), Düsseldorf, Germany; 2University of Gothenburg, Department of Chemistry and Molecular Biology, Gothenburg, Sweden

We study a system of hard-sphere colloids with a short-range attraction induced by the "depletion effect" of non-adsorbing polymers. Apart from the well-known equilibrium phases, liquid and crystal, these suspensions can form an arrested network-like structure called "gel", representing an example for a non-equilibrium state. We use colloid-polymer mixtures which consist of PMMA particles and polystyrene in a density-matched mixture of cis-decalin and cycloheptyl bromide. In this system we investigate the response of colloidal gels to shear which is applied by a rheometer determining the rheological response or by a shear cell observing structural changes. The structural changes in the sample can be observed by two complementary techniques: Small angle light scattering and confocal microscopy. The real time observations may contribute to a better understanding of the structural rearrangement of gels under shear.

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Effect of non-electrostatic physisorption on charge-regulated surface forces Vivianne Deniz ; Drew F. Parsons Australian National University, Applied Mathematics, Canberra, Australia

When ion-surface non-electrostatic interactions, such as dispersion, are included in a Poisson-Boltzmann model of colloidal interactions, an additional term due to those dispersion interactions must be included in the interaction free energy, with a corresponding contribution to the interaction force. This term is present for all boundary conditions commonly invoked to solve the Poisson-Boltzmann equation: constant charge, constant potential and charge regulation, and is the only new term present due to dispersion under constant charge conditions. However, under constant potential or charge regulated conditions, where the surface charge or potential is determined by an exchange of ions between solution and surface, a free energy term representing the chemisorption of the potential determining ion to the interface must also be included. The ionic dispersion potential here appears again due to a shift in the equilibrium condition balancing the chemical potentials of physisorbed and chemisorbed ions at the surface, Δµchemisorption + Δµphysisorption = 0, where now the dispersion potential contributes to the physisorption process Δµphysisorption = eφ0 + U0

disp. In this presentation we will account for what the implication of this is for the interaction force, which will no longer be described by the same formula under the three common boundary conditions, and what this might mean for the prediction of the surface charge density and surface potential.

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Silica-coated hematite nanoparticles using water-soluble polyalkoxysiloxanes Karla Doermbach ; Garima Agrawal ; Andrij Pich DWI an der RWTH Aachen e.V. and Institute for Technical and Macromolecular Chemistry of RWTH Aachen University, Aachen, Germany

Hematite nanoparticles are of increasing interest owing to their potential application in various fields ranging from photovoltaic, pigments, catalysis to biomedical applications like MRI contrast enhancement. Silica coating of these particles is crucial to enhance their dispersibility and stability in different media along with increasing biocompatibility and surface chemical functionality. Classical method for silica coating on hematite particles involves hydrolysis/condensation of TEOS in organic media combined with PVP adsorption. In our approach we use a water soluble silica precursor polymer- hyperbranched polyalkoxysiloxane (PAOS) - for the formation of silica shell. Synthesis and properties of silica-coated hematite particles with adjustable size and SiO2 shell thickness will be discussed in detail. Advantages of this method as well as potential application fields for composite colloids will be described. Acknowledgement: The authors thank VolkswagenStiftung for the financial support. References: [1]Ozaki, M.; Kratohvil, S.; Matijevic, E. Journal of Colloid and Interface Science, 1984, 102, 146-151 [2]Zhu, X.; Jaumann, M.; Peter, K.; Möller, M.; Melian, C.; Adams-Buda, A.; Demco, D. E.; Blümich, B. Macromolecules, 2006, 39, 1701.

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Protein conformation and aggregation in white wines: effect of physico-chemical parameters Marie Dufrechou 1; Aude Vernhet 1; Pierre Roblin 2; Francois-Xavier Sauvage 1; Céline Poncet-Legrand 1 1INRA, Montpellier, France; 2INRA, Gif sur Yvette, France

Proteins in white wines (15-300 mg/L) are responsible of instabilities [1, 2]. They are of interest for winemakers because they lead to the formation of haze which affects the visual quality of the product. To avoid this defect during wine bottle storage, a treatment is used to remove proteins (adsorption on clay particules). However, this non-specific treatment leads to non-negligible volume, aroma and color losses. The objective of the present study is to have a better understanding of the physico-chemical mechanisms and non-protein compounds (polysaccharides, polyphenols, ions…) involved in aggregation. Such information is needed to propose more selective and effective treatments. White wine is a complex medium with the presence of different protein isoforms and non-protein compounds. Therefore we decided to compare results in model wine systems (whole proteins) and real wine. Our results at room temperature highlighted that wine pH and ionic strength played a determinant part in aggregation mechanisms, aggregate characteristics, and final haze whereas non-protein compounds modulated aggregation [3]. Moreover, results emphasized a stronger colloidal instability at low pH. We hypothesized that at low pH the conformation of unstable proteins changed (far from protein isoelectric point), leading to aggregation. To study this phenomenon, different experiments were performed on purified stable and unstable protein isoforms. Specific methods such as differential scanning calorimetry, circular dichroism or small angle X-ray scattering were used on the tested proteins. Analyses of results enable us to determine that most protein isoforms were stable even at low pH. These results will be discussed. [1] Bayly, F. C. and H. W. Berg, Am. J. Eno. Viti. (1967) 18 (1): 18-32 [2] E.J. Waters et al., The Australian Journal of Grape and Wine Research 11 (2005) 215-225. [3] M. Dufrechou et al, J. Agric. Food. Chem., (2012), 60, 1308−1319

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DHS equations of state from slow analytical centrifugation in ultrathin capillaries Ben Erné ; Bob Luigjes ; Dominique Thies-Weesie ; Albert Philipse Utrecht University, Van 't Hoff laboratory for Physical and Colloid Chemistry, Utrecht, Netherlands

The concentration-dependent osmotic pressure of ferrofluids was determined from analytical centrifugation, by numerical integration of sedimentation equilibrium profiles. Because of the high buoyant mass of the magnetic colloidal particles, we made novel use of a slow analytical centrifuge [1], originally designed to study the sedimentation of paints and food emulsions. Moreover, the pitch-black ferrofluids were placed into ultrathin glass capillary cells [1], to ensure sufficient optical transmission. The sterically stabilized single-domain magnetic nanoparticles behaved as dipolar hard spheres (DHS), yielding the second virial coefficients theoretically expected from the magnetic dipole moment of the particles [2,3]. Our results demonstrate the feasibility of determining the equation of state of concentrated, strongly absorbing colloidal dispersions from slow analytical centrifugation in ultrathin capillaries. [1] B. Luigjes, D.M.E. Thies-Weesie, A.P. Philipse, B.H. Erné, J. Phys. Condens. Matter 24, 245103 (2012). [2] B. Luigjes, D.M.E. Thies-Weesie, B.H. Erné, A.P. Philipse, J. Phys. Condens. Matter 24, 245104 (2012). [3] A.P. Philipse, B.W.M. Kuipers, J. Phys. Condens. Matter 22, 325104 (2010).

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Particle dynamics in one- and two-dimensional random potentials Florian Evers ; Richard D. L. Hanes ; Stefan U. Egelhaaf Heinrich-Heine-University Dusseldorf, Dusseldorf, Germany

We experimentally studied the dynamics of individual colloidal particles in random potentials. Each local value of the one- or two-dimensional potentials was drawn from a Gaussian distribution, the width of which was varied between measurements. The random potentials were generated optically and the motion of the colloidal particles followed by video microscopy. The particle dynamics were studied over many orders of magnitude in time and characterised using the mean squared displacement, the van Hove function and the non-Gaussian parameter. The dynamics are initially diffusive, show an extended sub-diffusive regime at intermediate times before finally diffusive motion is recovered at very long times. Particle dynamics in one- and two-dimensional potentials are quantitatively compared. [1] R. D. L. Hanes, C. Dalle-Ferrier, M. Schmiedeberg, M. C. Jenkins, S. U. Egelhaaf, Colloids in one dimensional random energy landscapes, Soft Matter 8, 2714 (2012). [2] F. Evers, R. D. L. Hanes, S. U. Egelhaaf, Particle dynamics in two-dimensional potential energy landscapes, in preparation.

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Colloidal Stability of emulsions and nanoparticles in pharmaceutics Mathias Fleury Formulaction, L'Union, France

The world of drug delivery is getting every day more efficient with new product forms, which are directly targeting the deficient organs. Colloidal systems such as emulsions (simple or multiple) or nanoparticle suspensions are now widely used as drug carriers or nutritional solutions in this respect. These new product forms allow better targeting and assimilation for the patient, and give rise to new solutions for the drug designers. However, the stability of these inherently unstable colloidal systems makes them complex to formulate and study. Despite the existence of models and increasing knowledge on physical chemistry to help the formulator to tend towards more stable formulations, he cannot take the risk to select an industrial formula for its sole end-use properties without testing the stability experimentally, when an unstable formulation can risk the life of the patient he is trying to cure. Therefore, the companies developing instruments have worked in collaboration with the physical chemists, from industry and research, to develop new techniques of analysis for either predicting the stability of these mixtures, or reducing times of ageing tests. These techniques, although very powerful, require a good knowledge of measurement to interpret the results. This presentation aims to review the main examples of multiple light scattering to monitor the physical stability of colloidal systems for pharmaceutical applications.

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Many-body interactions in colloidal dispersions Jan Forsman 1; Clifford E. Woodward 2 1Lund University, Theoretical Chemistry, Lund, Sweden; 2University of New South Wales, ADFA, Canberra, Australia

We have developed a benchmark theory for many-body interactions in a colloidal particle+ideal polymer mixture. We have addressed this system from the point of view of an effective potential theory. Averaging over polymer configurations defines a many-body potential of mean force between the colloidal particles.This is an old approach that has faltered in past attempts, due to the fact that N-body potentials rapidly become unwieldy to use, beyond the level of pair interactions (N>2). Our recent breakthrough has been to develop a useful effective N-body potential between hard-sphere particles, immersed in an ideal polymer solution, which appears accurate to all-orders in N (Soft Matter 8, 2121 (2012)). Our theory utilizes a generalization of the Edwards-deGennes treatment of continuous chains. Thus, polymer configurations are appropriately accounted for (in contrast to the Asakura-Oosawa model). We are currently in the process of lifting the restriction to ideal chains. The new theory, able to treat "real" mixtures, with polymer interactions including dispersion, electrostatic, excluded volume etc., will be of great practical use for the colloidal community.

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Fluid mediated gelation and crystallization of hard spheres Andrea Fortini Universität Bayreuth, Bayreuth, Germany

A mixture of hard-sphere particles and model emulsion droplets is studied with a Brownian dynamics simulation. We find that the addition of nonwetting emulsion droplets to a suspension of pure hard spheres can lead to both gas-liquid and fluid-solid phase separations. Furthermore, we find a stable fluid of hard-sphere clusters. The stability is due to the saturation of the attraction that occurs when the surface of the droplets is completely covered with colloidal particles. At larger emulsion droplet densities a percolation transition is observed. The resulting networks of colloidal particles show dynamical and mechanical properties typical of a colloidal gel. The results of the model are in good qualitative agreement with recent experimental findings [E. Koos and N. Willenbacher, Science 331, 897 (2011)] in a mixture of colloidal particles and two immiscible fluids.

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Physical chemistry analysis of bitumen as a colloidal system Luigi Gentile 1; Luigi Filippelli 1; Baldino Noemi 2; Maria P. De Santo 3; Cesare Oliviero Rossi 1 1University of Calabria, Department of Chemistry, Rende (CS), Italy; 2University of Calabria, Engineering Modelling Department, Rende (CS), Italy; 3University of Calabria, Department of Physics, Rende (CS), Italy

Bitumen can be described as a colloidal dispersion of asphaltene particles, coated with layers of stabilizing polar resins, in a continuous oil phase. The bitumen nature is under discussion due to a very complex chemical composition and consequently physical chemistry properties. We used rheology, atomic force microscopy (AFM) and Nuclear magnetic resonance (NMR) in order to obtain a “picture” of bitumen structure. In fact AFM phase-contrast imaging in the tapping mode is a powerful method in surface characterization. On the other hand AFM can be performed at relatively low temperature. Combining rheology and NMR results we were able to follow the transitions in temperature and consequently bitumen structure change. We applied the Inverse Laplace Transform to NMR echo decay to obtain spin-spin relaxation time distributions that correspond to different macro-aggregates. We propose the used physical chemistry techniques as an alternative to the empirical standardize test to characterize the bitumen. The experimental results confirm the colloidal nature of the bitumen.

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Critical Casimir forces in colloidal suspensions: a numerical study Nicoletta Gnan Università Sapienza, Physics Department, Roma, Italy

Describing effective interactions among colloidal particles in the presence of macromolecular additives is crucial for soft matter science. An interesting case of effective interaction is the one arising when two colloids are dispersed in a critical fluid. Close to the critical point, thermal fluctuations of the order parameter are correlated over scales that are larger than the solvent size: the confinement of such fluctuations in between the two colloids give rises to long-range effective forces, named critical Casimir (CC) forces. Theoretical investigation of CC forces have provided accurate predictions for the radial dependence of the effective potential (V_eff); moreover direct experimental evidence of CC forces has been provided and their role in colloidal aggregation has been addressed. Numerical simulations of simple models can help understanding if, how and when critical fluctuations may play a role in colloidal aggregation. To this aim, in our work we evaluate numerically V_eff between two hard-sphere colloids immersed in an implicit solvent, in the presence of interacting depletant particles, for a wide region of state points including the critical region. We provide a complete evaluation of the colloid stable and unstable regions and the relative location of these regions with respect to the depletant gas-liquid critical point as a function of the depletant-colloid size ratio for two different depletant models. We discuss under which conditions critical fluctuations of the depletant can be used to effectively manipulate colloidal aggregation. Moreover we quantify V_eff when a colloid-depletant attraction is turned on and we follow the evolution from the case in which the depletant density close to the colloids changes from values smaller to values larger that the bulk thus effectively implementing the so-called (+, +) and (−, −) boundary conditions (BC) defined in field theoretical approach for the description of CC forces. We also investigate the case of (+, −) BC, where V_eff becomes repulsive. Our study provides a guidance for a for a design of the interaction potential which can be exploited to control the stability of colloids

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Effect of cationic polymers on the foam rheological properties Konstantin Golemanov 1; Nadia Politova 2; Slavka Tcholakova 2; Nikolai Denkov 2; Kavssery P. Ananthapadmanabhan 3; Alex Lips 3 1Unilever Discover R&D, Structured Materials and Process Science, Vlaardingen, Netherlands; 2University of Sofia, Department of Chemical Engineering, Sofia, Bulgaria; 3Unilever Global Research Center, Trumbull, United States

Foams which have air volume fraction above ≈74 % exhibit complex visco-elastic behaviour. The rheology of such foams is usually described well by the Herschel-Bulkley (HB) rheological model. According to the HB model, the shear stress has two components: elastic (yield stress), τ0, which does not depend on the shear rate, and viscous stress, τV, which increases monotonically with the shear rate. The foams with higher surface modulus of the bubbles, G, also have higher τV. Here we study two foaming surfactant systems, designated as A and B. System A is a mixture of anionic and zwitterionic surfactant. It forms foams which are very stable to coalescence and have low G. Adding myristic acid to A leads to much higher G and respectively – to higher viscous friction in the foam (system B). Both A and B obey the HB model. Here we study the effect of two cationic polymers (Merquat 100, Jaguar C-13S) on the properties of these systems. We measured the shear stress as a function of the shear rate. Neither τ0 nor τV in A or B was affected by the addition of Merquat. The addition of Jaguar lead to (1) Significant increase of τ0 for A; (2) Presence of a maximum and consecutive minimum in the rheological curve for system B, which is in contradiction with the HB model. This effect can be explained with the formation of polymer bridges between the neighbouring bubbles. The maximum in the total stress reflects the process of breaking of these bridges.

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Sensitive polymer-clay composite particles: stability and adsorption mechanism Anna Große ; Karl-Friedrich Arndt Technische Universität Dresden, Department of Chemistry and Food Chemistry / Chair Physical Chemistry of Polymers, Dresden, Germany

Polymers adsorb on clay surfaces. This results in composites that represent a new class of materials, and combine the properties of the individual components. The aim of this study was to produce sensitive composite particles in the nanometer scale based on poly(N-isopropylacryamide) (PNIPAAm) and clay. The particles are formed by the adsorption of polymer chains on the clay surface in aqueous solution. The adsorption mechanism was elucidated. That helped to make statements about size, shape and properties of the formed particles. The inorganic clay Laponite is a synthetic hectorite. The clay particles are anisotropic platelets of 25 nm in diameter and approx. 1 nm in thickness. In aqueous solution, they exfoliate and show a strongly negative face charge originating from the water-particle interactions. PNIPAAm is a thermosensitive polymer having a lower critical solution temperature of about 33 °C. Sensitive composite particles were obtained by mixing stock solutions of the respective components in different concentration ranges and in different mixing ratios of clay and polymer. The influence of polymer and clay concentration on the solution properties was investigated in terms of viscosity and transparency. Light scattering measurements helped to analyze the size of the formed composite particles and to confirm the adsorption of polymer on the clay surface. Adsorbed polymer chains had an influence on the zeta potential of the particles and hence on their stability. Since the particles have a negatively charged surface, the adsorption of the polymer chains shifts the zeta potential clearly to positive values. Its investigation allowed to complement the results obtained by light scattering and at the same time to support them. Finally, to examine the sensitive properties of the composite particles, the influence of temperature on the size and behavior in solution was studied.

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Effect of particle anisotropy or polydispersity on the equation of state of colloidal dispersions Joseph Diatta ; Yannick Hallez ; Martine Meireles Laboratoire de Genie Chimique, Interfaces and Dispersed Media Engineering, Toulouse, France

The equation of state of a colloidal dispersion relates the osmotic pressure to the solid volume fraction in the dispersion. For example, it is used to determine an effective diffusion coefficient for the colloids or to predict changes of state of the colloidal dispersion, with applications to many industrial processes like transport, filtration, centrifugation or coating, among others. It has been demonstrated recently that the Primitive Model combined with the Cell Model allows to perform numerical simulations without tunable parameters able to reproduce accurately equations of state for colloidal dispersions obtained experimentally with osmotic compression techniques (Jönsson et al., Langmuir, 2011). Numerical results were either based on the Poisson-Boltzmann equation or on Monte Carlo simulations and both techniques yielded very close results, thus indicating no effects of ion specificity. In the aforementioned work, colloids were silica or polystyrene spheres, and the Cell Model was based on a spherical colloid inside a spherical shell. In the present work, we extend these results by solving numerically the Poisson-Boltzmann equation in a cubical cell containing one or more colloids using a Finite Difference / Level Set approach. The osmotic pressure is computed by a mechanistic approach, i.e. by integrating the normal osmotic and Maxwell stresses on the domain boundary. The previous Cell Model results are recovered with an excellent agreement. Simulations of a large number of spherical colloids in an "extended" cubical cell also yield osmotic pressures in good agreement with previous numerical and experimental results. The numerical method is then exploited to simulate a large number of anisotropic or polydisperse colloids and the results highlight the associated changes in the shape of the equation of state. These changes are linked to the self-organisation inside the dispersion, an effect impossible to capture with the classical Cell Model. We plan to compare the radial distribution functions obtained numerically with results from SAXS experiments performed on concentrated colloidal dispersions after osmotic compression.

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Colloid titration of silica particles – Determination of specific interactions by a surface-sensitive method Mathias Hanisch ; Christian Sauerbeck ; Jochen Schmidt ; Robin N. Klupp Taylor ; Wolfgang Peukert FAU Erlangen-Nuremberg, Institute of Particle Technology, Erlangen, Germany

Silica has become an important material in colloid science and materials engineering in the last decades due to its ease of synthesis in the form of small particles and coatings. Moreover, various methods permit the functionalization of the silica surface with different chemical groups, e.g. polymer initiator compounds, making them attractive for the synthesis of organic-inorganic hybrid materials. In contrast to their ease of synthesis, the chemistry of silica particles and coatings is more complex. Therefore we are studying the surface physiscochemistry of silica particles by colloid titration, a method that permits the gathering of information directly from the surface. By subtracting a blind sample titration curve from the particle titration curve a pH dependent surface charge plot can thus be obtained. We investigate the specific adsorption of monovalent cations for porous and non-porous particles. The removal of surface silanol groups (Si-OH) by heat treatment can be investigated with this method and the pH dependent surface charge can be compared with zeta potential measurements. The ongoing work investigates the adsorption behavior of noble metal ions to the silica surface, a process which we have observed to be critical for the formation of novel anisotropic metal-metal oxide nanostructures. Furthermore, we want to extend the usage of this method to other oxide particles or particulate systems such as charged polystyrene latexes with defined surface groups. Through this we hope to show that colloid titration can contribute significantly to a better understanding of the interaction of inorganic and organic ions with colloidal surfaces.

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Concentration dependent swelling of loosely cross-linked ionic microgel dispersions in the fluid regime Peter Holmqvist 1; Priti Mohanty 2; Peter Schurtenberger 2; Gerhard Nägele 1; Marco Heinen 3 1Forschungszentrum Jülich, Jülich, Germany; 2Division of Physical Chemistry, Lund, Sweden; 3Institut für Theoretische Physik II, Düsseldorf, Germany

Dispersions of cross-linked microgel particles such as poly (N-isopropylacrylamide) (PNiPAm) have become popular model systems of soft colloids. The PNiPAm particles swell reversibly when the dispersion is cooled from the collapsed state to lower temperatures, T. We have found that in addition to the effect of pH and T on the swelling of the microgel particles the concentration, number density np, of charge microgel particles can strongly affect the size of the microgels in their swollen state. We report an experimental-theoretical study of the T- and np dependent swelling behavior of weakly cross-linked PNiPAm ionic microgel particles in the deionized fluid phase. While the collapsed state shows no dependence on the microgel number density, np, the swelling at lower T is more pronounced at lower concentrations. The static pair correlations and short-time diffusion functions, and the np - and T dependence of the microgel radius, Rtot, and effective charge, Z, are studied using static and dynamic light scattering (SLS/DLS) in combination with state-of-the-art analytical theoretical schemes based on a Yukawa-type effective pair potential and a core-shell model. We show that only such a combined, simultaneous fit of static and dynamic scattering functions allows for an unambiguous determination of Rtot and Z. An important implication on this finding is that the determined size of the microgels from the dilute state might not be valid at higher concentrations. A common approach to determine the volume fraction, φ, is to extract Rtot as a function of T in the dilute regime of non-interacting particles from measuring the form factor, P(q), single-particle diffusion coefficient or intrinsic viscosity, and to calculate φ at low as well as at high values of np from this “known” size. This approach can affect the interpretation of experimental data in relation to theory and simulation since the volume fraction can be wrong due to the unknown size of the particles.

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pH-triggered polyelectrolyte desorption from electrostatically surface modified poly(lactic-co-glycolic acid) nanoparticles Manuel Häuser 1; Monika Schönhoff 1; Klaus Langer 2 1University of Muenster, Institute of Physical Chemistry, Münster, Germany; 2University of Muenster, Institute of Pharmaceutical Technology and Biopharmacy, Münster, Germany

Nanoparticles prepared of poly(lactic-co-glycolic acid) (PLGA) represent a promising biodegradable drug delivery system. Particles of an appropriate size can be assembled via an emulsion diffusion method, using polyvinyl alcohol as a stabilizing agent [1]. The surface of the obtained particles can be electrostatically modified by adsorbing different polyelectrolytes using the layer-by-layer self assembly technique [2]. By choosing weak polyelectrolytes, such as polyacrylic acid (PAA), it is possible to generate a particle system, which changes the amount charges on the surface upon variation of the pH of the environment, due to a variable state of deprotonation of the PAA. The aim of this work is to generate PLGA nanoparticles with a pH-tunable polymeric shell consisting of PAA. Further adsorption of cationic polymers, such as polydiallyldimethylammonium chloride (PDADMAC), leads to a nanoparticle system which is capable of releasing adsorbed polymer upon pH decrease due to reduced electrostatic attraction between PAA and PDADMAC. In this work, the described release processes have been quantitatively investigated. Successful nanoparticle assembly was monitored via dynamic light scattering (DLS) and zeta potential measurements, whereas the quantification of desorbed polymer was carried out using NMR techniques. The amount of released PDADMAC clearly depends on the pH of the environment and thus on the state of deprotonation of the pH-sensitive PAA layer. Correlation of obtained data is found to be in good agreement with the state of ionization of PAA in polyelectrolyte multilayers, as described in literature. References: [1] Astete, C.; Sabliov, C. J. Biomater. Sci. Polymer Edn., 17, 247 (2006) [2] Decher, G.; Hong, J.; Schmidt, J. Thin Solid Films, 210, 831 (1992)

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Stabilization of polymer colloid dispersions with pH-sensitive poly(acrylic acid) brushes Baptiste Jaquet 1; Dan Wei 2; Bernd Reck 3; Hua Wu 1; Massimo Morbidelli 1 1Eidgenössische Technische Hochschule Zürich, Departement of Chemistry and applied biosciences, Zurich, Switzerland; 2South China University of Technology, School of Chemistry and Chemical engineering, Guangzhou, China; 3BASF SE, Ludwigshafen, Germany

Polyelectrolyte brushes are widely used for surface modification of nano- and colloidal particles because of their ability to dramatically change their conformation, hydrophobicity, polarity, charge, etc., as a response to smooth variations in environmental conditions. In this work, we have studied the stability behavior of polymer colloids with grafted poly-acrylic acid (PAA) surface brushes. We have measured experimentally the Fuchs stability ratio (W) as a function of electrolyte concentrations at different pH for three different latices containing varying amount of acrylic acid. An extensive study of the polyelectrolyte conformation as a function of the pH and electrolyte has been performed using dynamic and static light scattering, is consistent with previous literature theoretical work on polyelectrolyte brushes. We show the expected transition between different brush conformation regimes by addition of salt, at different pH. This study gives insight into the interplay of electrostatic and steric interactions stabilizing the polymer particles. In particular, it is observed that at pH<3, the PAA brushes are in a collapsed state and their contribution to the colloidal stability is insignificant. At the intermediate pH~5, the PAA brushes are partially stretched, and their contribution to the colloidal stability is substantial and increases as the length of the PAA brushes increases. Under alkaline conditions (pH>8), where the brushes are in the salted brush regime, the colloidal stability is much higher than that at pH~5, and becomes independent of the PAA content, i.e., 1% or 2%. This experimental result support the widely-used local electroneutrality approximation within the polyelectrolyte brushes in these conditions. A model for the evaluation of interparticle potential is presented.

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Characterization of gel formulations used for paint stripping Malgorzata Jaworska ; Otmar Vogt Cracow Univeristy of Technology, Institute of Organic Chemistry and Technology, Cracow, Poland

Thickeners and gelling agents are widely used in various industries because of its qualities. Properties of these substances (due to its chemical structure), must guarantee obtaining the products of the assumed consistency and stability. Among others products the removing paint formulation should show these kind of properties. The selection of suitable emulsifying and thickening agents, which can keep all the ingredients in the proper form which allows easy application of such a kind of gels requires optimization for a particular formulation. Different types of gelling agents, natural and synthetic, are applied to obtain such mixtures [1-2]. Commercially available products are based on methylene chloride, which is unsafe to the environment. The aim of this study was obtaining methylene chloride-free gel formulations and compare their structures with commercial products. Based on our own formulation, the mixtures containing as a gelling agents D-DBS and MHCP were prepared. Brookfield Rheomether Model R/S Plus and Medingen Rheometer RN 4.1 was appied to rheological studies of the systems. Measurements were carried out isothermally, at 250C temperature. Gel strength was also investigated by oscillatory measurements. The gels morphology were analyzed using an optical microscope with polarized cap (microscope series B1-220) and using the transmission electron microscopy (TEM). For the studied systems the viscosity curves and flow curves were drawn. Also and elastic shear modulus (G ') and viscous modulus (G ") were determined. The obtained results showed that prepared gels are non-Newtonian liquids with pseudoplastic rheological behaviour. References: 1. W. Fabianowski, Journal of the Polish Society of Cosmetic Chemists, 2001, 3/4 (4), 42-53 2. Tomaszkiewicz-Potêpa, E. Sikora, D. Heród, Chemik science-technique-market, 2005, 58(1), 11-15

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Enhanced electrolytic dissociation in low-dielectric-constant systems Marek Kosmulski ; Edward Maczka Lublin University of Technology, Lublin, Poland

The conductance of solutions of weak acids (0- 0.02 M) in aqueous dioxane and of dispersions of alumina and titania in such solutions was studied. The ceramic oxides enhanced the electric conductance of solutions of oxalic, benzoic and salicylic acid, but not of sulfuric acid. The enhanced conductance is due to surface-induced electrolytic dissociation, that is, to adsorption of anions accompanied by the salvation of protons in solution. This phenomenon was observed at a dielectric constant as low as 4.4 A semi-quantitative model of the speciation in dispersions was proposed.

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Breakup dynamics of colloidal clusters in shear flows Yogesh M. Harshe 1; Marco Lattuada 2 1ETH Zurich, Institute for Chemical and Bioengineering, Zurich, Switzerland; 2University of Fribourg, Adolphe Merkle Institute, Marly, Switzerland

In this work, we present a broad spectrum computational study of the breakage dynamics of colloidal clusters in the presence of shear flow. We have formulated a model, which uses Stokesian dynamics to estimate the hydrodynamic interactions among the particles in a cluster, DLVO theory to describe the normal interparticle interactions, and tangential interactions through discrete element method to account for contact forces. Fractal clusters composed of monodisperse spherical particles were generated using different Monte Carlo methods, covering a wide range of cluster masses and fractal dimensions. The study is divided in to two parts, one related to first breakage events in colloidal clusters exposed to shear forces, while the second part focuses on their long term dynamics. The time required to reach the first breakage event of a cluster was used to compute a characteristic breakage rate constant for various flow magnitudes under simple shear conditions. The breakage rate constant showed a power law dependence on the product of the aggregate size and the applied stress, with values of the corresponding exponents depending only on the aggregate fractal dimension and the type of flow field, whereas the prefactor of the power law relation also depends on the size of the primary particles comprising a cluster. The long-term dynamics was quantified by monitoring the evolution of the average clusters size, fractal dimension, average particle coordination number and number of fragments. When the time was rescaled by the characteristic time for the first breakage event, the dynamics all clusters, independent of mass and fractal dimension, showed a universal behavior. The results of these simulations provide new insights on the complex interplay between cluster morphology and hydrodynamic and interparticles interactions in sheared dispersions of clusters. References: Harshe Y.M. and Lattuada M., Langmuir 2012, 28, 283–292 Harshe Y.M. and Lattuada M., Soft Matter, submitted

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Self-consistent field predictions for quenched spherical biocompatible triblock copolymer micelles Jérôme G.J.L. Lebouille 1; Remco Tuinier 1; Leo F.W. Vleugels 1; Martien A. Cohen Stuart 2; Frans A.M. Leermakers 2 1DSM BV, Advanced Chemical Engineering Solutions, Geleen, Netherlands; 2Wageningen University, Laboratory for Physical Chemistry and Colloid Science, Wageningen, Netherlands

We have used the Scheutjens-Fleer self-consistent field (SF-SCF) method to predict the self-assembly of triblock copolymers with a solvophilic middle block and sufficiently long solvophobic outer blocks. We model copolymers consisting of polyethylene oxide (PEO) as solvophilic block and poly(lactic-co-glycolic) acid (PLGA) or poly(ε-caprolactone) (PCL) as solvophobic block. These copolymers form structurally quenched spherical micelles provided the solvophilic block is long enough. Predictions are calibrated on experimental data for micelles composed of PCL-PEO-PCL and PLGA-PEO-PLGA triblock copolymers prepared via the nanoprecipitation method. We establish effective interaction parameters that enable us to predict various micelle properties such as the hydrodynamic size, the aggregation number and the loading capacity of the micelles for hydrophobic species that are consistent with experimental finding.

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Controlled nanoparticle formation by diffusion limited coalescence J.G.J.L. Lebouille 1; R. Stepanyan 2; J.J.M. Slot 3; R. Tuinier 4; M.A. Cohen Stuart 5 1DSM BV, Advanced Chemical Engineering Solutions, Geleen, Netherlands; 2DSM BV, DSM Research, Geleen, Netherlands; 3Eindhoven University of Technology, Department of Mathematics and Computer Science, Eindhoven, Netherlands; 4Utrecht University, Van 't Hoff Laboratory, Debye Institute, Utrecht, Netherlands; 5Wageningen University, Laboratory for Physical Chemistry and Colloid Science, Wageningen, Netherlands

Polymeric nanoparticles (NPs) have a great application potential in science and technology. Their functionality strongly depends on their size. We present a theory for the size of NPs formed by precipitation of polymers into a bad solvent in the presence of a stabilizing surfactant. The analytical theory is based upon diffusion-limited coalescence kinetics of the polymers. Two relevant time scales, a mixing and a coalescence time, are identified and their ratio is shown to determine the final NP diameter. The size is found to scale in a universal manner and is predominantly sensitive to the mixing time and the polymer concentration if the surfactant concentration is sufficiently high. The model predictions are in good agreement with experimental data. Hence the theory provides a solid framework for tailoring nanoparticles with a priori determined size.

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Synthesis of Janus particles using micromolding technique Chang-Hyung Choi 1; Sung-Min Kang 1; Chang-Soo Lee 1; Young-A Son 2 1Chungnam National University, Chemical Engineering, Daejeon, Republic of Korea; 2Chungnam National University, Department of Advanced Organic Materials and Textile System Engineering, Daejeon, Republic of Korea

The physical and chemical properties of polymeric particles are important for their use in microrheology, functional materials and self-assembly. We report the simple approach for the synthesis of Janus particles having amphiphilic property using micromolding technique. The Janus microparticles including segregated hydrophilic and hydrophobic sections are synthesized by combination of micromolding technique and photopolymerization. We can freely control the shape, size, and functionality of Janus particles. In addition, the Janus particles show high monodispersity, which is essential advantage in control of properties. Finally, we investigate the feasibility of self-assembly of amphiphilic Janus particles at water-oil interface. We trust that this approach for the synthesis of novel functional materials is useful and the Janus particles could be applied to study fundamental colloidal interactions at micron scale.

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Adsorption versus aggregation. Particles and surface of same material Per Linse ; Hakan Wennerstrom Lund University, Physical Chemistry, Department of Chemistry, Lund, Sweden

A model for the adsorption of colloidal particles on a planar surface is analyzed by using a thermodynamic chemical equilibrium model and Monte Carlo simulations. Central to this investigation are that (i) particles and surface are considered to be of the same material, and (ii) the particle–surface and particle–particle interactions are related using the Derjaguin approximation using a surface–surface square-well potential as a basis. Thereby, all interactions within the system are characterized by the same parameters, and hence the difference between particle adsorption on the surface and particle aggregation in bulk is solely due to geometrical effects. Equilibrium constants for the different binary associations are calculated from the interaction potentials enabling a direct comparison between predictions based on a chemical equilibrium model and on computer simulations with no adjustable parameters. Our study is relevant both for understanding processes where colloidal particle adsorption is used to modify surface properties and also for the understanding of heterogeneous versus homogeneous nucleation.

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Coalescence of Metallic Nanoparticles at Room Temperature and Application in Printed Electronics Michael Grouchko ; Shlomo Magdassi The Hebrew University of Jerusalem, Chemistry, Jerusalem, Israel

Metallic particles are considered hard materials, which are characterized by a high melting point (around 1000°C) and large Young’s modulus (~100 GPa). Therefore, coalescence and sintering of metallic particles usually take place only under high pressure and temperature. Fabrication of electric circuits on heat-sensitive substrates such as paper, plastic packages, and various polymeric substrates has attracted significant interest as a pathway to achieve flexible printed electronic devices. A major step in the fabrication process is the sintering of the printed metallic particles, which is conventionally carried by heating to temperatures higher than 200°C. However, due to the sensitivity of most plastic substrates to high temperatures, such heat treatment is not suitable, and therefore there is a need to cause metallic particles to coalesce at low temperatures. He we will describe how we can utilize colloid chemistry tools for triggering coalescence and sintering of silver nanoparticles that takes place on solid substrates even at room temperature. The approach is based on causing close packing of the particles while desorbing the dispersing agent from the nanoparticles surface. We will demonstrate how the sintering process yields printed patterns that possess high electrical conductivity, and the application of the nanoparticles in optoelectronic devices.

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Acid coagulation of natural rubber latex Paul Menut 1; Yacine Hemar 2; Frederic Bonfils 1; Christian Sanchez 1 1UMR IATE (CIRAD, UM2, INRA, Montpellier SupAgro), Montpellier, France; 2University of Auckland, Auckland, New Zealand

Natural rubber latex is extracted from Hevea trees. It is a complex colloidal suspension of poly-isoprene particles stabilized by a protein/phospholipidic negatively charged membrane. Upon acidification, the aggregation is initiated, and particles assemble in a percolating network or colloidal gel. This is the first step of a process which gives rise to the production of natural rubber, a material widely used in the world, with unique and challenging properties yet not clearly understood from a scientific perspective. In this study we focus on the early mechanism of particles aggregation, which should play a key role in the control of the natural rubber matrix properties. Local effects were inhibited by the use of Glucono-delta-Lactone (GDL), which hydrolysis initiates a progressive and homogeneous acidification of the suspension. Natural rubber latex is an opaque solution, which strongly diffuse light. Static or Dynamic Light Scattering, which are conventional technics used to follow the aggregation of particles in solution, cannot be used directly due to a strong multiple scattering. We skipped the problem by using ganulo-polarimetry, which allows direct and independent measurements of particles sizes and volume fraction in a turbid media. To do so, we characterized for the first time the transport of incoherent polarized light in natural rubber latex. The following analysis of the Mueller matrices allows particles sizing, even at high volume fraction. This allows the precise determination of the agglomerate size growth with time. We combine rheological measurements and confocal microscopy to characterize the structure formation of the product. In order to get a clear description of the gelification behavior of those unique natural products, a large range of particles volume fraction and acidification kinetics were investigated. The results showed a typical colloidal gel behavior, where the structure of the strands can be control by the modulation of the particles attraction forces. This might allow new ways to induce natural rubber latex coagulation, in order to reach a better quality of the product.

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Interactions and self-assembly of soft magneto-responsive anisotropic colloids Adriana M. Mihut 1; Jérôme J. Crassous 1; Hervé Dietsch 2; Peter Schurtenberger 1 1Lund University, Physical Chemistry 1, Lund, Sweden; 2Fribourg University, Adolphe Merkle Institute, Fribourg, Switzerland

We use an advanced suite of magnetic model colloidal particles to single out the action of various contributions to the potential in a highly controlled way. We further explore the influence of directed interactions on suspension properties and self-assembly. The overall aim is to create links to biological self-assembly processes and develop design rules for the fabrication of well-defined nanostructures with tailored properties through controlled self-assembly. The magnetic particles consist on new highly anisotropic spindle shape maghemite coated with silica, which have the ability to align parallel to the magnetic field. These particles have been encapsulated either in a polystyrene latex stabilized by a thin PNIPAM shell or in a thermosensitive PNIPMAM microgels in order to achieve electrosterically stabilized particles with different softness. These particles have been investigated from the dilute to the concentrated regime at various temperatures by using small-angle X-ray scattering in the presence of a homogeneous magnetic field, and the structural properties are compared to the magnetic properties of the suspensions determined by magnetometry.

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Fractionation of Complex Industrial Colloidal Systems Jules Mikhael ; Volodymyr Boyko ; Wendel Wohlleben BASF SE, Material Physics, Ludwigshafen, Germany

A huge variety of products containing submicron particles are nowadays produced in industrial processes all around the world. Such colloidal particles are typically used in products to help bind, stabilize, coagulate, suspend, thicken, and form films. The physical properties of such nanoparticles can therefore to a large extend define the end property of the product. Here we demonstrate that investigating complex colloidal systems by means of analytical ultracentrifugation can deliver valuable information not accessible by common techniques.

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Dipolar ionic microgels Priti Mohanty 1; Anand Yethiraj 2; Peter Peter Schurtenberger 1 1Lund University, Division of Physical Chemistry, Lund, Sweden; 2Memorial University, Department of Physics and Physical Oceanography, Newfoundland Labrador, Canada

Ionic microgels1,2 are a class of soft colloids with an effective pair potential that crosses over from a screened Coulomb (or Yukawa) type interaction at large distances to a much softer repulsive interaction at short distances3,4. Here we report the effect of adding an anisotropic dipolar contribution to ionic microgels with such "ultra-soft" interactions. We use an alternating electric field to induce a tunable dipolar contribution, and study the resulting particle self-assembly and phase transitions in-situ with confocal laser scanning microscopy. We find significant field-induced structural transitions at low as well as at very high effective volume fractions φeff. At φeff = 0.1, we observe a transition from an isotropic to a string fluid. At φeff = 0.85, there is a reversible re-entrant disorder-order transition, featuring a transition from a glass to a dipolar ordered structure, followed by the onset of a gas - (string) solid coexistence. At φeff = 2.0, i.e. far above close packing, evidence for a field-induced arrested phase separation is found. These experimental results are discussed in the light of previously studied field-induced phase behaviour of dipolar hard and charged colloids5. 1) U. Gasser, B. Sierra-Martin, and A. Fernandez-Nieves, Phys. Rev. E 79,051403(2009). 2) P. S. Mohanty and W. Richtering, J. Phys. Chem. B 112, 14692(2008). 3) D. Gottwald, C. N. Likos, G. Kahl, and H. Löwen, Phys. Rev. Lett. 92,068301(2004). 4) D. Gottwald, C. N. Likos, G. Kahl, and H. Löwen, J. Chem. Phys. 122,074903(2005). 5) A. Yethiraj and A. van Blaaderen, Nature 421, 513 (2003).

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Colloidal metallic nanoparticles as surface-enhanced raman Spectroscopy substrates for forensic analysis of questioned documents André Braz 1; María López-López 1; Carmen García Ruiz 1; Gemma Montalvo 2 1University Institute of Research in Police Sciences and University of Alcalá, Analytical Chemistry, Alcalá de Henares, Spain; 2University Institute of Research in Police Sciences and University of Alcalá, Physical Chemistry, Alcalá de Henares, Spain

Forensic examinations of documents usually involve physical and chemical analysis of inks to prove alteration and forgery. Raman Spectroscopy (RS) is a very attractive technique for ink analysis because it is chemically selective and preserves the integrity of the evidence. However, its main drawbacks are low sensitivity and susceptibility to fluorescence, usually from impurities or the sample itself. Both limitations may be overcome by using Surface-Enhanced Raman Spectroscopy (SERS), which consists of treating samples with a nanostructured metallic surface or colloid, usually silver (Ag) or gold (Au). Colloids’ potential in forensic science and, in particular, for the study of questioned documents has been little explored and refers to ballpen [1-3] and inkjet inks [4, 5]. This research expands the existing publications by applying SERS to the discrimination of blue and black inks originated by different inkjet and laser printers. Silver colloidal nanoparticles obtained by reduction of silver nitrate with sodium citrate [6] were used due to preliminary results by RS showing weak signals or fluorescence for almost all printing inks. Interestingly, spectra obtained by SERS were many orders of magnitude more intense than by RS and fluorescence was entirely removed. SERS allowed for the discrimination of many brands of printers, especially successful with laser printers, solely based on Raman signature spectra. [1] Seifar RM, Verheul JM, Ariese F, Brinkman UATh, Gooijer C. Analyst 2001;126(8):1418-22 [2] White PC, Sci. Justice 2003; 43(3):149-52. [3] Geiman I, Leona M, Lombardi JR, J. Forensic Sci. 2009; 54(4):947-52. [4] Littleford RE, Hughes MP, Dent G, Tackley D, Smith WE, Appl. Spectrosc. 2003; 57(8):977-83. [5] Rodger C, Dent G, Watkinson J, Smith WE, Appl. Spectrosc. 2000; 54(11):1567-76. [6] Lee, P. C.; Meisel, D, J. Phys. Chem. 1982, 86, 3391.

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Streaming potential studies of hematite nanoparticle monolayers on mica Maria Morga ; Zbigniew Adamczyk ; Magdalena Oæwieja Polish Academy of Sciences, Jerzy Haber Institute of Catalysis and Surface Chemistry, Cracow, Poland

Electrokinetic properties of α–Fe2O3 (hematite) nanoparticle monolayers on mica were thoroughly characterized using the streaming potential method. Hematite suspensions were obtained by acidic hydrolysis of ferric chloride. The average size of particles (hydrodynamic diameter ), determined by dynamic light scattering (DLS) and AFM, was 22 nm (pH= 5.5, I = 10-2 M). The suspension was stable within a long period of time reaching 15 days, and in the range of pH varied between 10-4M – 10-2M NaCl. The dependence of the mobility and the zeta potential of the particles on ionic strength and pH was also investigated. The zeta potential of the hematite particles was positive for pH lower than 8.9 ( isoelectric point) and negative otherwise. The hematite monolayers on mica were produced under diffusion-controlled transport from the suspensions of various bulk concentration. The monolayer coverage, quantitatively determined by AFM and SEM, was regulated within broad limits by adjusting the nanoparticle deposition time. The zeta potential of hematite monolayers was investigated in terms of the particle coverage using streaming potential method. The dependencies obtained this way for various pH values were successfully interpreted in terms of three-dimensional electrokinetic model. On the basis of experiments, a universal calibrating graph was produced this way enabling one to determine hematite monolayer coverage from the measured value of the streaming potential. The influence of the ionic strength, varied between 10-4 and 10-2 M, on the zeta potential of hematite monolayers was also studied. Additionally, the stability of hematite monolayers (desorption kinetics) was determined under in situ conditions using the streaming potential method. Our experimental data prove that it is feasible to produce uniform and stable hematite particle monolayers of well-controlled coverage. Such monolayers may find practical applications as universal substrates for protein immobilization (biosensors) and in electrocatalytic applications. Acknowledgments: This work was supported by the Polish Ministry of Science and Higher Education (MNiSzW) and grant: POIG.01.01.02 -12-028/09.

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Open colloidal structures by hydrophobization of silica aqueous suspensions Solenn Moro 1; Bernard Cabane 2; Nicolas Sanson 1; Jean-Baptiste D'Espinose de LaCaillerie 1 1PPMD - SIMM - UMR 7615, Paris, France; 2PMMH, CNRS UMR 7636, Paris, France

The aggregation of colloidal suspensions has been widely studied over the last decade for fundamental as well as industrial purposes. The structure of the aggregates depends on various parameters such as surface adsorption (polymers, surfactants), physicochemical parameters (pH, ionic strength, temperature…) or applied stress. In our case, we studied the grafting of hydrophobic alkyl chains on silica nanoparticles in a pure aqueous medium as a way to induce aggregation. The principal aim was to control the aggregates’ density through the grafting ratio in order to obtain open structures. The grafting reaction has been performed with multi-functional silanes possessing different alkyl chain lengths. The hydrophobization reaction is here accomplished in a pure aqueous medium with a good efficiency by controlling the grafter’s introduction rate. The variation of the relative molar amount of hydrophobic precursor with respect to the reactive surface silanol groups allows achieving a controlled and progressive hydrophobicity. TGA measurements (Thermogravimetric analysis), contact angle on dip-coated films and the determination of the water adsorption’s rate at 80% relative humidity were performed on those modified silicas to characterize their hydrophobicity. The surface hydrophobization induces an aggregation whose structure depends on the grafting ratio. Cryo-TEM images reveal that initially isolated particles first turn into necklace of particles then aggregate into open three-dimensional structures with the increase of the grafting ratio. Such low dimension objects result from the balance between short range attractive hydrophobic interactions and long range repulsive electrostatic forces at basic pH which prevents the silica nanoparticles from compacting. The aggregates’ shape in suspension indicates that we can prevent the close packing of the silicas. The influence of pH, ionic strength and adsorption of polymers (poly(methacrylic acid) grafted with poly(ethylene oxide) or octyl chains) has also been studied to agglomerate the pre-formed aggregates.

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Controlled desorption of silver nanoparticles from the heterogeneous surfaces Magdalena Oæwieja ; Zbigniew Adamczyk ; Maria Morga Polish Academy of Sciences, Jerzy Haber Institute of Catalysis and Surface Chemistry, Cracow, Poland

The aim of our work was to develop an efficient method of preparation of high density silver nanoparticle films via a controlled self-assembly from aqueous nanoparticles suspensions, on polyelectrolyte supporting layers. The adsorption kinetics of silver nanoparticles on mica covered by poly(ethylene imine) (PEI), poly(allylamine hydrochloride) (PAH) or poly(dimethyl diallylamide) (PDDA) sublayers was studied. The zeta potential of mica modified by the adsorption of cationic polyelectrolytes was determined using the streaming potential measurements. The deposition of silver nanoparticles was carried out under diffusion-controlled transport from suspensions with different bulk concentrations, at pH=5.5 and various ionic strengths, varying between 10-4 and 3x10-2M. The dependence of the maximum coverage on the ionic strength and the experimental kinetic runs were quantitatively interpreted in terms of the RSA model using the effective hard particle concept. For long adsorption times, the saturation coverage was attained, increasing systematically with the ionic strength, therefore the density and structure of silver monolayers can be regulated via the ionic strength variations. The stability of silver films was determined in desorption experiments carried out for various ionic strength and temperatures. The decrease in the surface coverage of particles as a function of time was measured, which allowed one to determine the equilibrium adsorption constant Ka. The binding energy of silver particles (energy minimum depth) derived from these measurements varied between -16.9kT for I=10-1M and -18.8kT for I=10-4M, which suggests that it is mainly controlled by electrostatic interactions. This was confirmed by the investigations of silver nanoparticles desorption at various temperatures. Our studies indicate that there is a possibility of a controlled release of silver nanoparticles from films formed at solid substrates, which can be significant for biological application, e.g., in respect to antibacterial activity. Acknowledgments: This work was supported by grant: Human Capital Operation Program, Polish Project No. POKL.04.0101-00-434/08-00.

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Depletion interaction in mixed thermoresponsive microgel systems Marc Obiols-Rabasa ; Peter Schurtenberger Lund University, Physical Chemistry, Lund, Sweden

Polymer microgel particles are colloids with a cross-linked network structure, which undergo solvation changes in response to the application of an external stimulus such as temperature, electrolyte concentration or pH. The size of microgels , and thus their volume fraction, as well as the interparticle interactions can therefore be tuned in-situ [1,2]. Their capability to swell and de-swell makes microgels very attractive in a wide range of applications (i.e. as drug delivery systems). In the present work we report on the influence of depletion interactions [3] in a microgel system poly(N-isopropylacrylamide) (PNIPAM). This system consists of a dispersion of large microgel particles, which act as the colloid, in the presence of different amounts of the same microgel particles but with much smaller size (Rdepletant/Rcolloid < 0.12), which act as depletant. This induces thereby a short range attraction which is set by the low and constant depletant to colloid size ratio. Thus we look at the structural and dynamic properties of the system as a function of the strength of the interaction and the volume fraction of the particles, which represents a considerable experimental challenge. For this purpose, we use a combination of state-of-the-art direct and reciprocal space techniques such as 3D cross-correlation light scattering, small-angle X-ray (SAXS) and neutron scattering (SANS) and confocal laser scanning microscopy (CLSM), which will allows to a complete characterization at a wide range of lengths scales. [1] B. R. Saunders, B. Vincent, Adv. Colloid Interf. Sci., 80, 1 (1999) [2] M. Cloitre, in “Microgel based Materials”, H.Wyss, A.Fernandez de las Nieves, J.Mattson and D.A.Weitz Eds; Wiley-VCH, 2010; R.Bonnecaze and M.Cloitre, Adv. Polym. Sci, 236,117 (2010) [3] R. Tuinier, J. Rieger, C.G. de Kuif, Adv. Colloid Interf. Sci., 103, 1 (2003)

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Flocculation of TiO2 by hybrid polymer-inorganic nanosystems Yuriy Galyametdinov ; Regina Faizova ; Victoria Proskurina KNRTU, Kazan, Russian Federation

In recent years one of the promising directions in the science of polymers is creation of the novel types of functional materials, which are called hybrid systems. It can be used in the treatment of industrial wastewater from dispersed impurities (the processes of flocculation, filtration and flotation). In this report, on the example of model disperse systems – TiO2 suspensions the basic laws of flocculation behavior of polymer-inorganic hybrid nanosystems were systematized. In the restrained of sedimentation (Cd.f. = 8%) kinetics of flocculation of the suspension of titanium dioxide (anatase) has been studied. The hybrid flocculant dosed introduced of in water-salt environment created by NaCl and K4[Fe(CN)6] electrolytes. The synthesis of hybrid polymer-inorganic nanosystems were carried out at T = 70 °C, the initial components are: AlCl3, and (NH4)2CO3. At the quantitative level, the influence of the nature and concentration of the polymer hybrid model on the sedimentation stability of titanium dioxide suspensions in media with an ionic strength of 0,006 N to 0,1 N were analyzed. The data of optical microscopy in the presence of hybrid flocculants showed an increase of more than 40% of the average particle size of the dispersed phase (anatase) and polydispersity in size. By dynamic light scattering dimensions of the structural units and the coefficient of polydispersity in nanozole Al(OH)3 and in the systems of Al(OH)3 + anionic and cationic flocculants were determined. The efficiency of the combined action of surfactants, the hybrid flocculant and pH on the aggregative, and as a consequence, the sedimentation stability and electrosurface properties of aqueous suspensions of TiO2 were estimated. The pH of the medium affects on the adsorption of surfactant and polymer hybrid, as well as on the parameters of the electric double layer around the particles and on the macromolecules conformation at the sedimentation of the polymer hybrid particles TiO2 were found.

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Theoretical-experimental evaluation of the flocculation rate of nanoemulsions from turbidity measurements Kareem Rahn-Chique 1; Antonio M. Puertas 2; Manuel S. Romero-Cano 2; Clara Rojas 1; German Urbina-Villalba 1 1IVIC, CEIF, Caracas, Venezuela; 2Universidad de Almería, Departamento de Física Aplicada, Almería, Spain

The stability ratio of a suspension is commonly evaluated from the initial slope of the absorbance as a function of time under diffusive and reactive conditions. Puertas and de las Nieves developed a theoretical approach that allows the determination of the flocculation rate from the variation of the turbidity of a sample as a function of time [Puertas, A.M., de las Nieves, F.J. J Phys: Condens Matter 1997; 9: 3313-3320]. Here, suitable modifications of the experimental procedure and the referred theoretical approach are implemented in order to calculate the values of the stability ratio and the flocculation rate corresponding to a dodecane-in-water nanoemulsion stabilized with sodium dodecyl sulfate. The agreement between theory and experiment is good, providing a method of appraisal of the flocculation rate in emulsions.

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Nano-emulsifications through surfactant hydration : the PIT and PIC methods revisited Kevin Roger 1; Bernard Cabane 1; Ulf Olsson 2 1ESPCI, PMMH, Paris, France; 2Lund university, Physical Chemistry, Lund, Sweden

Bottom-up routes are now accepted as the most efficient way to produce nano-materials. However, both design and control of the systems and processes remain an important challenge. Indeed the wide-spread conception that these methods involve pathways far from equilibrium makes it difficult to link the macroscopic behavior with the microscopic structures. Outstanding examples of these short-comings are the emulsification methods that involve rapid changes of the surfactant layer amphiphilicity, through hydration of the surfactant head. The Phase Inversion Temperature (PIT) and Phase Inversion Composition (PIC) methods are already wide-spread in the industry but further developments require to understand precisely their mechanisms. The main claim is that a fine emulsification takes place through phase inversion because of low-interfacial tensions in its vicinity. We have investigated these methods with both model and technical systems and radically challenge this claim. We demonstrate that the non-equilibrium pathways are closely linked to the equilibrium phase behaviors and microstructures through particular states we observe at a given composition line : the Clearing Boundary. These states are not related to phase inversion and we show that phase inversion is not required to achieve nano-emulsification. We control the emulsification outcome solely by controlling the microstructure of the CB state. For example in the sub-PIT method the CB state is a superswollen microemulsion produced under gentle shear and subsequently quenched through cooling, whereas in the sup-PIC method the CN state is a bicontinuous sponge phase which decomposes into small oil droplets upon dilution. Our conclusions open a systemic way to design triggers and systems for a given nano-emulsification outcome and gather general knowledge on such useful methods.

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Why are hydrophobic/water interfaces negatively charged? Kevin Roger ; Bernard Cabane ESPCI, PMMH, Paris, France

The stability of emulsions is usually controlled with the use of amphiphilic molecules, macromolecules, or else particles that bind to the interfaces and prevent their recombination. The mechanisms by which metastability is achieved are well understood. However emulsions made of pure oil in pure water have also been found to be metastable in the absence of any added stabilizer. The droplets of these surfactant-free emulsions are negatively charged and the surface charge density increases in a typical fashion with pH. The most frequent explanation given for this phenomenon is that hydroxide ions adsorb at hydrophobic-water interfaces. However, this interpretation raises a number of difficulties, as it requires adsorption energies for hydroxide ions above 20 times the thermal energy kT and an outstanding selectivity for the hydroxide ions, compared to other anions that do not bind at such interfaces. We solve that problem by challenging the experimental feasibility of pure water/hydrophobic interfaces. We use a solvent-shifting method to produce fine emulsions with large surface areas and droplet sizes that can be easily controlled according to the amount of stabilizer. We show that the oils, even at a purity of 99% and 99.8%, contain weak acids. We demonstrate that the resulting surface charge density decreases with increasing oil purity, at a constant hydroxide ions concentration. We observe that the deliberate contamination of high purity oils with fatty acids reproduces the behaviour of lower purity oils. The pH-dependence of the surface charge density quantitatively corresponds to the titration curve of fatty acids at an interface. We conclude that hydrophobic interfaces with water are charged through the acid-base reaction of hydroxide ions with traces of fatty acids, with a reaction free energy around 20kT. This conclusion offers new opportunities to tune bottom-up routes for making nanomaterials through self-assembly, such as solvent-shifting methods.

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On the viscosity-modifying method for generating the Brownian motion of dispersed particles in a magnetic suspension Akira Satoh Akita Prefectural University, Faculty of System Science and Technology, Yuri-Honjo, Japan

In order to sophisticate the activating method of the particle Brownian motion based on fluctuation hydrodynamics. we have here presented the viscosity-modifying method and have investigated its feasibility as a simulation technique for a suspension composed of magnetic particles. In the present study, we have addressed a three-dimensional magnetic suspension in thermodynamic equilibrium to clarify the influences of various factors such as the roughness of a lattice system and the volumetric fraction of magnetic particles on the scaling coefficient of viscosity. The validity of the present results have been clarified by comparing with those of the Monte Carlo method. From comparing with the Monte Carlo results concerning the snapshots of aggregation and the pair correlation function, it is seen that the viscosity-modifying method shows good agreement with the results of Monte Carlo method in both quantitative and qualitative aspects. The scaling coefficient of viscosity is almost constant and independent of the strengths of magnetic particle-field (ξ) and particle-particle interactions (λ). Moreover, it is also almost constant for the variation in the volumetric fraction of magnetic particles. We may conclude from these results that the lattice Boltzmann method based on fluctuation hydrodynamics with the viscosity-modifying technique is a significantly hopeful method for simulating a magnetic suspension in a non-equilibrium situation where magnetic particles move in a flow field under a non-uniform external magnetic field together with the formation of clusters.

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Controlling the behaviour of aqueous montmorillonite suspensions through surfactant adsorption Yannan Cui 1; Claire Pizzey 2; Jeroen van Duijneveldt 1 1University of Bristol, School of Chemistry, Bristol, United Kingdom; 2Diamond light source ltd, Didcot, United Kingdom

Montmorillonite clay particles disperse well into water but tend to form gels at concentrations of a few percent by weight. Here, the suspension behaviour is modified by adsorbing amine-based surfactants onto the clay. Adsorption of polyetheramines proceeds through an ion exchange mechanism. Perhaps surprisingly, the adsorption takes place at pH conditions well above the pKa of the amine surfactants, where they are not protonated in the bulk solution. The surface coverage as a function of molar mass broadly agrees with predictions assuming adsorbed polymers adopt a densely packed mushroom configuration at the clay surface [1]. The surfactant adsorption results in a shift of the sol / gel transition to a much higher clay concentration, compared to suspensions of bare clay particles. Yet, scattering data revealed no change in suspension structure on length scales up to around a micron. Primary aggregates remain at this length scale and no liquid crystalline (nematic) phase is formed. There is however a change in structure at large length scales (of order 20 µm) where light scattering indicates the presence of string-like aggregates that disappear on addition of surfactant [2]. Modifying the clay surface using quaternary amine surfactants allowed oil-in-water Pickering emulsions to be prepared [3]. When adsorbing polyethylenimine to the particles, such droplets could be cross-linked into microcapsules [4]. [1] Y. Cui and J.S. van Duijneveldt, Langmuir 26: 17210-17217, 2010. [2] Y. Cui, C.L. Pizzey, and J.S. van Duijneveldt, to be submitted. [3] Y. Cui, M. Threlfall, and J.S. van Duijneveldt, J. Colloid Interface Sci. 356: 665-671, 2011. [4] Y. Cui and J.S. van Duijneveldt, Langmuir 28, 1753-1757, 2012

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Monte Carlo simulations of Donnan equilibrium in cartilage Jenny Algotsson 1; Torbjörn Åkesson 2; Jan Forsman 2 1Lund University, Physical Chemistry, Lund, Sweden; 2Lund University, Theoretical Chemistry, Lund, Sweden

Osteoarthritisis is a degenerative disease that affects the joints, e.g. knees and hips. It is a general conception that glycosaminoglycans (GAGs) are lost in the early stage of the degeneration of cartilage. The GAGs are highly negatively charged and are the main source of the fixed charged density (FCD) of the cartilage. To be able to follow the degeneration two non-destructive methods have been developed previously that visualize the FCD in cartilage. One of the methods uses 23Na MRI and utilizes the fact that Na+ ions are the main counterions to the GAGs and will therefore have a high concentration in the cartilage where the GAG concentration is high and vice versa. The measurement gives a distribution of Na+ ions in the cartilage, which is then related to the FCD by using ideal Donnan theory. The other method uses 1H MRI together with an intravenous injection of Gd(DTPA)2-, which is a negatively charged contrast agent that is paramagnetic and therefore affect the T1 relaxation in the tissue. The idea is that Gd(DTPA) 2- will distribute in inverse relation to the GAG concentration and by measuring the T1 relaxation in the cartilage one can determine the Gd(DTPA)2- concentration. The Gd(DTPA)2- concentration is then used to obtain the FCD of the cartilage by using ideal Donnan theory. Experimental results show that when FCD is determined by the method using 1H MRI one gets results that are a factor of 2 smaller than with the 23Na MRI method. In the presented work, we performed Monte Carlo simulations using a coarse-grained model system of the cartilage. The simulations illustrate how the determination of the FCD in the cartilage is affected by disregarding of the non-ideal contributions in the Donnan analysis. Our results show that when the non-ideal contributions in the system are taken into account the FCD determined by the Gd(DTPA)2- method is approximately a factor of 2 smaller than the FCD determined by the Na+ method.

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Ascorbic acid induced α-helix to β-sheet transition of bovine serum albumin Mohd. Sajid Ali ; Hamad Al-Lohedan King Saud University, Chemistry, Riyadh, Saudi Arabia

Effect of ascorbic acid (ASC) on the conformation of bovine serum albumin (BSA) was studied using fluorescence quenching, synchronous fluorescence and circular dichroism (CD) spectroscopies. Depending on the type of effect of ASC on macromolecule, its two concentration ranges were selected, therefore, studies were performed in very low (1 µM – 1 mM) and high (1mM – 10 mM) concentration ranges of ASC. Fluorescence quenching studies, when the sample was excited at 280 and 295 nm, in low concentration region suggested a simple ligand-albumin binding with decrease in the intensities. At high concentrations of ASC a blue shift was also observed at both excitation wavelengths. Synchronous fluorescence spectra also suggested a big change in the protein conformation as revealed by an observed large red shift at high concentrations. CD spectroscopy also favors the finding of above studies, i.e., in low concentration range the of ASC interaction was resulted in small changes in the conformation of the BSA while in high concentration range the α-helicity of the macromolecule completely disappears and the proteins seems to acquire β-sheet conformation. From the dilution of the highest concentration of ASC, used in this study, the change from α-helix to β-sheet was found to be reversible.

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Detection of heavy metal ions using water soluble conjugated polymer Marco Laurenti ; Jorge Rubio-Retama ; Enrique Lopez-Cabarcos ; Francisco Garcia-Blanco ; Paulino Alonso-Cristobal Complutense University of Madrid, Physical Chemistry II, Madrid, Spain

In this work we report the synthesis of a new water-soluble conjugated polymer, which interacts specifically with heavy metal ions such as lead and mercury. In order to produce such a material, we have combined the fluorescence properties of polythiophene, which constitutes the polymer backbone, with the chelating capacity of meso-2,3-dimercaptosuccinic acid that forms the side chain of the conjugated polymer. The new polymer acts as chemical complexing agent that quenches its fluorescence in the presence of heavy metal ions. The quenching mechanism is investigated and discussed by photoluminescence lifetime measurements. Furthermore, the Stern-Volmer constant is calculated and found to be high for Pb2+ and Hg2+ ions. In addition, we have evaluated the specificity of the polymer for these ions versus other ions such as K+, Sr2+ or Ca2+, with which no PL quenching was observed. The system presented is envisaged to be used as sensor for heavy metal ions that appear as pollutants in the environment, with high sensitivity for lead and mercury.

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Ionization by pH and anionic surfactant binding gives the same thickening effects of crosslinked polyacrylic acid derivatives Luís Alves ; Filipe E. Antunes ; Björn Lindman University of Coimbra, Chemistry, Coimbra, Portugal

Physical properties of aqueous solutions of hydrophobically modified cross-linked polyacrylates change quite extensively, as the polymer is charged up. A study is carried out concerning the similarities between two polymer ionization processes, i. e. by pH increment and anionic surfactant addition. The two processes charge the polymer by distinctly different mechanisms. At sufficiently high pH the carboxylic groups of the polymer are all virtually ionized and the polymer is, therefore, fully charged. The effective repulsion among the charged groups due to the entropy of the counterions promotes an increased stiffness as well as an expansion of the polymer particle. We investigate here how the ionization and swelling will be if, instead of high pH, the polymer is placed at low pH conditions but associated to ionic surfactants. Surfactants associate to the polymer both in a non-cooperative way by the binding of individual surfactant molecules and in a cooperative way as micelles since the polymer promotes surfactant self-assembly. This binding leads to a highly charged polymer-surfactant complex and leads to an osmotic swelling as well. The swelling and the gelation were monitored by rheology and dynamic light scattering, of polymer solutions at different pH’s and by adding ionic surfactants at low pH. The results show that ionization by surfactants and by pH lead to approximately the same gelation degree, as can be seen by similar viscosity values. Both processes result in dramatic viscosity increases, up to 8 orders of magnitude. More hydrophobic surfactants, with longer alkyl chain, are shown to be more efficient as enhancers of swelling and gelation. The network that is formed at high pH or at sufficiently high concentration of surfactant can be weakened or even disrupted if monovalent or divalent salts are added, demonstrating the role of counterion entropy.

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Assessing the properties of a DTAF-labeled hydrophilic-hydrophobic copolymer in water and surfactant micelles Alina Iovescu 1; Monika Gosecka 2; Teresa Basinska 2; Adriana Băran 1; Gabriela Stîngă 1; Stanislaw Slomkowski 2; Dan-Florin Anghel 1 1"Ilie Murgulescu" Institute of Physical Chemistry, Romanian Academy, Bucharest, Romania; 2Department of Engineering of Polymer Materials, Center of Molecular and Macromolecular Studies, Polish Academy of Sciences, Lodz, Poland

Drug delivery, nuclear medicine and antigen-antibody diagnostic tests are just a few topics in which functional microspheres found applications during the last decades. For example, emulsion polymerization of styrene with α-tert-butoxy-ω-vinylbenzyl-polyglycidol yields monodisperse microspheres with polyglycidol enriched surface that do not allow protein adsorption, and succeeded in diagnostic tests. However, little is known about the hydrophilic covering layer of these microspheres. To shed light on this, we took advantage that a minute amount of water-soluble copolymer always appears during synthesis. We recovered this copolymer and characterized it by 1H NMR and GPC. The obtained results prove that the material is the poly(styrene-polyglycidol) copolymer. We acquired further information by labeling the copolymer with 5-(4,6-dichlorotriazinyl)-aminofluorescein (DTAF) and studying its absorption and fluorescence behavior in aqueous solution without (L) and with micelles of dodecyltrimethylammonium chloride (LD), sodium dodecylsulfate (LS) and hexaethyleneglycol mono n-dodecyl ether (LE). The dianionic and anionic tautomers of the DTAF-label are apparent and agree with the recorded spectrophotometric pKa values. The quantum yields and lifetimes obey the sequence LE < LS < L < LD. They are along with the increasingly deprotonated forms of the fluorophore, and unveil that the micelle-label interactions depend on the surfactant. The work opens the way towards the design of fluorescent microspheres for medical analysis where detection in real time, with high sensitivity and accuracy is a paramount factor. Other features will be revealed during the presentation.

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Facile preparation of stabilized core- shell magnetite acrylamide-co-acrylic acid nanoparticles Hamad Allohedan ; Ayman Atta Surfactant Research Chair, Department of Chemistry, College of Science, King Saud University, Riyadh, Saudi Arabia

This work provides an insight into the preparation of magnetite polymer nanospheres with high and uniform magnetite content. The effect of incorporating of magnetite nanoparticles on the rheology of fluids will discuss. In this respect, polymer-stabilized magnetite nanoparticles were synthesized using a new process based on miniemulsion polymerization, where a stable water-based dispersion of sodium dodecyl sulfate (SDS)/ poly (2-acrylamido-2-methylpropanesulfonate (PAMPS-Na) bilayer coated magnetite aggregates was first synthesized. Monodisperse polymer coated magnetite nanoparticles Fe3O4 / poly (acrylamide-co- sodium acrylate), AM/AA, copolymer nanoparticles with diameters of 50– 500 nm were prepared by radical polymerization in the presence of a ferrofluid coated with PAMPS-Na. Extensive characterization of magnetic polymer particles by transmission electron microscopy (TEM), dynamic light scattering (DLS), zeta potential and Fourier transform infrared spectroscopy (FT-IR). FT-IR and TEM revealed that the Fe3O4 nanoparticles were incorporated into the shells of poly (AM–AA). Aqueous dispersed solutions of a charged hydrophobically modified Fe3O4/poly(AM- AA) copolymer nanoparticles exhibit high viscosities even at low polymer concentrations (0.1 wt%). Effects of temperature and addition of sodium chloride on the viscosity properties of a semi dilute dispersed solution of Fe3O4/poly poly(AM- AA) copolymer nanoparticles are examined. The results indicated that Fe3O4/poly poly(AM- AA) copolymer nanoparticles disclose strong interactions between magnetite and coated polymers of both PAMPS-Na and poly(AM- AA) copolymers.

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Biocompatibility of poly-L-lysine/heparin multilayers Alejandro Barrantes ; Thomas Arnebrant Malmoe University, Biomedical Science, Malmoe, Sweden

Polyelectrolyte multilayers (PEMs) have become very popular in recent years due to its versatility, as they can be applied in many different fields like surface1 and colloid2 modification, biosensing3, or drug delivery4. For all of these applications biocompatibility is one of the most important requirements PEMs shall fulfill. To obtain an indication of the biocompatibility of such layers, silica surfaces modified with Poly-L-Lysine/Heparin multilayers were exposed to aqueous solutions containing proteins present in body fluids. The response of the PEMs to the exposure was measured by ellipsometry depending on the outermost layer and also on the layer number. [1] G. Decher, J.D. Hong, and J. Schmitt. Thin Solid Films, 210 (1992) 831-835. [2] F. Caruso, and H. Möhwald. Journal of the American Chemical Society, 121 (1999) 6039-6046. [3] A. Yu, and F. Caruso. Analytical Chemistry, 75 (2003) 3031-3037. [4] S. De Koker, L.J. De Cock, P. Rivera-Gil et al. Advanced Drug Delivery Reviews, 63 (2011) 748-761.

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Association of Cationic Polyelectrolytes with Sodium Alkylsulphates in Aquoeus-Organic Solutions Artem Bezrukov ; Svetlana Shilova ; Alla Tret'yakova ; William Barabanov Kazan National Research Technological University, Physical and Colloidal Chemistry, Kazan, Russian Federation

Interaction of polyelectrolytes with surfactants results in formation of highly organized supramolecular structures - polymer-surfactant complexes. Such complexes are easily available models of biological systems especially when water - organic cosolvent mixtures are used to imitate real solutions in living cells. Methods of potentiometry, viscometry, spectrophotometry, NMR, conductometry and dynamic light scattering have been used to study formation and properties of cationic polyelectrolytes (quaternized poly-4-vinylpyridine, poly-N,N-dimethyl,N-benzylammoniummethylmetacrylate chloride) with anionic surfactants (sodium alkylsulfates) in mixed aqueous-alcohol (methanol, ethanol, isopropanol) solutions. The composition of aqueous-organic media has been shown to exert the prevailing influence on formation of supramolecular structures. Small ethanol and isopropanol additives (20 vol. % of ethanol and 10 vol. % of isopropanol) promote binding of sodium dodecylsulfate by polyelectrolytes. Methanol additives up to 30 vol. % do not cause any changes in surfactant binding. Complexes are represented by aggregates of macromolecules with the size range of 100 - 220 nm. Opposite effect is demonstrated by media with alcohol content above 30 vol. %. Polyelectrolyte-surfactant interactions are inhibited and stability of associates is reduced. Concentration limits for association initiation shift to higher surfactant concentrations. Alcohol content above 60 vol. % is the area ofweak polyelectrolyte-surfactant interactions because of decreased dielectric permittivity and increased affinity of solvents to nonpolar fragments of a polymer chain and surfactant molecules. Polymer-surfactant complexes are represented by single macromolecules with the radius of 20 nm. Self-organization processes in studied systems have been found to correlate with structural characteristics of mixed solvents and dual behavior of ethanol and isopropanol as cosolvents and co-surfactants.

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Polyelectrolyte gels: effect of material homogeneity on swelling Romain Bordes ; Anette Larsson Chalmers University of Technology, Department of Chemical and Biological Engineering - Applied Chemistry, Gothenburg, Sweden

Hydrogels are water–swollen networks based on cross-linked polymers systems. Many of their features, such as swelling capacity and mechanical resistance, depend on the chemical structure of the polymer, but also on the cross-linking characteristics, i.e. the distribution of the cross-linker inside the matrix. The focus of this project is to investigate the swelling degree and kinetics of polymer gels in materials made with different degrees of cross-linking heterogeneity, starting from perfectly homogeneous gels prepared by click chemistry up to non-homogeneously cross-linked systems. Generally, the click chemistry is employed to cross-link a network of polymer chains that has suitable functional groups (alkyne and/or azide). The type of modified polymers can vary from hyaluronate (1) to PVA, but also highly charged polyelectrolytes such as polyacrylic acid (PAA). Following this principle, the formation of gels will be based on PAA that will be modifed via classical coupling chemistry in order to get alkyne and azide covalently attached to the chain. EDC/NHS modifications have been carried out successfully for other purposes on PAA (2) and others polyelectrolytes previously. The cross-linking will then be carried out by the use of a proper catalyst. Furthermore, once the polymer functionalized with alkyne groups, it is also possible to consider the use of diazide, i.e. polyoxyethylene bis(azide), as a cross linker, thus playing on the size of the cross linker. (1) Crescenzi, V.; Cornelio, L.; Di Meo, C.; Nardecchia, S.; Lamanna, R. Biomacromolecules 2007, 8, 1844-1850. (2) Wang, C.; Yan, Q.; Liu, H.-B.; Zhou, X.-H.; Xiao, S.-J. Langmuir 2011, 27, 12058-12068.

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Mixtures of chitosan and oppositely charged alkyl ethoxy carboxylates:How surfactant micelles affect the structure of polyelecte Leonardo Chiappisi ; Michael Gradzielski Technische Universität Berlin, Stranski-Laboratorium für Physikalische Chemie und Theoretische Chemie, Berlin, Germany

Mixtures of polyelectrolytes and surfactants are widely used in a large number of fields, such as detergency, pharmaceutical formulations, food industry, etc. The structures which are found in aqueous solution are various and highly complex. Intensive research was performed in order to find systematic relations between the structure of the complexes and physical parameters of the components (charge density, size of the macroion, flexiblity of the macromolecular chain). Here, we present a comprehensive structural study on mixtures of the semiflexible biopolycation chitosan and a series of highly biocompatible alkyl ethoxy carboxylates, which differ by their alkyl chain length and ethylenoxide content. In this way it was possible to systematically change the size and shape of the surfactant aggregate without changing any external parameter such as pH, temperature, etc. and without affecting the surfactant-chitosan unit interaction. Experiments were performed over the cmc and the overlap concentration of the polymer. Our investigation addresses the question of how the ratio surfactant/polyelectrolyte and the total concentration affect the structure and dynamics of the surfactant/polyelectrolyte complexes. For this purpose, static and dynamic light scattering (SLS and DLS) and small angle neutron and x-ray scattering (SANS, SAXS) experiments were performed. The results show that the shape of the micelle is retained within the complex and that the final structure is determined by the surfactant aggregate size to polymer persistence length (lp) ratio. For values above 1, i.e. for large aggregates compared to the lp, the polymer network is disrupted. If small micelles are added to the polymer solution they will be incorporated into the network forming a hierarchically built complex system. In general, there exist systematic correlations between the molecular composition of the complexes and their mesoscopic structure and dynamics, which can be employed further for having functional materials with the physiochemical properties of the components for purposes of selective solubilisation and as delivery systems.

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Coacervated recombinant mussel adhesive proteins as a model system of complex coacervates for biomedical applications Yoo Seong Choi 1; Seonghye Lim 2; Hyung Joon Cha 2 1Chungnam National University, Department of Chemical Engineering, Daejeon, Republic of Korea; 2Pohang University of Science and Technology, Department of Chemical Engineering, Pohang, Republic of Korea

Mussel adhesive proteins (MAPs) have been recognized as very attractive biomaterials in biomedical applications, based on their non-toxic and strong attachments for various inorganic and organic substrates even in wet environment. Complex coacervates have been considered as a model of the condensation and non-water dispersed adhesion process of MAPs, although it has not been possible to experimentally validate the coacervation model due to the difficulty to obtain purified MAPs. Previously, we successfully produced recombinant MAPs using recombinant DNA technology. Here, we show complex coacervation using MAPs and other partner polyelectrolytes. The highly condensed complex coacervates significantly increased the bulk adhesive strength of MAPs in both dry and wet environments. Oil droplets were successfully engulfed using a MAP-based interfacial coacervation process, to form microencapsulated particles. We expect this system can be also used a good model system of complex coacervates for biomedical applications. Experimental results and discussion will be presented.

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Study of mechanical properties of dendronized polymers at single molecule level Lucie Grebikova 1; Laura Muresan 1; Plinio Maroni 1; Baozhong Zhang 2; A. Dieter Schlüter 2; Michal Borkovec 1 1University of Geneva, Department of Mineral and Analytical Chemistry, Geneva, Switzerland; 2ETH Zurich, Department of Materials, Zurich, Switzerland

Dendronized polymers have attracted considerable scientific interest in recent years. They consist on a central linear polymeric core with appendent dendrons and attain a rod-like, cylindrical shape [1]. Polymethacrylate-based dendronized polymers of different generations (PGn) adsorbed on a chemically modified mica substrate were imaged with atomic force microscopy (AFM) in solution. Mechanical properties of individual dendronized polymers were investigated using single-molecule force spectroscopy (SMFS) by manipulating single polymer chains in solution. The force measurement was performed directly after imaging on the precise position on the molecule. The measured force-distance curves using AFM-based SMFS revealed a detailed insight into material properties at the molecular level. The generation dependence investigation puts in evidence the unique behavior of PG5 where the particular polymer conformation (pearl-necklace structure) induces different adsorption properties in comparison with the lower generations. While PG1-PG4 show single force events (peeling and pulling), PG5 presents multiple pulling events and two peeling forces. [1] Schlüter, A. D. et al. Dendronized Polymers: Synthesis, Characterization, Assembly at Interfaces, and Manipulation. Angewandte Chemie Int. Ed. 39(5), 864-883 (2000).

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Deposition of structured polymer-surfactant particles onto different substrates – a study using time-resolved ellipsometry Charlotte Gustavsson 1; Lennart Piculell 1; Ola Karlsson 2 1Lund University, Physical Chemistry, Lund, Sweden; 2MIP Technology AB, Lund, Sweden

Structured polymer-surfactant particles of well-defined shapes and sizes may form spontaneously when mixing a surfactant and polymer of opposite charge in water1. The polyion, which can be seen as a multivalent counter-ion, condenses the charged surfactant aggregates to form water-insoluble phases with structures that can be tuned by choice of the components and concentrations in the mixture. An attractive possibility is to deposit such insoluble polymer-surfactant particles onto surfaces to form porous surface layers. Such layers have a wide range of potential applications, including selective barriers between phases, reservoirs or adsorbing sinks2. We have looked at the deposition of structured particles formed when mixing alkyltrimethylammonium bromides of different alkyl chain lengths (C12 or C16) with sodium polyacrylate. Time-resolved ellipsometry was used to follow the deposition of the particles onto silica surfaces, including cationically or hydrophobically modified silica surfaces. In order to check the reversibility of the adsorption, rinsing was employed after the particles had been adsorbed. In addition to altering the surfaces, various strategies were used to modify the properties of the particles. For instance, the ratio between polymer and surfactant in the particles was varied, yielding particles with either a negative or a positive surface charge, thus changing the affinity for the different substrates. [1] Nizri, G.; Makarsky, A.; Magdassi, S.; Talmon, Y. Langmuir, 25, 2009, 1980-1985 [2] Piculell, L.; Norrman, J.; Svensson, A.; Lynch, I.; Bernardes, J.S.; Loh, W. Adv. Colloidal Interface Sci. 147-148, 2009, 228-236

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Segregation and mixing of proteins in polyelectrolyte gels Per Hansson ; Jonas Gernandt Uppsala University, Pharmacy, Uppsala, Sweden

Results will be presented showing that different proteins, or macroions employed as models of proteins, either mix or segregate from each other when confined to a polymer gel network of opposite charge to the proteins. The results indicate that the outcome depends on the difference in charge density of the proteins/macroions and that under conditions of competitive binding one protein can also be excluded from the gel particle. Different segregation mechanisms driven by polyion-mediated interactions between protein molecules and protein aggregation will be discussed. The experimental results will be complemented with results from recent theoretical investigations of phase separation in polyelectrolyte gels. The relevance of the results both for understanding the poorly understood process of protein sorting in the Golgi apparatus of protein secretory cells and the encapsulation of protein and peptide drugs in microgel drug delivery particles will be discussed.

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Temperature-induced transition from odd–even to even–odd effect in polyelectrolyte multilayers Peter Nestler ; Stephan Block ; Chrisitiane A. Helm Greifswald University, Greifswald, Germany

Within a liquid cell the linear growth of polyelectrolyte multilayers from poly(styrenesulfonate) (PSS) and poly(allylamine hydrochloride) (PAH) is observed with multiple angle null ellipsometry. The salt content is varied between 1 and 4 mol/L NaCl and the temperature between 20 and 55 °C. In the linear growth regime, the outermost layer is investigated. At low temperature, a top PSS layer is twice as thick as a top PAH layer (odd–even effect), consistent with the respective monomer volumes and the same water content for both kinds of top polyelectrolyte layers as confirmed by refractive index measurements. On heating, the thickness of a polycation/polyanion bilayer increases. For temperatures exceeding a crossover temperature, a top PAH layer is thicker than a top PSS layer (even–odd effect). Simultaneously, the index of refraction of the respective top layers indicates a compact PSS and a swollen PAH layer. It is suggested that, at elevated temperature and high salt conditions, secondary forces gain importance in comparison to electrostatic forces: therefore, a transition from an odd–even to an even–odd effect occurs, as well as the decreased film stability on drying as described before (Cornelsen, M., et al. Macromolecules 2010, 43, 4300). The ellipsometric data indicate that PAH/PSS layer pairs exceeding 8.6 nm thickness in solution are unstable in air.

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Theoretical studies of intrinsically disordered proteins in solution and adsorbed to surfaces Marie Skepö ; Mikael Lund ; João Henriques Lund University, Theoretical Chemistry, Lund, Sweden

The existence of functional disordered proteins (IDPs) has been recognized for many years now. However, due to the classical structure-function paradigm, the functional role of IDPs has only recently been recognized. Among the increasing number of recognized IDPs there is a family of related, neutral and basic, histidine-rich proteins, denominated histatins. These proteins are present in human parotid and submandibular-sublingual excretions and are known to adhere to and inhibit the formation of hydroxyapatite, enhance the glycolytic activity of salivary flora, possess antibacterial and antifungal properties, and to precipitate condensed tannins. Histatin 5 is a small protein (24 amino acid residues) with particularly interesting clinical (highest candidacidal activity of all histatins) and modelling properties (contains 7 histidine residues which give rise to charge regulation effects at physiologically relevant pH values). Despite its obvious importance in the nonimmune oral host defense system, there are only a few reports on the secondaty structure and structure-function analyses. In order to better understand the mechanisms by which histatins function we decided to perform simultaneous theoretical and experimental studies on histatin 5, which will be used as a reference model for the histatin family. Theoretical studies involve constant-pH atomistic molecular dynamics and coarse-grained Monte Carlo simulations of this protein in explicit aqueous solution, testing different pH values, salt concentrations and valencies, and temperature. Preliminary results show good agreement between the radius of gyration and the average charge for both methods. Next, we will focus on the coarse-grained model to study the interactions between histatin 5 molecules in the absence and presence of explicit mono- and divalent ions, as well as the adsorption of histatin 5 to surfaces, and complexation with tannins. Circular dichroism and size exclusion chromatography studies will be conducted to verify and complement theoretical information regarding the secondary structure as an effect of solution properties and protein self-assembly, respectively.

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The influence of tetraalkylammonium bromides on the complexation behavior between poly(N-vinyl pyrrolidone) and sodium dodecyl sulfate Sheng-Shu Hou National Cheng Kung University, Department of Chemical Engineering, Tainan, Taiwan

Even, in the presence of Me4NBr or Et4NBr, the occurrence of cross-peak between SDS protons and PVP protons are all the same with that in the salt-free solution as shown in Figure 3b and 3c, respectively. Thus, whether those ammonium salts are added into PVP/SDS solution, PVP chain still penetrates into the SDS aggregate deeply. Corresponding with the same I1/I3 ratio in the plateau, the microstructure of PVP/SDS aggregate is unchanged. However, in the presence of Pr4NBr or Bu4NBr, pyrene fluorescence shows that the [SDS]/[R4NBr] ratio determines the formation of SDS aggregate (for Pr4NBr, >0.6 ; for Bu4NBr, >1.0). In Figure 4a and 4b, 13.2 mM Pr4NBr and 13.2 mM Bu4NBr are added into 5 mM SDS and 10 mM SDS solution with 10 g/L PVP, respectively. Since both compositions are less than the critical ratio, relating to the region II in the pyrene I1/I3 plot, we suggest that SDS molecules do not interact with PVP. As described above, no cross-peaks between SDS protons and PVP protons could be found in in Figure 4a and b. This is the strong and direct evidence that the SDS molecules do not associate with PVP to form the PVP-SDS complexes.

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Role of polymer-nanofiller interaction for polymer electrolyte dynamics Benson K. Money 1; K. Hariharan 2; Jan Swenson 1 1Chalmers University of Technology, Department of Applied Physics, Goteborg, Sweden; 2Indian Institute of Technology, Madras, Department of Physics, Chennai, India

Poly(ethylene oxide)-based electrolytes, in general, exhibit too low ionic conductivities for many battery applications. The low conductivity is partly because of their semi-crystalline nature, since the migration of the mobile salt ions (often Li+) is believed to occur predominantly in the amorphous phase. Different approaches have been used to improve the ionic conductivity of ordinary polymer electrolytes. One of these approaches, which furthermore improves the mechanical stability of the solid electrolyte, has been to add nanoparticles, so called fillers, to the polymer electrolyte. However the final properties of these composite polymer electrolytes are strongly dependent on the nature (attractive or non-attractive) of the surface active groups present on the fillers. In the case when ‘non-attractive’ δ-Al2O3 nanofillers are added to the PEO-LiClO4 system we show that the calorimetric glass transition temperature decreases at the same time as the ionic conductivity increases. Since the decrease in glass transition temperature is expected to be associated with an enhanced relaxation rate of the viscosity related α-relaxation, i.e. a speeding up of the segmental polymer dynamics, the results indicate a direct coupling between Li+ ion motions and segmental polymer dynamics in the case when ‘non-attractive’ δ-Al2O3 nanofillers are added (at least for concentrations up to 4 wt%). These findings will be compared with the case when ‘non-attractive’ (fumed SiO2) nanofillers are introduced to the PEO-LiClO4 system, with the aim to understand how the nature of the polymer-nanofiller interaction affect the glass transition temperature, ionic conductivity and dielectric relaxations of PEO-LiClO4 polymer electrolytes.

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Multilayer polymer films as functional membranes and coatings for nanocapsules in application for molecular biomedicine Katarzyna Kilan ; Lilianna Szyk-Warszyñska ; Krzysztof Szczepanowicz ; Piotr Warszyñski Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, Cracow, Poland

Targeted therapy requires new specific ways to administer drugs. Polymeric nanocontainers are good candidates for this purpose. Selection of polymer coatings is an important stage in design of nanocariers. They should be non-toxic, with minimal interaction with immune system (stealth effect) allowing easy modification with targeting ligands. We have chosen biocompatible, natural polyelectrolytes to obtain ultrathin membranes, which can be used as shells of the hydrophobic core nanocapsules obtained by layer-by-layer adsorption (LbL). LbL is versatile method to prepare multilayered polymeric films on both macroscopic surfaces and nano- or micro-objects. Changing type of polyanion/polycation pair, number of layers and conditions of their deposition, thickness, permeability and type of surface chemistry can be easily adjusted. We obtained multilayer films constructed with biocompatible and natural polyelectrolytes (e.g. poly-L-arginine, modified pullulan, alginate). During formation of multilayers they were contacted with solutions having various ionic strength and salts. We determined the adsorbed mass, viscoelastic properties and thickness of films using QCM-D and ellipsometry. The electrochemical techniques (cyclic voltamperometry, electrochemical impedance spectroscopy) were applied to determine their permeability. For the poly-L-arginine/alginate multilayers we observed strong dependence of mass and thickness of the films on the concentration of calcium ions in rinsing solution which is explained by crosslinking of alginate. We correlated the permeability of the polyelectrolyte membranes with their thickness and degree of crosslinking. Acknowledgement: This work was financially supported from the project Interdisciplinary PhD Studies "Molecular sciences for medicine" (co-financed by the European Social Fund within the Human Capital Operational Programme) and COST action CM 1101.

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Cononsolvency in aqueous solutions of P(S-b-NIPAM) diblock copolymers Martine Phillip 1; Joseph Adelsberger 1; Sebastian Jaksch 1; Anna Miasnikova 2; André Laschewsky 2; Isabelle Grillo 3; Peter Müller-Buschbaum 1; Christine Papadakis 1; Konstantinos Kyriakos 1 1Technische Universität München (TUM), Physikdepartment, Physik weicher Materie, Garching b. Munich, Germany; 2Universität Potsdam, Fakultät für Chemie, Potsdam, Germany; 3Institut Laue-Langevin, Grenoble, France

Thermoresponsive hydrogels have attracted a lot of attention as switches. The most prominent polymer in this class, PNIPAM, has a lower critical solution temperature (LCST) of 32 oC. Moreover, PNIPAM exhibits the cononsolvency effect, i.e. a miscibility gap upon addition of a second polar solvent, e.g. methanol [1]. Diblock copolymers consisting of a long thermoresponsive PNIPAM block and a short hydrophobic polystyrene block (P(S-b-NIPAM)), are of great interest regarding their tendency to form core-shell micelles in aqueous solution with a thermoresponsive shell [2]. We report here on an investigation of the shell collapse and the subsequent aggregation. In a stopped-flow experiment with time-resolved SANS, d-MeOH was added in various mixing ratios to micellar solutions of P(S-b-NIPAM) diblock copolymers in D2O. For all chosen solvent ratios, the shell collapse is faster than 0.1 s, and the growth of clusters follows a logarithmic growth law.

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Slippery surface nanoparticles for enhanced mucus penetration Flavia Laffleur ; Andreas Bernkop-Schnürch University of Innsbruck, Department of Pharmaceutical Technology, Innsbruck, Austria

The aim of this study was to investigate the mucus-penetrating properties of neutral nanoparticles comprising polyacrylic acid (PAA) and polyallylamine (PAM).Three types of nanoparticles were prepared. PAA nanoparticles and PAM nanoparticles were obtained by ionic gelation with calcium ions and tripolyphosphate, respectively. Polyacrylic acid and polyallylamine nanoparticles were prepared on the basis of ionic interactions between the two polymers. All nanoparticles were loaded with fluorescein diacetate as a fluorescence marker. The PAA-PAM nanoparticles were further characterized by measuring the particle size via dynamic light scattering and transmission electron microscopy as well as surface charge. The cytotoxicity was examined via resazurin and LDH assay. A modified ussing chamber mounted with native intestinal porcine mucus was used to study the diffusion properties of obtained neutral nanoparticles compared to control particles. The obtained neutral particles displayed smooth and spherical surface with a particle size range of 200 nm and a zeta potential of 0.9 mV. The neutral PAA-PAM nanoparticles demonstrated no significant cytotoxicity on Caco-2 cell monolayers. The diffusion efficiency of neutral nanoparticles through native mucus was 2.5-fold and 1.8-fold higher than PAM and PAA nanoparticles, respectively.Taking enhanced mucus-penetrating properties into account, the neutral surface turned to be slippery. Therefore neutral nanoparticles were shown to be very promising in drug delivery via mucus membranes of different cavities.

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Searching for the mechanism of fluorescence quenching by cytochrome c in conjugated polymers Marco Laurenti 1; Maria Isabel González Sanchez 2; Maria Pilar De Diego Vindel 1; Edelmira Valero 2; Jorge Rubio Retama 1; Enrique López Cabarcos 1 1Universidad Complutense de Madrid, Department of Physical Chemistry II, Madrid, Spain; 2Universidad de Castilla-La Mancha, Department of Physical Chemistry II, Albacete, Spain

The process of fluorescence quenching can occur through different mechanisms, even though only three of them are dominant, namely: electron transfer, resonance energy transfer, and intersystem crossing [1]. It has been reported that cytochrome c (cyt c) quenches the fluorescence of the conjugated polymer poly[5-methoxy-2-(4-sulfobutoxy)-1,4-phenylenevinylene] (MBL-PPV) and that the Stern-Volmer constant (Ksv), that quantifies the luminescence quenching, exhibits a value as high as 108. The mechanism proposed to explain this phenomenon is the electron transfer between the cyt c and the MBL-PPV polymer [2], which relies on the reduction of the iron of the porphyrin ring of cyt c from Fe(III) to Fe(II). Liu et al. reported that the fluorescence quenching of polyelectrolytes does not involve electron transfer or energy transfer but is the result of conformational changes that occur upon binding the polyelectrolyte to the protein [3]. Xing et al. develop a new material that is effective in killing bacteria based on an anionic polythiophene and a cationic porphyrin [4] that can perform energy transfer from the polymer to the porphyrin upon irradiation under white light. With the aim to investigate the quenching mechanism of conjugated polymers by proteins, we studied the fluorescence quenching of the water-soluble poly[5-methoxy-2-(4-sulfopropyloxy)-1,4-phenylenevinylene] (MPS-PPV) by cyt c Fe(III) and cyt c Fe(II). In addition, we investigated the quenching of MPS-PPV by porphyrin derivatives such as: Hemin, protoporphyrinIX, and 5,10,15,20-Tetrakis(4-trimethylammoniophenyl)porphyrin tetra(p-toluenesulfonate). The results obtained seem to indicate that the fluorescence quenching of the MPS-PPV by cyt c Fe(III) doesn’t rely on the mechanism proposed by Fan. We propose that the fluorescence quenching is the result of two cooperative mechanism and we quantify the percentage contribution of each mechanism to the fluorescence quenching of the MPS-PPV.

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Long-term modification of a polymer microfluidic device for easy chromosome spreading Olga Mednova ; Dorota Kwasny ; Kristoffer Almdal ; Winnie Svendsen Technical University of Denmark, Micro- and Nanotechnology, Lyngby, Denmark

Nowadays, Fluorescent In Situ hybridization (FISH) is becoming a popular technique for effective chromosomal abnormalities detection in cytogenetic analysis. Easy chromosome spreading is a determinant aspect and can be influenced by many factors such as temperature, humidity, a fixative solution evaporation rate as well as hydrophility of the surface. Due to fabricate fast, cheap and universal microfluidic devise for FISH analysis TOPAS - cyclic olefin copolymer (COC) is applied. However, wetability of TOPAS is desired to be increased significantly. Various COC surface modification techniques have been suggested and well described in literature [1]. In the current research oxygen plasma pretreatment with 4 minutes UV-initiated 2-hydroxyethyl acrylate (2HEA) grafting afterwards has been investigated and long-term storage prospective was examined. Mentioned modification technique improved hydrophilic properties up to (42.8±2.2) of water contact angle which remained at the same level during next 14 days and was sufficient for cell spreading. It is worth of note that both plasma and grafting conditions are influence a lot on resulting wetability. Plasma duration influence on initial hydrophility level mostly. Noteworthy, drift of contact angle in the period of first days was detected. During shelf storage the steady growth was noticed with final reaching a contact angle around 60° in next 40 days. Interesting observation has been made by comparing surface effects of air and oxygen plasma. Probably due to formation of critical number of polar functional groups in both cases no differences in contact angles have been observed between slides and hydrophility changes with similar curve behavior. A microfluidic device treated with described method was fabricated and tested [2]. Acknowledgments: Support for this work was provided by VKR-foundation financed centre NAMEC. References: [1] P.S.Nunes, P.D.Ohlsson, O.Ordeig, J.P.Kutter; Microfluid Nanofluid (2010) 9:145-161; [2] D. Kwasny, I. Vedarethinam, O. Mednova, A. Silahtaroglu, Z. Tumer, M. Dimaki, Kr. Almdal, W. E. Svendsen; Lab On a Chip European congress 2012, Edinburgh, Scotland

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Impact of denaturants on the dynamic surface properties of globular protein solution Alesya Mikhailovskaya 1; Egor Nikitin 1; Boris Noskov 1; Shi-Yow Lin 2; Giuseppe Loglio 3; Reinhard Miller 4 1Saint-Petersburg State University, Saint-Petersburg, Petergof, Russian Federation; 2National Taiwan University of Science and Technology, Taipei, Taiwan; 3Universita degli Studi di Firenze, Firenze, Italy; 4MPI fuer Kolloid- und Grenzflaechenforschung, Golm, Germany

The existing surface analytical techniques do not allow detailed investigation of the protein conformation at liquid-fluid interfaces. The extent of the protein globule unfolding in the course of adsorption is still a subject of intensive discussions. It has been shown recently that conformational transitions in the protein adsorption layer influence strongly the kinetic dependencies of the dilatational surface elasticity [1, 2]. The increase of the guanidine hydrochloride (GdnHCl) concentration up to a critical value results in a local maximum of the surface elasticity indicating the destruction of the both protein tertiary and secondary structures. The methods of surface rheology were applied in this work to investigate the unfolding of β-lactoglobulin (BLG) and bovine serum albumin (BSA) globules at the solution – air interface under the action of urea. In the case of globule adsorption the dynamic surface elasticity increases monotonically with the surface age and reaches high values (~70 mN/m). The increse of the urea concentration leads to the acceleration of the surface elasticity growth. If the urea concentration is higher than a critical value, the kinetic dependencies of the dynamic surface elasticity have a local maximum indicating the formation of the distal region of the surface layer (the region of loops and tails). The surface pressure corresponding to the maximum of the surface elasticity does not depend on the denaturant concentration and is the same for different denaturants (urea, GdnHCl, ionis surfactants) [3]. This characteristic value is about 19 mN/m for BLG solutions and 14 mN/m for BSA solutions. This work was financially supported by the Russian Foundation of Basic Research (Project RFBR 1 11-03-00801_a). References: [1] Noskov, B. A.; Grigoriev, D.O.; Latnikova, A.V.; Lin, S.-Y.; Loglio, G.; Miller, R. J. Phys. Chem. B, 2009, 113, 13398. [2] Noskov, B. A.; Mikhailovskaya, A. A.; Lin, S.-Y.; Loglio, G.; Miller, R. Langmuir, 2010, 26, 17225. [3] Mikhailovskaya, A. A.; Noskov, B. A.; Lin, S.-Y.; Loglio, G.; Miller, R. |J. Phys. Chem. B, 2011, 115, 9971 |

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Stabilization of emulsion by polyelectrolyte/surfactant mixtures Altynay Sharipova 1; Saule Aidarova 1; Reinhard Miller 2 1Kazakh national technical university named after K.I.Satpayev, Almaty, Kazakhstan; 2Max-Planck Institute of Colloids and Interfaces, Potsdam, Germany

One of the actual topics of colloid chemistry is the stability of disperse systems, such as emulsions, which have practical applications in various branches of industry. According to Rehbinder an important factor in emulsion stabilization is the structural-mechanical factor which can be provided by mixtures of polyelectrolyte with surfactant. They reduce the interfacial tension and thereby increase the stability of the emulsion. Polyelectrolyte/surfactant mixtures have high viscosity and mechanical durability due to structure formation in the interfacial adsorption layer. In this regard it is interesting to study the features of their interfacial adsorption layer formation. The present work is devoted to the study of interfacial tension of mixtures of the cationic polyelectrolyte- polyallylamine hydrochloride/surfactant-sodium decylsulphate at water/hexane interface and establish correlations with stabilization parameters. It was found that the interfacial tension isotherm of polyelectrolyte/surfactant mixtures is shifted to lower concentrations in comparison with pure surfactant and polyelectrolyte. A direct correlation between interfacial tension and stabilization effects was established.

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Investigation of the pH dependent Poly(acrylacid)/Porphyrin complex formation Sebastian Orban ; Monika Schönhoff WWU Muenster, Physical Chemistry, Münster, Germany

Bringing together oppositely charged polyelectrolytes under appropriate conditions, such as their mixing ratio, amount of salt, pH etc., leads to the formation of polyelectrolyte complexes (PEC’s). Polyelectrolytes and their complexes are objects of current research and already found numerous applications in industry and economy. In particular, pH tunable systems are interesting for controlled release applications. Here, we study a model system consisting of the weak polylacid poly(acrylacid) (PAA) and a cationic porphyrine derivative (Por4+). Initially, the size of the formed complex is of interest, which is studied by Dynamic Light Scattering (DLS) and PFG-NMR under variation of the pH, amount of salt and mixing ratio. Here we can show the point of charge neutralization in titration experiments. The size of PAA/Por complexes shows three significant regions in dependence on their mixing ratio (decreasing, constant and increasing hydrodynamic radii). Furthermore thermodynamic parameters such as enthalpy (ΔH) and entropy (ΔS) are obtained via Isothermal Titration Calorimetry (ITC). Possible π-π-stacking and the formation of H- or J-aggregates are investigated using UV-Vis. The polyelectrolyte complex formation is an exothermic process. Both ITC and UV-Vis results are indicating the formation of H- and/or J-aggregates in solution due to changes in the enthalpy or the absorption bands, respectively. We find that the type of complex formed and the interaction enthalpies are strongly influenced by pH.

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Influence of magnetic field on adsorption of PEI on hematite Jacek Patkowski University of Maria Curie Sklodowska, Radiochemistry and Colloid Chemistry, Lublin, Poland

Adsorption of polymers is a very important and complex issue. It significantly differs from adsorption of small molecules and inorganic ions. A research on adsorptive and electrokinetical properties of polymeric substances have a lot of practical applications connected with the following branches of industry: food, paint, cosmetics and technological processes used in environment protection, just to name a few. There are many factors that influence adsorption of polymers. These include: pH of the solution, surface area and type of adsorbent, ionic strength. One of the least researched factors that also influence an adsorption process is magnetic field. As a general rule, it should influence adsorption of charged (ionic) polymers as well as magnetic adsorbents. Therefore a presented research discusses the influence of magnetic field on adsorption of polyethyleneimine on hematite. The polymer used is a commercially available polyethyleneimine (PEI) of molecular weight 25 000. It was adsorbed in its natural pH (between 8 and 9) on commercial hematite Fe2O3. A background electrolyte was 10-2M NaCl. Analysed system was put in various magnetic fields, ranging from 0.1T up to over 0.4T. Only neodymium magnets were used. For obtaining the adsorption amount, a UV-VIS spectrometry was used, with the help of a reaction between PEI and copper ions. The method was developed by our research group. In order to fully analyse and understand the presented system, a whole set of measurements was obtained: adsorption, kinetic, zeta potential, particle size, AFM photos of surface of hematite with and without adsorbed polymer. The adsorption of PEI is both magnetic field-sensitive and has a multi-layer character. Results from both adsorption and kinetic measurements show, that a general trend is that a stronger magnetic field decreases the adsorption amount of PEI on hematite. In kinetic measurements, this was also confirmed. The results are fully analysed and early conclusions concerning adsorption mechanism and kinetics are presented.

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Sacrificial bonds between surfaces coated with PEC and PEM containing nanoparticles Caroline Ankerfors 1; Erik Johansson 2; Lars Wagberg 2; Torbjorn Pettersson 2 1EKA Chemicals AB, Bohus, Sweden; 2KTH Royal Institute of Technology, Fibre and Polymer Technology, Stockholm, Sweden

The aim in this study was to prepare polyelectrolyte complexes (PECs) that can generate sacrificial bonds between surfaces treated with these PECs, similar to the sacrificial bonds found in e.g. human bone. Therefore, particle polyelectrolyte complexes (PPECs) were formed by mixing cationic polyacrylamide (CPAM) and silica nanoparticles using a jet mixing technique, resulting in stable cationic PPECs in a size range of 100 to 300 nm in diameter. The adsorption of the PPECs to silica was studied with QCM-D, showing that smaller PPECs adsorbed to a higher level than larger PPECs. This is ascribed to the higher diffusion speed of smaller complexes compared to the larger ones, since the PPECs are competing for surface access with the free CPAM in the solution. Adsorption studies of the same components as in the PPECs, but in particle polyelectrolyte multilayer (PPEM) structures showed a stable, gradual build-up of material on the surface when using small nanoparticles, whereas PPEMs comprising elongated nanoparticles appeared to create less rigid PPEM at the surface when nanoparticles were in the outermost layer. This phenomenon is ascribed to repulsive forces within the adsorbed layers. AFM colloidal probe technique was used to study interaction between surfaces coated with PPECs, PPEMs, or polyelectrolyte complexes (PECs). The results showed that, as expected, long range disentanglement can be achieved with PPECs but in general the pull-off forces were low. Treatment with PPEMs comprising the same polymer and nanoparticle components as the PPECs generated higher pull-off values, together with a disentanglement behaviour. The PECs displayed higher adhesion but no disentanglements.

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Xanthan gelation Alois Popp ; Alexis Paul ; Ruud den Adel Unilever R&D, Vlaardingen, Netherlands

Xanthan gum is a water-soluble extracellular polysaccharide and an important industrial biopolymer. As a polyelectrolyte, its solution behaviour is influenced by the presence of salt. Xanthan is often used as a thickening agent, forming liquid crystalline phases in the absence of salt, or random polymer networks of low elasticity upon salt addition. Here, we report for the first time formation of highly elastic gels of xanthan, enabled by the presence of the monovalent salt sodium thiocyanate. Influence of biopolymer concentrations and ionic strength on rheological behaviour have been investigated for this salt. We conclude that this specific behaviour can not be achieved by other salts. Also, possible effects of Xanthan gelation on mixed Xanthan- containing systems in sodium thiocyanate are discussed. Gelation and structural details have been traced by rheology, light scattering, AFM and synchrotron SAXS.

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Challenges in the measurement of protein zeta potential Mark Pothecary ; Paul Clarke ; Michael Kaszuba ; Ciaran Murphy Malvern Instruments Ltd, Malvern, United Kingdom

It is a scientific irony that some of the most common biopolymers, proteins, are so rarely thought of in this way. However, as molecules of varying length and molecular weight made up of repeating units (amino acids), proteins are polymers in a very real sense. The only major difference is that an individual protein is made from a selection of different amino acids whereas a typical synthetic or natural polymer will be made up of only one or two repeating monomers. When considered as a different class of polymer, it is clear that the classical parameters used to characterise polymers will also be relevant to proteins. One parameter that determines how colloids and polymer solutions behave is zeta potential. Recently, protein zeta potential has been investigated more widely as it can be used to study the stability and the viscosity of protein formulations. This is particularly important as protein drugs, or biopharmaceuticals, are widely used and the behaviour of biopharmaceutical formulations is of increasing concern. Measurement of protein zeta potential has, up to now, been difficult. Few light scattering based instruments have the sensitivity to make such measurements. Furthermore, the application of an electric field during a zeta potential measurement can damage the protein sample by stimulating aggregation. The measured zeta potential is then more closely related to the zeta potential of the protein aggregates rather the protein itself. High quality measurements of protein zeta potential have a number of key requirements including: an instrument with sufficient sensitivity to measure both the low count rates and low electrophoretic mobilities associated with dilute protein solutions; a measurement technique that minimises the risk of the measurement stimulating the generation of protein aggregates; a measurement protocol that both minimises the risk of protein aggregation and identifies whether aggregation has occurred. With these requirements satisfied, high quality zeta potential measurements become possible. This talk will describe how recent hardware and method developments have helped to improve the accuracy of such measurements.

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Hydrogel analysis by microrheology in the drug delivery field Roland Ramsch Formulaction, L'Union, France

This work presents a new technique of the passive microrheology for the study of the microstructure properties of soft materials like emulsions. Our technology uses Multi Speckle DWS (MS-DWS) set-up in backscattering with a video camera. It allows to measure the mean displacement of the microstructure particles in a spatial range between 0,1 and 100 nm and a time scale between 10-3 and 105 seconds. Different parameters can be measured or obtained directly from the Mean Square Displacement (MSD) curve like a fluidity index, an Elasticity Index, a Macroscopic Viscosity Index, a relaxation time, a MSD slope. This technique allows to monitor the evolution of the microstructure, the restructuration after shearing, the variation of the viscoelastic properties versus temperature, pH, the physical stability of emulsion or suspension... This work focuses on the measurement of viscoelastic properties evolution of an hydrogel which is sensitive to pH. The first step consists in following the gel formation and the second one the swelling of the gel. The microrheology measurement enables to follow the gel point and the evolution of the ratio between solid and liquid character.

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Stretchable silicone-supported hydrogel for mechanotransduction systems Cesar Rios 1; Cedric Vogt 2; Loic Jierry 1; Fouzia Boulmedais 1; Philippe Lavalle 3; Pierre Schaaf 1 1Institut Charles Sadron- CNRS, Strasbourg, France; 2Institut National de la Sante et de la Recherche Medicale, INSERM, Biomaterials and Tissue Engineering, Strasbourg, France; 3Institut National de la Sante et de la Recherche Medicale, INSERM, Strasbourg, France

Recently studies have demonstrated that macroscopic mechanical forces can lead to changes at the molecular level which creates new tools for organic and materials chemist [1-3]. Mertz et al. prepared the first catalytic material triggered by stretching: a phosphatase-enzyme was incorporated into a polyelectrolyte multilayer film deposited on silicone elastomer [4]. In this work we would like to present the study of polyacrylamide (PAM) hydrogels on a polydimethylsiloxane (PDMS) surface that could be used in mechano-sensitive systems. The first step is the study of the activation of the PDMS surface, a transparent elastomer, on which we will form the hydrogel. This inert surface is activated using UV-Ozone treatment. From contact angle and infrared data we optimized the time for surface activation. The PDMS is then functionalized with acrylates. A mixture of acrylamide and bis-acrylamide is poured on this surface and left to polymerize by radical polymerization overnight. This results in a transparent well attached hydrogel on the PDMS confirmed by the study of stretching of the system. The hydrogel is not removed from the substrate even after high stretching rates, bending, drying or swelling of the system. This system of PAM hydrogel on silicone could be used as an ideal candidate to design mechanoresponsive hydrogel. References: [1] Craig, J. Mater. Chem., 2011, 21, 1655-1663 [2] Weder, Chem. Mater., 2003, 15 (25), pp 4717–4724 [3] Clark, Angew. Chem. Int. Ed., 2009, 48, 5666-5669 [4] Mertz, Nature Materials, 2009, 8(9), 731-735

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Asymmetric flow-field flow fractionation of cationic nanomaterials using surface modified regenerated cellulose ultrafiltration membranes J. Ray Runyon ; Lars Nilsson Lund University, Food Technology, Engineering and Nutrition, Lund, Sweden

Asymmetric flow field-flow fractionation (FFF) has been utilized to separate an array of natural, biological and engineered complex nanomaterials ranging in size from ~2 nm to ~50 µm. Sample fractionation occurs in an open ribbon-like channel under low shear, laminar flow conditions. A fluid cross flow is applied perpendicular to the transport of the analyte through the channel yielding a hydrodynamic size based separation. At the heart of AF4 is an ultrafiltration membrane which functions to retain the analyte while allowing the cross flow fluid to pass. During AF4 fractionation analytes migrate through the channel in regions near the membrane surface. This close proximity may result in analyte-membrane interactions. Ideally these should be avoided because they can result in low sample recovery due to adsorption, irreproducible retention time, peak fronting and/or tailing, loss of resolution and incomplete characterization of the sample. Analyte-membrane interactions can be mitigated by the choice of membrane material and carrier liquid composition. The most commonly utilized membrane in AF4 applications is a regenerated cellulose (RC) ultrafiltration membrane. The use of AF4 for fractionations of cationic nanomaterials is limited due to the low isoelectric point of RC (≈3.4) and its instability at lower pHs. This presentation will present research results involving two strategies to modify the surface properties of an RC membrane for its use in AF4 fractionations of cationic nanomaterials. First, modification of an RC membrane with polyethylenimine prior to its insertion into the AF4 channel resulted in improved sample recovery, reproducibility, and molecular weight and size characterization of cationic poly-L-lysine and chitosan. Second, in-situ modification of an RC membrane with cetyltrimethylammonium bromide surfactant prevented irreversible adsorption of gold nanorods to the RC membrane surface. Batch-to-batch consistency could be evaluated from AF4 retention times and the relative amounts of gold nanorods to spheres could be estimated using dual UV-detection.

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Amphiphilic fluoroalkyl end-capped N-(1,1-dimethyl-3-oxobutyl)acrylamide – acryloylmorpholine cooligomer possessing solvatochromic and thermochromic behaviors Hideo Sawada 1; Shunsuke Izumi 2; Masato Yoshida 3 1Hirosaki University, Frontier Material Chemistry, Hirosaki, Japan; 2Hirosaki University, Hirosaki, Japan; 3Shimane University, Izumo, Japan

Amphiphilic fluoroalkyl end-capped oligomers are attractive materials, because they exhibit various unique properties such as high solubility, surface active properties, biological activities, and nanometer size-controlled self-assembled molecular aggregates which cannot be achieved by the corresponding non-fluorinated and randomly fluoroalkylated ones.[1] Here we report that amphiphilic fluoroalkyl end-capped N-(1,1-dimethyl-3-oxobutyl)acrylamide – acryloyl-morpholine cooligomer/fluorescein nanocomposites can afford brilliant yellow-colored solutions in not only protic solvents such as methanol and ethanol but also protic-like solvents such as dichloromethane and 1,2-dichloroethane, respectively. On the other hand, unexpectedly, such brilliant yellow-colored solutions provided by these fluorinated nanocomposites completely disappeared in aprotic solvents such as N,N-dimethylformamide, dimethyl sulfoxide and tetrahydrofuran. Thus, these fluorinated fluorescein nanocomposites can exhibit a coloring-decoloring behavior through solvatochromic response. In the case of fluoroalkyl end-capped N-(1,1-dimethyl-3-oxobutyl)acrylamide – acryloylmorpholine cooligomer/Rose Bengal nanocomposites, interestingly, these fluorinated cooligomeric nanocomposites-encapsulated Rose Bengal were found to exhibit the thermochromic behavior in dimethyl sulfoxide. [1] a) H. Sawada, Chem. Rev. 96 (1996) 1779; b) H. Sawada, Prog. Polym. Sci. 32 (2007) 509; c) H. Sawada, Polym. Chem. 3 (2012).

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Multilayered films for studying cell adhesion in chemically well-defined conditions Yulia Sergeeva 1; Laura Jung 2; Philippe Tropel 2; Olivier Félix 1; Viville Stéphane 2; Gero Decher 1 1Institut Chales Sadron CNRS, Strasbourg, France; 2Institut de génétique et de biologie moleculaire et cellulaire, Inserm, CNRS, Université de Strasbourg, Strasbourg, France

Due to its simplicity, robustness and versatility1 layer-by-Layer assembly is one of the most promising methods for engineering of biomaterials and carries for controlled release of therapeutics2. Since this method offers a nanoscale control over the chemical composition of films1 these materials are being used for studies of the cellular adhesion in chemically well-defined conditions3. In order to control cell-material interactions and therefore to engineer coatings for specific purposes many efforts have been made for understanding parameters influencing on cell behavior2-4. In these work we focused on influencing of film properties such as stability and wettability on adhesion of primary adult human dermal fibroblasts under cell-culture conditions. We investigate different architectures based both on synthetic polyelectrolytes such as poly(4-styrenesulfonic acid), poly(allylamine) (PAH) and poly(diallyldimethylammonium chloride) (PDDA )and natural polymers: chitosan (Chit), dextran sulfate (DexS) and alginate (Alg). The results showed higher cell viability on multilayers containing PAH such as PEI(PSS/PAH), PEI(DexS/PAH), PEI(Alg/PAH). The replacement of PAH by PDDA leads to an increase in cytotoxicity related to low stability of layers in cell environment. In contrast, films consisting of polysaccharides and hinders cell growth as depicted by the change in cell morphology. However the modification of the layer surface with arginine-glycine-aspartate (RGD) sequence dramatically increased cell attachment and spreading. In this case cell density and morphology can be controlled by adjusting surface RGD concentration. References: 1. G. Decher. Science, 1997, 277, 1232-1237 2. Z. Tang, Y. Wang, P. Podsiadlo, N. A. Kotov. Adv Mater, 2006, 18, 3203–3224 3. R. J. El-Khouri, R. Szamocki, Y. N. Sergeeva, O. Felix and G. Decher in: Functional Polymeric Ultrathin Films. R. Advincula and W. Knoll (Eds.) Wiley-VCH (2011) 4. H. Kerdjoudj, C. Boura, V. Moby, K. Montagne, P. Schaaf, J.-C. Vogel, J.-F. Stoltz, P. Menu. Adv Func Mater, 2007, 17(15), 2667–2673

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Thermoresponsive vesicles obtained by self-assembly of PNIPAM-g-PEO double hydrophilic graft copolymer for delivery of indomethacin Viktoria Michailova 1; Borislav Soklev 2; Elena Mileva 2; Evgeni Ivanov 3 1Faculty of Pharmacy, Medical University, Sofia, Bulgaria; 2Institute of Physical Chemistry, Bulgarian Academy of Sciences, Department of Interfaces and Colloids, Sofia, Bulgaria; 3Institute of Mechanics, Bulgarian Academy of Science, Open Laboratory of Experimental Mechanics, Sofia, Bulgaria

Thermoresponsive PNIPAM-g-PEO copolymer vesicles were formed and loaded with Indomethacin (IMC) in ethanol-water solutions at room temperature, below the LCST of the double hydrophilic copolymer. The copolymer is molecularly dissolved in pure ethanol and water but self-assembled into nano-sized vesicles in appropriate mixtures of them due to the cononsolvency of PNIPAM. A combination of turbidimetric, DLS, oscillatory sweep tests and TEM analysis were used to characterize the phase transition and self-association behavior of PNIPAM-g-PEO in ethanol-water solutions. It was established that individual random coil chains and mesoglobules that are normally present in a dilute aqueous solution of the copolymer (0.09 mg/ml) reorganized into spherical lamellar nanostructures even at as low as 5% (v/v) ethanol concentration. Indomethacin, a hydrophobic NSAID drug, was incorporated inside the vesicles hydrophobic wall by a nanoprecipitaion method using a slow injection protocol. Ethanol concentration was shown to have strong influence on the size, drug loading capacity and release profiles. Substantial drug loading (DLC~130%) and mean particle size around 50 nm with narrow size distribution (PDI~0.08) were obtained. IMC-loaded vesicles exhibited in vitro ethanol concentration- and temperature-dependent drug release kinetics: the process of release was faster at low ethanol concentrations and at increased temperature. These results indicate that the thermoreponsive PNIPAM-g-PEO copolymer vesicles can be considered as promising nanovectors in drug controlled release applications. Acknowledgements: Borislav Soklev acknowledges the World Federation of Scientists for PhD scholarship.

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Associative processes in thermoresponsive polymers: charge formation and the effect of additives Adriana Sturcova ; Jiri Dybal ; Larysa Starovoytova ; Jaroslav Kriz ; Alena Braunova ; Alexander Zhigunov ; Michal Pechar Institute of Macromolecular Chemistry AS CR, v. v. i., Prague, Czech Republic

In the first part, the micellization behavior of aqueous solutions of Pluronic® P85, (EO)26-(PO)39-(EO)26, has been compared with the behavior of its modification CAE-85: HOOC–CH2–CH2–CO–O–(EO)26-(PO)39-(EO)26–CO–CH2–CH2–COOH. The temperature dependent association has been followed by attenuated-total-reflectance Fourier-transform infrared (ATR FTIR) spectroscopy, by Raman spectroscopy, by the density functional theory (DFT) and by determination of pH. In CAE-85 micelles, the COOH end groups are significantly deprotonated when compared with unimers in solution. The deprotonation is a two-stage process. The first stage follows immediately after micellization and had been already predicted for low-molecular-weight surfactants. The second stage takes place only when the density of chains in micelles is sufficiently high – i.e. at temperature well above the critical micellization temperature (CMT). The second stage deprotonation had not been predicted by existing models of surfactant association. In the second part, the interactions of an additive (methyl-tert-butyl ketone, MTBK) with polyvinyl methyl ether (PVME) dissolved in deuterium oxide have been investigated. It has been shown by NMR spectroscopy that the additive has an effect on the LCST of this polymer and is probably attached to the polymer even before phase separation. ATR FTIR spectroscopy has also shown that below the transition temperature, the methyl groups of MTBK are already located in environment similar to the neat MTBK – most likely, domains rich in MTBK and attached to the polymer exist. Surface of such domains interacts with D2O molecules via the C=O groups of MTBK; two types of C=O groups exist – hydrated and neat-like. Above the transition temperature, methyl groups remain in the same environment, while the hydrated C=O groups disappear – this could be consistent with formation of MTBK domains in the interior of PVME globules.

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Polyelectrolyte nanocapsules with emulsion core Krzysztof Szczepanowicz ; Karolina Podgórna ; Marek Piotrowski ; Piotr Warszyñski Institute of Catalysis and Surface Chemistry PAS, Krakow, Poland

Nature brings numerous examples of encapsulation of various materials with size ranging from nano- to macro-scale. The most obvious examples of capsules are: a bird’s egg, a seed or in a microscopic scale, a cell along with its content. Due to their great application potential, the development of novel types of micro and nanocontainers is currently one of the main topics in the scientific research and in the last few years the major progress in the synthesis and application of various types of micro- and nanocapsules has been achieved. Depending on the final use, encapsulation technology is applied for one of the following purposes: protection, compatibility, controlled and/or targeted release. Nanoencapsulation has the high application potential in medicine since it can be used to improve the compatibility of lyophilic, poorly water-soluble or even water-insoluble active compounds with physiological fluids and can protect therapeutic molecules from the destructive influence of an external environment. Nanocapsules can be also used in specific drug delivery systems as they can penetrate the cell membrane. Moreover, they can be functionalized to achieve “intelligent targeting”, i.e. delivery to the specific cells or organs. In the presented work we were focused on the new methods of preparation of liquid core nanocapsules with polyelectrolytes shell and their biomedical application. We proposed two methods of preparation: the first one was based on the silica shell formation on the emulsion droplets and their further modification by sequential adsorption of polyelectrolytes. Second method was direct encapsulation of emulsion droplets stabilized by interfacial complex of surfactant and polyelectrolytes. Synthesized nanocapsules were further modified for targeted drug delivery. Cytotoxicity tests of capsules were done, obtained results showed that desired concentrations of nanocapsules are non-toxic to various cell lines and could be used as drug-loaded nanocarriers.

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Protein – furcellarane complexes for nanocapsule formation Ewelina Jamroz 1; Krzysztof Szczepanowicz 2; Grazyna Para 2; Barbara Jachimska 2; Piotr Warszyñski 2; Andrzej Para 1 1Department of Chemistry and Physics University of Agriculture, Krakow, Poland; 2Institute of Catalysis and Surface Chemistry PAS, Krakow, Poland

Polymer–protein interactions have been the subject of many studies over the past few years. Developing a better understanding of these systems is a matter of importance because of their use in a variety of industrial applications including pharmaceuticals, cosmetics, food industry. Recently much attention is paid to the formation of biopolimeric biodegradable nanoocapsules with permeable or semi-permeable membrane. Their use in agriculture can be advantageous as various substances, such as pesticides, contained in the microcapsules, can be released when desirable, in the required doses. That contributes to decrease of pesticides consumption and thus, to conservation soil and more ecological farming. However, finding the appropriate substrates for capsule formation and determination of parameters governing the releaser properties continues to be a challange. One of the promising methods of microencapsulation is the membrane formation by polyelectrolyte complexation by electrostatic interaction of polyelectrolytes having opposite charges. The aim of our contribution was to examine possibility of protein – polisacharide complex formation for selected proteins, as: albumin (BSA), casein, gelatin and soja-protein and oppositely charged furcellarane. Such biodegradable complexes were then used as a cores for nanoencapsulation. The electrophoretic mobility measurements as a function of furcellarane and protein concentration for various pH and ionic strength values were performed. The electrophoretic mobility data converted to zeta potential values allowed determining the isoelectric point of proteins. Basing on the values of zeta potential the optimal conditions of furcellarane – protein complex formation were determined. The negatively charged complexes were used as cores of nanocapsules, which were encapsulated by layer-by-layer adsorption of polyelectrolytes.The nanocapsules were characterized by dynamic light scattering and ζ-potential measurements. Morphology and surface of the dry nanocapsules was visualized by scanning electron microscopy

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Protein-based gels as carbon nanotubes dispersants Franco Tardani ; Camillo La Mesa La Sapienza University of Rome, Chemistry, Rome, Italy

In proper pH, ionic strength and concentration regimes, lysozyme forms gels, characterized by visco-elastic properties and peculiar supra-molecular organization modes. In incipient gelling conditions, large fibrils are formed. Nucleation of such entities is controlled by protein amount (provided it is above the phase boundary threshold), temperature, pH and aging. Protein solutions form gels upon heating; such transformation is associated to a significant increase in viscous and elastic contributions. The related transition temperature is associated to structural arrest conditions, put in evidence by dynamic light scattering. In both instances, changes at the gel transition temperature are abrupt. Protein solutions were added with single-walled carbon nanotubes before gelling. Depending on the preparation procedures and centrifugation, dilute and/or interconnected dispersions may be observed. Thereafter, gels are formed upon heating. The gels significantly differ in visco-elastic properties and macroscopic appearance, because of the formation of interconnected networks, or of a finely dispersed state. The sol-gel transitions are more or less evident, depending on experimental conditions. Efforts were made to find rational explanations to the observed features. Very presumably, gelling occurs in between the macroscopic nanotube textures, in case of pre-existing and interconnected dispersions. Their visco-elastic properties slightly depend on temperature. Conversely, gels containing tiny amounts of carbon nanotubes have nearly the same rheological behavior as the protein-based ones.

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Studying Structural Changes of Polymer Films in Real-Time using QCM-D Jennie Wikström; Ulrika Lundgren Biolin Scientific, Västra Frölunda, Sweden

Quartz Crystal Microbalance with Dissipation Monitoring (QCM-D) is a surface sensitive, real-time technique for assessment of mass and viscoelastic properties of thin films. Here we review three publications where QCM-D has been used to study the structural changes of polymer films due to stimuli such as temperature and cross-linkers. 1. Polymers grafted to a surface can adopt several different conformations. The ability to control these transitions increases the applicability of the material. In this study QCM-D was chosen specifically for the sensitivity of the technique to study changes in polymer conformation. It was possible to control the conformation of the polymers in situ and in real-time by altering temperature and grafting density and also to identify different phases in the polymer adsorption process. 2. The focus in this study was on the inflammation related protein TSG-6 and how it cross-links hyaluronan, which is abundant in the extracellular matrix. The dramatic decrease in the QCM-D signal showing energy dissipation at TSG-6 exposure made the authors determine that hyaluronan collapses into a stiffer film when interacting with TSG-6, indicating remodelling of the extracellular matrix during inflammatory processes. 3. Hydrogels have gained recent attention as functional components in biomedicine. This paper looks at hydrogels and their thermoresponsive behavior. The response behavior of temperature sensitive hydrogels of varying cross-linker molecular weight and amount was examined at different temperatures using bQCM-D. The QCM-D data provided valuable information of the mass and viscoelastic changes upon changes in temperature. 1. Zhang, G., Wu, C., Macromolecular Rapid Communications, 30 (4-5), 328-335, 2009. 2. Baranova, N. S., Nilebäck, E., Haller, F. M., Briggs, D. C., Svedhem, S., Day, A. J., Richter, R. P., J. Biol. Chem., 286 (29), 25675-25686, 2011. 3. Chirra H.D., Hilt J.Z. Langmuir, 26 (13), pp 11249–11257, 2010.

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Ultrafiltration membranes modified using the LbL technique for enhanced performances Jozef Kochan ; Le Anh Thu Nguyen ; John Erik Wong ; Thomas Melin ; Matthias Wessling RWTH Aachen University, Chemical Process Engineering, Aachen, Germany

Post-treatment surface modification is one of the different approaches to alter the surface properties of membranes. Our group focuses on the non-covalent modification of ultrafiltration (UF) membranes using the layer-by-layer (or LbL) technique [1]. The LbL technology consists of the sequential adsorption of polycations and polyanions on a charged surface and provides an environmental-friendly way to control not only the molecular architecture but also the thickness and porosity of the multilayer films deposited on the membrane. The novelty of our work lies in the adsorption of polyelectrolytes directly onto the surface of the membrane without any prior detrimental pre-treatment (such as plasma treatment) to the latter [2]. The present study reports on polyethersulfone UF membranes modified by poly(dimethyldiallyammonium chloride) and poly(sodiumstyrene sulfonate) for enhanced protein separation.The filtration performance (flux and rejection) of the coated UF membranes is characterized during filtration of proteins. It is found out that membrane separation can be efficiently tailored by judicious choice of the number of deposited layers. For instance, a two-layer modified 150 kDa UF membrane exhibits rejection similar to that of a commercially available 4 kDa UF membrane while a five-layer modified 150 kDa UF membrane hasthe same protein rejection rate as a commercially available 4 KDa UF membrane. More importantly, the LbL-modified membranes have a much enhanced permeability than the commercially available ones. Acknowledgement: Financial support from the Seventh Framework Programme under Contract No. 226791 within the NAMETECH project is gratefully acknowledged. References: [1] Decher, G. Science 277, 1232-1237 (1997). [2] Kochan, J. et al. Desalination 250(3), 1008-1010 (2010).

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Hydration behavior, functions and medical applications of soy phosphatidyl choline and diglyceride lipid compositions Marija Jankunec 1; Fredrik Tiberg 2; Johnsson Markus 2; Justas Barauskas 3 1Vilnius University Institute of Biochemistry, Vilnius, Lithuania; 2Camurus AB, Lund, Sweden; 3Malmo University, Biomedical Science, Malmo, Sweden

Lipid compositions with the ability to self-assemble into biocompatible nano- and mesostructured functional materials have many potential uses in modern medicine. By using two-component lipid systems, it is possible to tune the structure formation and related functional properties like encapsulation and extended release of small molecules and peptides, by simply varying the ratio of the lipid building blocks. This is shown in detail for the binary phosphatidyl choline (PC) and diglyceride lipid systems, currently being used in multiple development programs of novel pharmaceuticals and marketed products. A recent study on the in vitro release of disodium fluorescein from soy PC (SPC)/glycerol dioleate (GDO) non-lamellar liquid crystals (LCs) has shown that the minimum of release (lowest release rates) can be found for compositions in the two phase region between the H2 and I2 phases. Importantly, the observed release of both for small molecules and peptides from these phases are significantly more restricted compared with e.g. corresponding release rates from the highly viscous GMO V2 phase, showing the importance of phase morphology and usefulness H2 and I2 phases of the SPC/GDO system in long-acting delivery applications. Here, we have studied in detail the equilibrium aqueous phase behavior and phase structures for the two-component SPC and GDO system as a function of lipid composition by using synchrotron small angle X-ray scattering (SAXS) at the I711 and I911-4 beamlines at MAX-lab (Lund University, Sweden). The results has shown that intricate phase behavior of fully hydrated mixtures of SPC/GDO described here has not been observed before: fully hydrated SPC/GDO mixtures with increasing GDO content forms the following phase sequence: Lα→ H2→ Fd3m→ P63/mmc→ unknown “intermediate”→ Fd3m→ L2.

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Role of hydration on the physicochemical properties of native, acid hydrolyzed, and cross-linked starch Jonas Carlstedt 1; Peter Fyhr 2; Vitaly Kocherbitov 1 1Malmö University, Biomedical Science, Faculty of Health and Society, Malmö, Sweden; 2Magle AB, Kristianstad, Sweden

Starch is a biopolymer of great commercial interest and is widely used in, for example, the food, pharmaceutical, paper, and packaging industries. Generally, polymers in aqueous solutions are, to some extent, crystalline and may also display a glass transition at a certain temperature range where the polymer transforms from a brittle solid-like state into a liquid. Controlling these properties is of fundamental importance for the performance of polymeric materials in technical applications. Moreover, melting of the crystal state and the glass transition temperature are strongly dependent on the level of hydration of the polymer. In the present project, we study the changes in physicochemical properties on hydration of starch. Native potato starch is compared with acid hydrolyzed potato starch as well as cross-linked acid hydrolyzed potato starch, where the latter forms microspheres which can, for example, be used in controlled release of pharmaceuticals. By a combination of differential scanning calorimetry, water sorption calorimetry, and microscope techniques, we construct binary phase diagrams (composition vs. temperature) of the investigated system. The primary aim is thus a thorough characterization of the systems, whereas the overall goal is to propose a thermodynamic model, taking into account the changes in physical state, for the hydration of starch.

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Hydration of biofilms studied with a high-resolution QCM-D scanning technique Gesche Graf ; Vitaly Kocherbitov Malmö University, Faculty of Health and Society, Malmö, Sweden

Understanding the hydration of biofilms is crucial for investigating the functioning of living systems. In many cases biofilms (e.g. mucous surfaces or skin) are in contact with air of different humidity rather than with aqueous solutions and their functionality depends on their ability to adsorb or desorb water from the gas phase. The quartz crystal microbalance with dissipation monitoring (QCM-D) technique is a suitable way to determine rheological data of substances in addition to the mass of an adsorbate.1 Using a QCM-D humidity module the mass of water vapor that is adsorbed to a biofilm deposited on a sensor can be measured. In this way it is possible to determine the sorption isotherm of a substance which displays the amount of water taken up by a sample as a function of the water activity or relative humidity. QCM-D measurements investigating the hydration of substances are most commonly carried out using a number of saturated salt solutions that set the relative humidity to specified levels. A major disadvantage of this method is the fact that no measurements with continuously increasing and decreasing relative humidity levels can be realized making the determination of complete sorption isotherms impossible as only few points on the sorption isotherm can be measured. The aim of this work is the development of a new QCM-D scanning methodology that enables hydration measurements and determination of sorption isotherms with high resolution and accuracy. For this purpose an experimental setup is introduced that increases or decreases the relative humidity of the liquid pumped through the humidity module by continuously mixing a LiCl solution with increasing amounts of water and vice versa. The setup is tested with different substances (e.g. lysozyme or surfactants) and the results are compared with sorption isotherms obtained by sorption calorimetry.2 References (1) Dixon, M. C. J. Biomol. Tech. 2008, 19, 151-158. (2) Kocherbitov, V.; Arnebrant, T. Langmuir 2010, 26, 3918-3922.

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Understanding salt dissolution in the almost dry regime Sanna Gustavsson 1; Daniel Topgaard 1; Johan Reimer 2; Stefan Ulvenlund 1 1Lund University, Physical Chemistry, Lund, Sweden; 2Lund University, Centre for Analysis and Synthesis, Lund, Sweden

Active pharmaceutical ingredients (API) are biologically active chemicals that are used in the manufacture of pharmaceuticals. They have poor solubility in water. This means a lot of problems in the pharmaceutical industri. One of the biggest is the the poor uptake in vivo. To get around this problem many of the APIs that are manufactured today are formulated as salts with a suitable counter-ion instead of in its free form. Such salts are often found to have a higher transient solubility in biologically relevant fluids, with enhanced uptake in the body. The problem is that these API salts are very sensitive to water, and at a certain water activity a given salt will dissociate to the free form. Since about 50% of all APIs under development in the pharmaceutical industry are manufactured and formulated aΖs salts there is a great need to understand the issues concerning the interaction between salts and water and their impact on many drug projects. This study focuses on the ternary phase diagrams HX-B-H2O, where HX is an acid and B is a base (usually the API in free-form). B is a good model substance that forms a salt (HB)X with an appropriate acid HX. The salt (HB)X dissociates to its free form B in the presence of moisture. Phase behavior and molecular dynamics of these systems at low water content has been notoriously hard to characterize due to lack of efficient experimental methodologies. I this study we focus on when and how the salt (HB)X dissociates to its free form B in the presence of moisture and how it influences the physical and chemical stability of solid pharmaceutical dosage forms. We want to understand and predict the physical and chemical stability of solid pharmaceutical dosage forms at low water contents resulting from sorption of atmospheric moisture. This will be achieved by application of newly developed solid-state nuclear magnetic resonance spectroscopy methods for studies of molecular mobility and phase behavior of active pharmaceutical ingredients and common excipients at the relevant moisture contents. With the help of this new understanding one can design optimized safety profiles and maximized shelf-lifes for the formulations.

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The phase behavior of dioleoylphosphatidylcholine in water Marija Jankunec 1; Ian Harwigsson 2; Krister Thuresson 2; Markus Johnsson 2; Justas Barauskas 3; Vitaly Kocherbitov 3 1Vilnius University, Institute of Biochemistry, Vilnius, Lithuania; 2Camurus, Lund, Sweden; 3Malmo University, Faculty of Health and Society, Malmo, Sweden

The aim of this work is to construct the phase diagram of 1,2-Dioleoyl-sn-glycero-3-phosphocholine (DOPC). Depending on various molecular and ambient conditions lipids can form a variety of different liquid crystalline (LC) phases, where the lamellar phase is simplest and the most common in lipid systems. DOPC is widely used for different biological applications as the main building material of biological membranes. Lately, it plays one of the leader roles in the development of drug delivery carriers, suitable for pharmaceutical applications. There are some other applications, mostly uses of DOPC as a co–material. So, to understand which phase transitions drive lipid behavior itself, we need to study its phase behavior at low hydration levels. In order to remove all water present in commercial preparation, DOPC powder was dried under high vacuum in contact with 3 Å molecular sieves for 24 h. DOPC powder was then mechanically ground with the spatula and drying procedure was repeated for another 24 h. Karl Fischer titration revealed that in such way dried DOPC contains less than 0.05 wt. % of water. Further manipulations with dried DOPC samples were performed in a glove box in dry argon atmosphere. Thereinafter, the samples were prepared in two ways: a) by self-diffusion of water, low concentration of water (0 – 20 % wt.) were held in vapor of various saturated salts solutions at 25 °C; and b) higher water content (20 – 45 % wt.), water was added directly. The lipids specimens were allowed to equilibrate for 5 – 7 days. The phase diagram was constructed from small/wide angle X – ray diffraction (SAXD/WAXD), sorption calorimetry, and differential scanning calorimetry (DSC) data. The main results of this work are: 1. Phase diagram of DOPC – water system is constructed. 2. Dry DOPC is characterized by: Tm (temperature of melting) – 60 °C, Hm (enthalpy of melting) – 64 J/g. 3. The temperature influences in the range 0 – 15 % wt. of water these phase transitions: R3m (rhombohedral)-> Ia3d (bicontinuous cubic)-> H2 (inverted hexagonal). 4. When the DOPC/water system contains more than 15% wt. of water, Lα dominates in the phase diagram.

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Interactions of lipopolysaccharides and antennary glycine compounds in aqueous media Anna Gyurova ; Elena Mileva Institute of Physical Chemistry, Bulgarian Academy of Sciences, Department of Interfaces and Colloids, Sofia, Bulgaria

Self-assembly of star-like oligomers often results in nanostructures of unusual properties and important applications (medicine, waste water purification, etc.). Some of these oligomers form stable hydrophilic nanoplatforms in aqueous media. These platforms might serve as captive agents for endotoxins. The aim of the present study is to perform systematic investigations on the interactions of two types of lipopolysaccharides from bacteria Escherichia Coli with aqueous solutions of antennary glycine compounds. Conditions for fine tuning of lipopolysaccharide capture by the glycine platforms are outlined. The initial results are encouraging and the acquired knowledge might be applied e.g. for controlled purification of contaminated waters. Acknowledgements: The financial support of NSF of the Ministry of Education, Youth and Science (Bulgaria) by Project DO-02-256 is gratefully acknowledged.

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Manifestation of ion specificity in the behaviour of dynamic dielectric permittivity of aqueous solutions of alkali halides Farida Shagieva ; Ludmila Boinovich A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Moscow, Russian Federation

A dispersion of the refractive indices in aqueous solutions of the alkali metal halides at different salt concentrations and temperatures of the solutions was measured. A specific influence of anions on the dynamic dielectric permittivity has been revealed. A model describing the behaviour of the dynamic dielectric permittivity of solutions and the effective dynamic polarizabilities of ions in the solutions from the data on the dispersion of refractive indices has been proposed. A role of the ion’s size and the character of its interactions with the solvent in the manifestation of the specific ion effects have been discussed.

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Hydration of pig gastric mucin studied by AFM, two calorimetric techniques and QCM-D Yana Znamenskaya ; Javier Sotres ; Johan Engblom ; Thomas Arnebrant ; Vitaly Kocherbitov Malmö University, Biomedical Science, Health and Society, Malmö, Sweden

The effect of hydration on the structural and thermodynamic properties of pig gastric mucin (PGM) has been studied using atomic force microscopy (AFM), sorption calorimetry and differential scanning calorimetry (DSC) [1]. AFM indicates the presence of a dumbbell structure as well as fiber-like structure. The experimental volume of the dry dumbbell molecule obtained by AFM is 3140 ± 340 nm3. The value of the hydration enthalpy of PGM at zero water content at 25 °C is about −20 kJ/mol. Glass transition of PGM occurs at RH levels between 60 and 70%. Using DSC data, the amount of nonfreezing water was calculated to be about 0.51 g/g of PGM. The phase diagram of PGM demonstrates two regions of different Tg: dependent and independent of hydration levels. In particular, at mucin concentrations from 0 to 67 wt %, the glass transition occurs at a constant temperature of about −15 °C. At higher concentrations of mucin, Tg is increasing with increasing mucin concentrations. Also the hydration of PGM at different relative humidity levels has been studied using a quartz crystal microbalance with dissipation monitoring, QCM-D, and compared with sorption calorimetric data. QCM-D with humidity module, QHM 401®, was used to investigate the sorption isotherm and the glass transition of PGM films. A good agreement between two methods, QCM-D and sorption calorimetry, is demonstrated. The QCM-D technique requires less material (only 20-70 µg of PGM is required to obtain a sorption isotherm) and time than sorption calorimetry. Furthermore, the glass transition in thin films of biomolecules can be studied by monitoring the overtone behaviour. Our results show that, in the studied range of the film thicknesses (180-1000 nm), the experimentally measured sorption isotherm is not dependent on the thickness but the rheological properties can be dependent on the thickness of the mucin film. References: [1] Yana Znamenskaya, Javier Sotres, Johan Engblom, Thomas Arnebrant, and Vitaly Kocherbitov. J. Phys. Chem. B, 2012, DOI: 10.1021/jp212495t

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Numerical simulations of the hydrodynamics of a water droplet in paraffin oil Mickael Antoni 1; Adil Lekhlifi 1; Jalil Ouazzani 2 1MADIREL - Aix-Marseille Universite, Marseille, France; 2ARCOFLUID, Parc Innolin, Merignac, France

This work reports about numerical simulations of the unsteady hydrodynamics of a single water droplet in a continuous paraffin oil phase. The considered droplets have varying radius and are confined in a 1cm × 1cm square simulation domain. The model is two-dimensional, droplets are submitted to gravity and capillary effects are accounted for [1]. Such systems are typical examples of two phases, unsteady, free interface problems. The Navier-Stokes equation for incompressible fluids is solved with the PHOENICS Software and a volume of fluids technique. From the numerical point of view, as a droplet moves in a continuous medium, its interface ‘disappears’ upstream and is ‘created’ downstream. This simple propagation problem is still open and raises numerical precision and stability difficulties. When including capillary effects, the Navier-Stokes equation is modified by a coupling term including the water-paraffin oil interface curvature and surface tension [2]. The velocity field is shown to depend on the droplet radius, average velocity, initial position and on the working temperature. The effect of a soluble surfactant is also investigated [3]. Initially its concentration is assumed to be uniform and small enough for the surfactant to be located only on the water-paraffin oil interface. Due to the droplets motion, this distribution evolves with time. Surfactant is first transported towards the apex of the droplets and, as it is assumed to be water soluble, it is then convected inside the droplets. The main effect of this time evolution is a slowing down of the overall drainage velocity. Besides single droplet dynamics, this work also aims to propose a numerical description of flocculation and coalescence phenomena. It is conducted within the framework of the ISS/FSL/FASES project and, from this point of view, can be seen as a step in the direction of numerical studies aimed at simulating the hydrodynamics of emulsions. [1] Lekhlifi, A., et al. ,Colloids and Surfaces A, (2010), 365, 70 [2] Brackbill, et al., Comput. Phys., (1992), 100, 335 [3] Muradoglu, M., et al., J. Comp. Phys., (2008), 227, 2238

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Wetting behaviour of water on hydrophobized chemically and mechanically roughened glass and silica surfaces with defined morphologies Victoria Dutschk 1; Marina Klucereva 2 1University of Twente, Engineering of Fibrous Smart Materials, Enschede, Netherlands; 2University of Applied Sciences HTW, Dresden, Germany

It is well known that the roughness of a hydrophobic solid surface enhances its hydrophobicity. For a micro structured surface, a water drop usually stays in the Cassie-Baxter [1] state, ‘riding’ on the asperity tops of the surface. The Cassie state can be irreversibly switch to the Wenzel [2] state by pressing drop against the surface. Both surface roughness and chemical heterogeneity can be viewed as surface energy fluctuations acting as energy barriers for the three phase contact line (TPC) motion. In our previous study [3], a general bi-exponential rate law was deduced, and the wetting kinetic characteristics were related to statistical characteristics of the surface chemical heterogeneity and roughness. A step mechanism for TPC line propagation was proposed. In the present study, water contact angles were measured on differently hydrophobized glass and silica surfaces which were pre-treated using chemical and mechanical roughening to obtain defined morphologies and random structures, respectively. For hydrphobization, an amorphous fluoropolymer Teflon® AF was used [4]. To gain an insight into wetting behaviour of water on differently rough surfaces, advancing and receding contact angle as a function of modification type, time as well as drop volume were discussed. In order to explain equilibrium wetting properties in terms of roughness statistic properties and give some clues of the hysteretic behaviour, we considered the Wenzel concept. The Wenzel roughness factor was obtained from surface image analysis. References: 1 ABD Cassie, S Baxter; Trans Faraday Soc 40 (1944) 546. 2 RN Wenzel; Ind Eng Chem 28 (1936) 988. 3 R Slavchov, V Dutschk, G Heinrich, B Radoev; Coll Surf A 354 (2010) 252. 4 KG Sabbatovskiy, V Dutschk, M Nitschke, F Simon, K Grundke; Colloid Journal 66 (2004) 66 239.

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Amphiphilic molecules and disperse systems at superhydrophobic surfaces Michele Ferrari ; Libero Liggieri ; Eva Santini ; Francesca Ravera ; Eduardo Guzmán CNR, Istituto per l' Energetica e le Interfasi, Genova, Italy

Amphiphilic molecules and disperse systems, like in foams and emulsions, in contact with highly water repellent solid surfaces can play key roles in different fields in research and technology. The wettability properties of superhydrophobic (SH) surfaces showing contact angle above 150° and a very small hysteresis are exploited in many applications from self-cleaning materials to microfluidic devices. Surfactant and particles are often used to stabilize such systems but, despite the potential interest, the properties of aqueous solutions, non aqueous liquids or immiscible phases, as in foams and emulsions, have been so far rarely investigated on such solid surfaces. The SH surfaces under investigation were prepared by a mixed inorganic-organic coating on different substrates and studied in presence of different systems. Depending on the preparation SH surfaces show different aging resistance due to the composition and thickness of the hydrophobizing coating layer. The influence of surfactant adsorption can act as a switch between a Cassie-Baxter and a Wenzel regime for superhydrophobic surfaces at water-air. In addition it has been observed how the partitioning of surfactants between immiscible phases strongly affects the oil-water interface wetting properties resulting in a switch between a Wenzel and a Cassie-Baxter regime. [1] Ferrari M., Ravera F. Advances in Colloid and Interface Science, 161 (1-2) 22 (2010). [2] Krasowska M., Ferrari M., Liggieri L., Malysa K. Phys. Chem. Chem. Phys, 13, 9452., (2011) [3] Ferrari M. in Contact Angle, Wettability and Adhesion, Vol.6 Ed.K.L.Mittal, Brill-VSP 269 (2009)

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Surface quasi-two-dimensional electrolyte model applied to describe the electrolyte influence upon surface activity of dicephalic pH-responsive sugar surfactants Anna Jarzycka 1; Piotr Warszynski 2; Kazimiera A. Wilk 1 1Wroclaw University of Technology, Organic and Pharmaceutical Technology Group, Faculty of Chemistry, Wroclaw, Poland; 2Polish Academy of Sciences, J. Haber Institute of Catalysis and Surface Chemistry, Krakow, Poland

The surface quasi-two-dimensional electrolyte (STDE) model was developed by Warszyñski et al. [1] to describe quantitatively the surface tension isotherms of ionic surfactants in the presence of various electrolytes. It has been also successfully applied to characterize the adsorption of multifunctional cationic surfactants [2, 3]. In the presented work the effect of electrolyte and pH on the adsorption of dicephalic N-dodecyl-N,N-bis[(3-D-aldonylamido)propyl]amines at the air/water interface was investigated. These surfactants consist of two amide groups connected by a central tertiary amine, which may be protonated in an aqueous solution. We performed measurements of surface tension isotherms of aqueous solutions of the studied dicephalics in presence of NaCl and NaOH and applied the STDE model for evaluation of the experimental results. They showed that the adsorption of the surfactants at the air/water interface was pH- and electrolyte- dependent, since addition of NaCl and NaOH had different effect on the surface activity and critical micelle concentration values (cmc). Presence of 0.001M NaCl had a relatively minor influence on the surface tension isotherm in comparison to pure surfactant solution. On the other hand presence of 0.001M NaOH caused substantial reduction of surface tension and cmc value. The theoretical model reflected well the surface tension isotherms obtained for a broad range of surfactants concentration, confirming the theoretical predictions concerning protonation of tertiary amine, which was additionally confirmed by measurement of solution pH. 1. G. Para, E. Jarek and P. Warszyñski, Adv. Colloid Interface Sci., 122(2006), 39–55 2. J. Wêgrzyñska, G. Para, J. Chlebicki, P. Warszyñski, K. A. Wilk Langmuir 24(2008), 3171-3180. 3. R. Skrzela, G. Para, P. Warszyñski, K. A. Wilk, J. Phys. Chem. B 114(2010), 10471–10480.

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Antimicrobial dendrimers show different association mechanisms for lipid membranes with different physical properties Tania Lind 1; Zofia Urbanczyk-Lipkowska 2; Hanna Wacklin 3; Marité Cárdenas 1 1Copenhagen University, Chemistry, Copenhagen, Denmark; 2Polish Academy of Science, Organic chemistry, Warsaw, Poland; 3European Spallation Source Scandinavia, Lund, Sweden

Our modern way of living, sustained in a way by the discovery of antibiotic agents, is now threatened by bacteria becoming resistant to commonly available antibiotics. As conventional antibiotics inhibit bacterial growth mainly by acting on specific targets, the mechanism is effective but also increases the risk of resistance inducement by means of mutations and transfer of resistance genes. The answer to overcome these problems is thought to include new types of drugs, which are acting on microbes in a rather non-specific manner. Antimicrobial peptides (AMPs) were for a long time the first defense line of the innate immune response in a variety of living organisms and it is less likely that bacteria will develop a resistance mechanism against them. Novel amphiphilic nanomolecules synthesized from AMPs using a dendritic scaffold structure for increased affinity and activity, have expressed significant antifungal and antimicrobial potency even towards resistant laboratory strains. In this study, the uptake mechanism of such dendrimers has been studied on model membranes with different physical properties using complementary surface sensitive techniques including dissipation enhanced quartz crystal microbalance (QCM-D), liquid atomic force microscopy (AFM) and neutron reflection (NR). The mechanism of interaction between the dendrimers and a lipid bilayer was shown to be dependent on the lipid phase state of the bilayer. For fluid phase bilayers, the dendrimers were able to associate and integrate into the membrane finally changing the structure of the lipid bilayer into mixed lipid/dendrimer micelles. For gel-like bilayers, mainly dendrimer association to the surface of the lipid bilayer was observed, leading to bilayer stacking, probably due to the collapse of vesicles. For bilayers presenting in-plane fluid-gel phase coexistence, there seems to be a preferential interaction of the dendrimers with the fluid phase domains, since spherical aggregates were deposited into an elongated network of patches similar to the shape of the fluid phase domains. This corroborates a requirement for fluidity for dendrimer integration and bilayer solubilisation.

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CFD Simulations of dynamic profiles for growing drops Mohsen Karbaschi 1; Holger Marschall 2; Aliyar Javadi 3; Dariush Bastani 1; Dieter Bothe 2; Reinhard Miller 3 1Sharif University, Tehran, Islamic Republic of Iran; 2University of Darmstadt, Darmstadt, Germany; 3MPI KGF, Potsdam, Germany

Studying the behavior of drop profiles during their growth or harmonic perturbations for pure solvents and also solutions containing surface active compounds is of great interest for fundamental investigations in the field of dynamic liquid interfaces. In particular, the analysis of experimental data gained under highly dynamic conditions requires a separation of adsorption-desorption processes of the surfactants from effects caused by the hydrodynamics of the liquid system. In the present study the focus lies on the comparative numerical investigation of the profiles of growing drops. The Golm group applies a Volume-of-Fluid method, a surface capturing method, basing on an Eulerian grid and an additional marker function representing the phase fraction of one of the bulk phases. The Darmstadt group applies the interface-tracking method, where the interface is represented by a deformable computational grid, which is adapted according to the flow field and the surface tension forces [1]. The results gained by both methods are compared with experimental results basing on Drop Profile Analysis Tensiometer (PAT-1, SINTERFACE Technologies, Berlin, Germany) equipped with a fast video camera in order to record drop profiles in growing drop experiments at different flow rates and different pure systems, i.e. water drops in air and in hexane. The obtained drop profiles are analyzed using the standard PAT-1 software [2] to extract the mean surface tension. References: [1] K. Kissling, H. Marschall, D. Bothe, Numerical Simulation of Multicomponent Surfactant Transport on Fluid Interfaces, 6th International Berlin Workshop on Transport Phenomena with Moving Boundaries, 24th-25th November 2011, Berlin, Germany [2] M. Karbaschi, A. Javadi, D. Bastani, V.I. Kovalchuk, N.M. Kovalchuk, A.V. Makievski, E. Bonaccurso, R. Miller, Drop Profile Analysis Tensiometry under Highly Dynamic Conditions, submitted to Colloids Surfaces A, (2011) Acknowledgements: The work is supported by the DFG SPP1506.

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The role of the interfacial properties in the particle stabilized foams and solid foams Francesca Ravera ; Dominika Zabiegaj ; Eduardo Guzmán ; Eva Santini ; Michele Ferrari ; Libero Liggieri CNR-Istituto per l'Energetica e le Interfasi, Genoa, Italy

Particle stabilized foams may be used to produce microporous materials, or solid foams, characterized by low density and very high specific area. Due to these properties solid foams are utilized in a variety of different application fields such as thermal and sound insulation, molten metal filtration, hot gas cleanup, catalyst supports, CO2 absorption, components of rechargeable lithium batteries and electrolytic capacitors. An experimental study is here presented focused on the problem of tailoring of solid foams with controlled structural and chemical features produced by drying and/or sintering of liquid foams stabilized by nanosized materials. The general aim of this study is a better understanding of the relation between the interfacial properties of mixed systems containing nanoparticles (NP) at different degree of hydrophobicity and surfactants and the stability/structure of the corresponding liquid and solid foams. Single particle laden interfacial layers are then characterized by means of dynamic interfacial tension and interfacial rheology measurements as well as the stability of the corresponding particle stabilized foams. The solid foams obtained from these systems, according to specifically developed procedure, are then analyzed by SEM techniques as regards their morphology (size porosity, cell structure) and surface chemical composition. The results here presented concerning solid foams obtained by Alumina and different kind of carbonaceous NPs, presenting hydrophobic and hydrophilic character, evidence the role of the composition of the initial dispersion and in particular of the nature and concentration of the surfactant used in association to NP to stabilize the foams. References: 1. A. R. Studart et al., J. Am. Ceram. Soc., 89 (2006) 1771–1789. 2. U. T. Gonzenbach et al., J. Am. Ceram. Soc., 90 (2007) 3407–3414. 3. S. Arditty, et al.J. Colloid Interface Sci., 275 (204) 659–664. 4. E. Santini et al, Coll. Surf. A 365 (2010) 189.

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Evaporation of sessile droplets of water–based surfactant solutions: experiments and computer simulations Hezekiah Agogo 1; Ramon G. Rubio 1; Victor Starov 2; Sergey Semenov 2 1Universidad Complutense, Instituto Pluridisciplinar, Madrid, Spain; 2Loughborough University, Chemical Engineering, Loughborough, United Kingdom

Experiments on evaporation of sessile droplets of water-based solutions of surfactant SILWET L77 on top of Teflon-covered surface of a silicon wafer were performed for different values of ambient temperature, relative humidity and surfactant concentration. Four stages in the process were identified: (0) spreading, an increase in droplet contact radius while contact angle decreases and the droplet volume is almost constant, i.e. evaporation is negligible, (i) first stage of evaporation with constant droplet radius but the contact angle decreases, (ii) second stage of evaporation with constant contact angle and decreasing droplet radius, and (iii) final stage of evaporation with simultaneous reduction of both the contact angle and the droplet radius. A theoretical model for evaporation was developed to describe stages (i) and (ii). The model predicts universal curves for the time dependence of contact angle and the droplet base radius. The prediction of the model agrees reasonably well with the experimental results for pure fluid droplets on hydrophobic surfaces, as well as for droplets of surfactant solutions with concentration above CAC. However for concentrations below CAC, stage (ii) for constant contact angle was not observed. Instead, the contact angle decreased continuously as evaporation proceeds, which qualitatively can be explained by the dependence of surface tension of the liquid-air interface on the surfactant concentration. Acknowledgements: MULTIFLOW EU project FP7-ITN-2008-214919; EPSRC, UK, grant EP/D077869/1; Spanish Ministerio de Ciencia, grant FIS2009-14008-C02-01; ESA project MAP-AO-00-052; PASTA project.

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Kinetics of spreading of nanofluids Anna Trybala ; Adaora Okoye ; Sergey Semenov ; Victor Starov Loughborough University, Department of Chemical Engineering, Loughborough, United Kingdom

In the course of wetting/spreading a complex interaction of a liquid with a solid takes place. The latter processes are of enormous importance in both numerous natural and many industrial, engineering and technological processes. Nanofluids are suspensions of nanometre-sized particles in a liquid. Nanofluids are an ever growing topic in modern research due to their unique properties. The influence of nanoparticles have on the wetting properties of fluids has been the subject of increasing interest recently [1]. One of the interesting observations made is that nanofluids may enhance wetting of a nanosuspension as compared to the pure fluid [2]. However, in spit of the importance the wetting properties of nanofluids to be understood. The influence of nanoparticles on spreading of nanofluids over solid surfaces of variable wettability has been investigated experimentally, using ‘drop shape’ analysis technique. In our studies we used organic (original and modifies polystyrene latex) and inorganic (titanium, silica, carbon) nanoparticles with a range from 10 to 250 nm. We investigated kinetics of spreading of nanosuspensions over surfaces of different hydrophobicity such as silicon wafers, polypropylene, Teflon. Kinetics of spreading of nanosuspensions was investigated using a pure water and solutions of different ionic strength. Our results show that nanoparticles suspended in water has influence of spreading over difference surfaces as compared to the pure water.

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Deformation based on interfacial tension during microfiltration of oil drops on a slotted pore membrane Asmat Ullah ; Richard Holdich ; Victor Starov University of Loughborough, Chemical Engineering, Loughborough, Leicestershire, United Kingdom

The effect of interfacial tension between two fluids, on the passage and rejection of oil droplets through slotted pore membranes is investigated. A mathematical model was developed in order to predict conditions for 100% cut-off of oil droplets through the membrane as a function of permeate flux rate. Good agreement of theoretical predictions with experimental data shows that the model can be applied to the filtration of deformable droplets through slotted pore membranes. At high interfacial tension (40 mN/m) with lower flux (200 l m-2 hr-1) droplets of crude oil (27°API) were 100% rejected at droplet radius 4.3 µm using a 4 µm slotted pore membrane. At lower interfacial tension (5 mN/m), with the same flux rate, 100% rejection occurred at 10 µm droplet diameter using the same membrane. It was also found that the droplet rejection efficiency below the 100% cut-off was roughly linear with drop size, down to zero rejection at zero drop diameter. Hence, the model, coupled with this approximate correlation, can be used to predict dispersed oil drop concentration from a known feed drop size distribution.

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Synthesis, Characterization and Physico-chemical Investigation of New Piperazinium and Pyridinum Cationic Surfactants Vinay Chauhan ; Sukhprit Singh Guru Nanak Dev University, Chemistry, Amritsar, India

Cationic surfactants, is an important class of surfactant that find countless applications in household, industrial and biomedical fields. In recent years surfactants synthesized by cost effective and energy saving methodology has become priority in the field of colloid and interface science. Recently, studies related to physico-chemical interaction of surfactants and biologically active molecules have gained increased attention. Earlier we have reported the synthesis and properties of new generation imidazolium and pyridinium amphiphiles.1-4 In the continuation to our work several new cationic surfactants have been synthesized by cost effective methodology and investigated for their self aggregation properties. These new amphiphiles have been characterized by NMR, Mass and FTIR spectroscopic techniques. Further these amphiphiles have been evaluated for their thermodynamical physical parameters like critical micelle concentration (cmc), aggregation number (Nagg), surface tension at the cmc (γcmc), adsorption efficiency (pC20), effectiveness of surface tension reduction (Πcmc), maximum surface excess concentration (Ʈmax) and minimum surface area/molecule (Amin) at the air-water interface, Gibbs free energy of the micellization (ΔGmic) and Gibbs free energy of adsorption (ΔGads) by using surface tension, fluorescence and conductivity techniques. Thermal stability of these amphiphiles has also been determined by thermal gravimetric analysis under nitrogen atmosphere. The interactions of these surfactants with protein, drug and DNA have also been investigated. References: 1 A. Bhadani, S. Singh, Langmuir 25 (2009) 11703 - 11712. 2 A. Bhadani, H. Kataria, S. Singh, J. Colloid Interface Sci. 361 (2011) 33 - 41. 3 V. Chauhan, S. Singh, A. Bhadani, Colloids and Surfaces A. 395 (2012) 1- 9. 4 A. Bhadani, S. Singh, Langmuir 27 (2011) 14033 – 14044.

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Mechanics of Nerves Alfredo Gonzalez-Perez ; Lars D. Mosgaard ; Thomas Heimburg University of Copenhagen, Niels Bohr Institute, Copenhagen, Denmark

Using electrophysiological methods in combination with Atomic Force Microscopy experiments we investigate the action potential and the increase in nerve diameter associated with the signal transmission through the axon in nerves. The results were discussed in the contest of the soliton model developed by Heimburg and Jackson [1] as an alternative to the Hodgkin and Huxley model for signal propagation in nerves [2]. The experiments have been performed using the ventral cord of earthworms (Lumbricus terrestris) that were previously anesthetized for dissection and nerve extraction. The protocols used in our experiments follow the general approach in previous experiments by Tasaki et al. [3] and Kim et al. [4]. [1] T. Heimburg and A. D. Jackson, On soliton propagation in biomembranes and nerves, Proc. Natl. Acad. Sci. USA 102 (2005) 9790-9795. [2] A. L. Hodgkin and A. F. Huxley, A Quantitative Description of Membrane Current and its Application to Conduction and Excitation in Nerve, J. Physiol. 117, (1952) 500–544. [3] Iwasa, K., I. Tasaki, and R. Gibbons. 1980. Swelling of nerve fibers associated with action potentials. Science. 210 (1980) 338–339. [4] G. H. Kim, P. Kosterin, A. L. Obaid, and B. M. Salzberg, A Mechanical Spike Accompanies the Action Potential in Mammalian Nerve Terminals, Biophysical Journal Volume (2007) 3122–3129

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Interactions of parabens with self-associated structures Ana Kroflic ; Bojan Sarac ; Marija Bester-Rogac University of Ljubljana, Faculty of Chemistry and Chemical Technology, Ljubljana, Slovenia

Alkyl esters of 4-hydroxybenzoic acid (also called parabens) are still widely used in food, cosmetic, and pharmaceutical industry due to their antimicrobial activity, low toxicity, and low cost, even though controversy surrounding parabens has been mounting since late 1990s. Several studies suggested an estrogenic activity of parabens [1,2] and Darbre et al. also detected the traces of parabens in breast tumor tissue samples [3]. Notwithstanding, even today there is no proven link between parabens and breast cancer [4]. Parabens, as water-soluble antiseptics, are used in a form of sodium salts. Besides the electrical conductivity study of diluted methyl-, ethyl-, propyl-, and butyl-paraben sodium salt solutions [5] our interest is also taken in an interaction between parabens and self-assembled amphiphilic molecules, which can be treated as a model system for cellular membrane. Complex aggregation of dodecyltrimethylammonium chloride (DTAC) in aqueous sodium salicylate solutions has been already investigated by isothermal titration calorimetry (ITC), electrical conductivity, and NMR spectroscopy, which confirmed strong interactions between surfactant and salicylate ions [6]. An influence of paraben Na salts on DTAC aggregation in aqueous solution will be studied by calorimetric and electrical conductivity measurements. Micellization properties of DTAC in 0.01 M methyl- and ethyl-paraben sodium salt solutions will be investigated in temperature range between 278.15 and 328.15 K. A model function will be fitted to the titration curves and obtained thermodynamic parameters of micellization will be discussed in a sense of inclusion of parabens in the formed aggregates. [1] E. J. Routlege et al, Toxicol. Appl. Pharmacol. 1998, 153, 12−19. [2] S. Oishi, Food Chem. Toxicol. 2002, 40, 1807. [3] P. D. Darbre et al, Appl. Toxicol. 2004, 24, 5. [4] G. Shanmugam et al, Microchem. J. 2010, 96, 391. [5] A. Kroflic et al, J. Phys. Chem. B 2012, 116, 1385. [6] B. Šarac et al, Colloid Polym. Sci. 2011, 289, 1597.

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Nonequilibrium association of oppositely charged linear polyelectrolytes and surfactants in the presence of dodecyl maltoside Edit Fegyver ; Róbert Mészáros Eotvos University, Institute of Chemistry, Budapest, Hungary

It is well-known that the complexes of ionic surfactants (S) and oppositely charged polyelectrolytes (PE) can easily be kinetically arrested. One of the major reasons of the development of trapped nonequilibrium states is attributable to the formation of charge stabilized PE/S colloidal dispersions within the transparent composition range of these systems [1]. The stability of these dispersions crucially depends on the preparation protocols of the mixtures as well as on the presence of different nonionic additives such as polymers and surfactants [1-3]. In this paper the impact of dodecyl maltoside (C12G2) on the aqueous mixtures of sodium polystyrene sulfonate – hexadecyltrimethylammonium bromide and poly(diallyl-dimethylammonium chloride) – sodium dodecyl sulfate systems have been investigated using dynamic light scattering, electrophoretic mobility, turbidity and steady-state fluorescence measurements. The application of the so-called slow-mixing protocol leads to precipitation in a wide composition range both in the presence and absence of C12G2. In contrast, if the rapid homogenization of the systems is ensured via the stopped-flow mixing protocol, then the mixtures could be trapped in the charge stabilized colloidal dispersion state in a large concentration range. This kinetically stable composition region increases further via the addition of C12G2. The electrophoretic mobility and DLS measurements reveals that the mean size and charge of the formed PE/S nanoparticles are considerably dependent on the concentration of C12G2. These results can be rationalized by taking into account the synergistic binding of the uncharged and charged surfactant molecules to the polyelectrolyte as well as the effect of the local inhomogeneities during the homogenization of the systems. References: (1) Pojják K., Bertalanits E., Mészáros R., Langmuir 2011, 27, 9139. (2) Mezei A., Mészáros R., Soft Matter 2008, 4, 586. (3) Pojják K., Mészáros R., Langmuir 2011, 27, 14797.

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Controlled colloid pattern assembly and attachment strength in evaporating droplets Veronica L. Morales 1; Jean-Yves Parlange 2; Mingming Wu 3; Wei Zhang 4; M. Ekrem Çakmak 5; Anthony E. Salvucci 2; Wenjing Sang 2; Tammo S. Steenhuis 2 1SIMBIOS Centre, University of Abertay Dundee, Bell Street, United Kingdom; 2Cornell University, Biological and Environmental Engineering, Ithaca, New York, United States; 3Cornell University, Chemical and Biomolecular Engineering, Ithaca, New York, United States; 4Michigan State Univesity, Crop and Soil Sciences, East Lansing, Michigan, United States; 5Çukurova University, Environmental Engineering, Adana, Turkey

This study demonstrates that manipulation of the pattern assembly and attachment strength of colloids in an evaporating sessile droplet resting on a pristine poly(methyl methacrylate) (PMMA) substrate can be achieved by altering the aqueous solution’s surface tension. For the range of surface tensions (ST) investigated (72-39 mN m-1), three distinct deposition patterns were produced: amorphous stains (ST 72-63 mN m-1), coffee ring stains (ST 53-45 mN m-1), and concentric rings (ST 45-39mN m-1). Respectively, the attachment strength of the colloid stains decreased, as determined from flow displacement tests with an applied shear stress of 8.2 kg m-2. Characteristic drying regimes associated with the three unique pattern formations are attributed to abrupt transitions of contact line dynamics during evaporation. The first transition from slipping- to pinned-contact line was found to be a direct result of the competition between mechanical instability of the droplet and the friction generated by pinned colloids at the contact line. The second transition from pinned- to recurrent stick and slip-contact line was found to be a direct result of recurrent liquid film rupturing from evaporation-intensified surfactant concentration. The range of attachment forces observed between the colloids and the solid substrate were well captured by extended DLVO interactions for van der Waals attraction, electric double layer repulsion and micelle-protrusion repulsion.

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Development of novel drug delivery system by tunable plasma lipoprotein Hideaki Oshima 1; Retsu Taniguchi 1; Amika Yoshida 1; Yoichiro Yoshikawa 1; Ken-ichiro Suzuki 2; Ken Takeda 1 1Tokyo University of Science, Department of Hygiene Chemistry, Chiba, Japan; 2Tokyo University of Science, Institute of Science & Technology, Chiba, Japan

Brain development and maintenance proceeds on the basis of cerebral sustenance transportation across the blood brain barrier (BBB), disorders of which can induce neurodegenerative diseases, leading to more frequently occurring disorders and increased treatment expenses. Recent scientific advances highlight that knowledge of this transportation will lead to the development of tailor-made theranostic strategies. Biotechnological tools such as biocompatible nanoparticles have promising potential in this context, however, information about their consequences in the brain is largely unknown. The present study develops novel cerebral sustenance nanoparticles in the form of tunable plasma lipoproteins (TPLs). Tunable components are the nanoparticles, phospholipids, and apolipoproteins. The synthesis is based on self-assembly processes. The hydrophobic gold nanoparticles (AuNPs) adsorb the phosphatidylcholines (PCs), which additionally increases their dispersion rate in saline. PC-coated AuNPs were labeled with the cell tracker CM-DiI to trace the TPL via fluorescence microscopy. The labeled PC-coated AuNPs were modified with apolipoprotein-B100, which are common components such as low-density lipoproteins. Subsequently, we demonstrate TPL passage across the BBB as well as delivery to glial precursor cells. The adjustability of the tunable plasma lipoproteins enables their use in theranostic applications against neurodegenerative diseases.

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Studies of nanoaggregates formed by 1,4-dihydropyridine amphiphiles possessing antiradical activity Oksana Petricenko 1; Baiba Skrivele 2; Karlis Pajuste 2; Dainis Kaldre 2; Brigita Cekavicus 2; Mara Plotniece 2; Velta Ose 3; Martins Rucins 2; Marina Gosteva 2; Arkadij Sobolev 2; Aiva Plotniece 2 1University of Latvia, Riga, Latvia; 2Latvian Institute of Organic Synthesis, Riga, Latvia; 3Latvian Biomedical Research and Study Centre, Riga, Latvia

1,4-Dihydropyridine (1,4-DHP) amphiphiles possess self-assembling properties such as formation of liposomes. These compounds are very efficient in delivery of plasmid DNA (pDNA) into several cell lines in vitro. Compound 1 (1,1'-[(3,5-didodecyloxycarbonyl-4-phenyl-1,4-dihydropyridine-2,6-diyl)dimethylen]-bispyridinium dibromide) was more active in this respect than DOTAP and PEI 25, well known commercial gene delivery agents [1,2]. The aim of this work is characterisation of nanoaggregates formed by 1,4-DHP amphiphiles as putative delivery systems as well as studies of biological properties of structural analogues of the compound 1. Characterisation of formed nanoaggregates in water was achieved by atomic force microscopy (AFM), transmission electron microscopy (TEM) and the hydrodynamic diameter of particles was determined by the dynamic light scattering (DLS) method. Generally, it would be concluded that the structure of the cationic head-group of 1,4-DHP amphiphiles affects the size of nanoparticles formed of tested compounds. Further studies of the effect of sample concentration, sonication time and storage conditions on the size and morphology of formed nanoparticles are currently underway in our laboratory and will be discussed. Presence of antiradical activity (ARA) and antioxidant activity (AOA) is believed to be an advantage of the carrier since it can prevent DNA from chemical degradation induced by free radical oxidation upon complexation or storage of the complexes. According to our results it can be concluded that the presence of cationic head-group of 1,4-DHP amphiphiles is the crucial for expression of radical scavenging activity among this kind of compounds. Acknowledgements: Studies were supported by the ESF project “Design of new pharmacomodulators and studies of their nanoassociates as transport forms” (No.2009/0197/1DP/1.1.1.2.0/09/APIA/VIAA/014) and the grant Nr 09.1566 from Latvian Council of Science. References: [1] Z. Hyvönen, A. Plotniece et al, Biochim. Biophys. Acta, 1509 (2000) 451. [2] Z. Hyvönen, S. Rönkkö et al, J. Contr. Release, 99 (2004) 177.

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Thermodynamics of micellization of ionic and non-ionic surfactants from DSC measurements Bojan Sarac ; Jurij Lah ; Marija Bester Rogaè Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana, Slovenia

Since it has become evident that folding of proteins or nucleic acid molecules, binding of ligands to macromolecules, and many other biological processes are in principal reversible, thermodynamically driven processes, the development of highly sensitive calorimetric techniques, such as isothermal titration calorimetry (ITC) and differential scanning calorimetry (DSC), have risen steeply [1,2,3 ]. The key role in the above-mentioned processes has a hydrophobic effect [4], but due to the structural complexity of biological macromolecules, thermodynamic characterization of the hydrophobic effect is often hindered. Over the years of dealing with surfactants, ITC has become indisputably more important technique than DSC [5]. From the enthalpograms obtained by the ITC, it is relatively easy to determine the enthalpy of micellization of a surfactant. Due to a relatively high concentration of a surfactant in the syringe we often do not encounter problems such as low strenght of the signal, high noise ratio or drift of a baseline. On the contrary, DSC frequently encounters all the above problems, which, in combination with complicated thermograms, aggravate a determination of thermodynamic parameters in straighforward manner. Confronted with all depicted facts, the main question arises: is it possible to get full thermodynamic description of micellization by DSC alone, by the use of simple model equation? In this work we will try to address this question and present the advantages and disadvantages of using DSC for thermodynamic characterization of micellization of surfactants. For this purpose we have nonionic surfactant C8E5 in water as solvent and cationic surfactant DTAC in high salt content, namely 0,1 M NaCl. [1] P. L. Privalov; V.V. Plotnikov; V.V. Filimonov J. Chem. Thermodyn. 1975, 7, 41. [2] P. L. Privalov Pure Appl. Chem. 1980, 52, 479. [3] G. Privalov et al; P. L. Privalov Anal. Biochem. 1995, 232, 79. [4] C. Tanford The Hydrophobic Effect: Formation of Micelles and Biological Membranes, 2nd ed., Wiley-Interscience Pub., 1980. [5] J. Lah et al J. Phys. Chem. B 2006, 110, 23279.

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Surface activity of saponin from Quillaja bark at the water/air and water/oil interfaces Kamil Wojciechowski ; Joanna Lewandowska ; Aleksandra Kezwon Warsaw University of Technology, Warsaw, Poland

Surface activity of Quillaja bark saponin from Sigma (QBS) was studied using dynamic interfacial tension at three fluid/fluid interfaces with the polarity of the non-aqueous phase increasing in the order: air/water, tetradecane/water and olive oil/water. In each case saponin adsorbs from the same aqueous phase, but the kinetics of this process is to some extent dependent on the nature and polarity of the contacting non-aqueous phase. Surface rheological characteristics of QBS at the olive-oil/water interface confirms formation of elastic surface layers. Also the interfacial tension isotherms display marked differences depending on the polarity of the non-aqueous phase. At the olive oil/water interface the adsorbed layers are so thick and rigid, that the drops immersed in the oil phase wrinkle upon fast compression, a phenomenon observed previously at the air/water interface for QBS obtained from a different supplier. The surface behaviour of two Quillaja bark saponins from different suppliers will be compared.

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Self-assembled nanostructures of fully hydrated monoelaidin-elaidic acid and monoelaidin-oleic acid systems Anan Yaghmur 1; Barbara Sartori 2; Michael Rappolt 2 1University of Copenhagen, Department of Pharmacy, School of Pharmaceutical Sciences, Faculty of Health and Medical Sciences, Copenhagen, Denmark; 2Austrian Academy of Sciences,, Institute of Biophysics and Nanosystems Research (IBN), Graz, Austria

Trans fatty acids (TFAs) are produced during the partial hydrogenation of unsaturated oils in food industry. One of the key issues for the formation of healthy products is significantly decreasing the total industrial TFAs content, since the dietary trans fat level dictates the quantity of incorporated unhealthy fatty acids into the biological cell membranes. Therefore, the formulation of new food products with low or zero TFAs content is gaining increasing attention. At the molecular level, the underlying mechanisms of how the incorporation of TFAs into lipid membranes induces harmful effects are still not well established. Our present contribution is focusing on understanding the impact of loading oleic acid (OA, C18:1c9) and its congener elaidic acid (EA, C18:1t9) on ME self-assembled nanostructures under full hydration conditions. Firstly, the impact on the structure upon the partial substitution of ME (EA-containing lipid) by monoolein (MO, OA-containing lipid) is investigated under full hydration conditions. Secondly, the structural characterization of different self-assembled nanostructures of the ternary ME/EA/water and ME/OA/water systems at different ME/EA and ME/OA weight ratios is presented. In these investigations, the crucial role of the lipid composition and experimental temperature on modulating the lamellar-nonlamellar transition in these ternary model membranes is discussed. It is clear that the fully hydrated ME/EA and ME/OA systems exhibit a rich and a complex polymorphism of self-assembled inverted-type liquid crystalline phases with long-range periodicities and variable lattice parameters [1]. The formed liquid crystalline phases (LCs) include Lα V2 phases of the symmetry Pn3m and Im3m, H2 phase, and discontinuous cubic phase of the symmetry Fd3m. The crucial role of the temperature-dependence of these fully hydrated ME systems in modulating the nanostructures in the presence of EA or its congener OA is reported. We highlight also the main differences between OA and EA. References: [1] A. Yaghmur, B. Sartori, M. Rappolt (manuscript in preparation).

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A combined theoretical and experimental study of Surface Modified Anatase Colloidal Nanoparticles Tatjana D. Savic 1; Ivana A. Jankovic 1; Zoran V. Saponjic 1; Mirjana I. Comor 1; Dusan Z. Veljkovic 2; Snezana D. Zaric 2; Jovan M. Nedeljkovic 1 1Vinca Institute of Nuclear Sciences, University of Belgrade, Belgrade, Serbia; 2Department of Chemistry, University of Belgrade, Belgrade, Serbia

Surface modification of nanocrystalline colloidal TiO2 particles (45 Å) with catecholate-type ligands consisting of extended aromatic ring system, that is, 2, 3-dihydroxynaphthalene and anthrarobin was found to alter optical properties of nanoparticles similar to catechol. The formation of the inner-sphere charge-transfer (CT) complexes results in a red shift of the semiconductor absorption compared to unmodified nanocrystallites and the reduction of the band gap upon the increase of the electron delocalization on the inclusion of additional rings. According to Job’s method of continuous variation, for chosen enediol modifiers, binding was found to be through bidentate binuclear (bridging, catecholate type) complexes leading to restoration of six-coordinated octahedral geometry of surface Ti atoms. From the Benesi-Hildebrand plot, the stability constants in methanol/water = 90/10 solutions at pH 2 of the order 103 M-1 have been determined. The binding structures were investigated by using FTIR spectroscopy. Also quantum chemical calculations on model systems using density functional theory (DFT) were performed to obtain vibrational frequencies of charge transfer complexes, and the calculated values were compared with the experimental data. DFT calculations of Ti2OL(OH)4 (bridging) vibrational frequences show better agreement with experimental data in comparison to TiL(OH)2 (chelating) frequencies. It is obvious that the extension of the aromatic ring system in modifier molecules opens up the possibility for fine-tuning of the electronic properties of TiO2 nanoparticles.

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Effect of linear nonionic polymer additives on the association between poly(diallyldimethylammonium chloride) and sodium dodecyl sulfate Edit Fegyer ; Katalin Pojják ; Róbert Mészáros Eotvos University, Institute of Chemistry, Budapest, Hungary

In recent work, it has been shown that the addition of large molecular mass poly(ethyleneoxide) (PEO) or poly(vinylpyrrolidone) (PVP) may affect considerably the properties of branched poly(ethyleneimine) (PEI)/sodium dodecyl sulfate (SDS) aqueous mixtures [1-2]. This finding is attributable to the adsorption of the nonionic additives on the surface of PEI/SDS nanoparticles which -depending on the concentration of the uncharged polymer- can either enhance or reduce the aggregation of these particles. In the present study the impact of PEO and PVP on the nonequilibrium association between poly(diallyldimethylammonium chloride) (PDAC) and SDS has been investigated in aqueous medium using dynamic light scattering (DLS), electrophoretic mobility, turbidity and coagulation kinetics measurements. The DLS and mobility measurements indicate that the investigated PEO and PVP samples adsorb on the surface of PDAC/SDS nanoparticles formed in the presence of surfactant excess. However, the extent of adsorption is significantly lower compared to the colloidal dispersions of PEI/SDS nanoparticles. The aggregation rate of the PDAC/SDS nanoparticles reveals a unique dependence on the polymer additive concentration. At low polymer concentrations, the coagulation of the nanoparticles is enhanced. By further increasing the amount of uncharged polymer, the aggregation rate of the PDAC/SDS nanoparticles first decreases and then starts to increase again. In sharp contrast to the PEI/SDS system, steric stabilization of the PDAC/SDS colloidal dispersions cannot be achieved even at very high concentrations of PEO or PVP. The study indicates that the effect of nonionic polymer additives significantly depends on the nature of the applied uncharged polymers as well as References: (1) Pojják K., Mészáros R., Langmuir 2009, 25, 13336. (2) Pojják K., Mészáros R., J. Col. Int. Sci. 2011, 355, 410.

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Role of water transfer mechanisms in the struture of water in paraffin oil emulsions Mickael Antoni 1; Murielle Schmitt 1; Stéphanie Limage 1; Sébastien Vincent-Bonnieu 2 1MADIREL - Univ. Paul Cezanne, Marseille, France; 2ESA - ESTEC, Physical Science Unit, Noordwijk, Netherlands

Recent investigations reported about silicone oxide dispersions with different amounts of CTAB. The aim of these studies was the understanding of the role of surfactant modified nanoparticles on the overall stability of diluted water in paraffin oil emulsions and to report about a transition in the shape of the water droplets that from spherical can become strongly deformed [1-3]. This work proposes to focus on the modifications occurring in the previous emulsions when adding SPAN80. This surfactant is soluble in paraffin oil. This study is motivated by the fact that the aforementioned deformed droplets behave as stiff objects due to the existence of silicon oxide microstructures within them. But the precise balance of the role of these bulk microstructures and the one of interfaces is still in discussion. Bulk properties are indeed not sufficient to fully explain the deformation of the droplets. In this context, the addition of SPAN80 could be one way to probe the actual contribution of water paraffin oil interfaces. When increasing the SPAN80 concentration, the typical size of the droplets decreases. As the emulsification procedure is the same for all our experiments, this is simply a consequence of the reduced surface tension. The unexpected effect here is the recovery of spherically shaped droplets for increasing SPAN80 concentrations with a transition threshold close to 0.04 g/L. Moreover, in the presence of SPAN80, the continuous paraffin oil phase of the emulsions is opacifying with time. This indicates the appearance of micron-sized objects. Microscopy observations demonstrate that these latter are due to the transfer of significant amounts of water from the droplets into the paraffin oil phase. The kinetics of this migration mechanism is shown to depend on the SPAN80 concentration. [1] Schmitt-Rozières M., et al., Langmuir, 25, (2009), 4266 [2] Limage, S., et al., Langmuir, 26, (2010), 16754 [3] Ravera, F. et al., Colloids Surf. A, 323, (2008), 99

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Quarternized-poly(N-vinylimidazole)/montmorillonite nanocomposite: synthesis, characterization and electrokinetic properties H. Ibrahim Unal 1; Ozlem Erol 1; O. Yunus Gumus 2 1Gazi University, Chemistry Department, Ankara, Turkey; 2Nevsehir University, Chemistry Department, Nevsehir, Turkey

Nanocomposites are a combination of two or more phases containing different compositions or structures, where at least one of the phases is in the nanoscale range. Clays are used as additives since they are composed of layered silicates that can intercalate organic molecules. Compatibility between the silicate clay layers and the polymers is therefore achieved by ion exchange reactions. While the interlayer cations of silicate clays are usually Na+, K+, or Ca2+ exchange reactions with an organic cation increases the organophilicity of the clay layer surface. This lowers the surface energy and improves wetting with the polymer matrix. Poly(N-vinylimidazole) (PVI) is a weak basic polyelectrolyte and has been already used as a model polyelectrolyte to study adsorption properties on various minerals in the literature [1]. In this study, it was aimed to bring together the superior properties of montmorillonite (MMT) clay and PVI. For this purpose, first PVI was synthesized and then quarternized (Q-PVI) to better interact with MMT. Further, a new nanocomposite was prepared from Q-PVI and MMT by solution intercalation method. The nanocomposite (Q-PVI/MMT) prepared were characterized by FTIR, SEM, TGA, XRD, and elemental analysis techniques. Their conductivities, dielectric constants, and densities were also determined. Aqueous dispersions of MMT and Q-PVI/MMT were prepared and the effects of pH, temperature, various surfactants (anionic, cationic, and nonionic) and electrolytes (mono, di, trivalent, anionic, and cationic) on their zeta-potentials were determined by electrokinetic experiments. It was observed that Q-PVI/MMT had positive surface charge in the wide range of pH and showed isoelectric point (IEP) whereas MMT had negative surface charge in the whole range of pH with exhibiting no IEP. Acknowledgements: The Gazi University Research Fund (FEF 05/2010-01) and COST CM1101 Action. [1] N. Tekin, E. Kadinci, O. Demirbas, M. Alkan, A. Kara, J. Colloid Interf. Sci. 2006, 296, 472–479.

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A simple copolymer system to linearly tune size and phase transition properties of non-NIPAM based microgels Bastian Wedel ; Michael Zeiser ; Oliver Schipper ; Thomas Hellweg Bielefeld University, Physikalische und Biophysikalische Chemie, Bielefeld, Germany

Temperature responsive microgels undergo a volume phase transition (VPT) at a certain temperature (VPTT). It is this specific property that makes such kind of structure interesting for various applications, such as sensors, nanoactuators or as drug delivery systems. The most studied thermoresponsive polymer is poly(N-isopropylacrylamide) (PNIPAM) with a VPTT of 32 °C. It is a very established technique to <tune the phase transition via copolymerization of NIPAM with other monomers.[1,2] In this study, we present a series of copolymer microgels based on two temperature responsive monomers. The used monomers are N-n-propylacrylamide (NNPAM) and N-isopropylmethacrylamide (NIPMAM) with VPTTs of the homopolymer microgels of 22 °C and 43 °C respectively. We analyzed the dependence of the composition on the VPT and the particle size with turbidity measurements, photon correlation spectroscopy and scanning electron microscopy. Moreover, the influence of the surfactant concentration used during the synthesis was investigated. We found out, that the VPTT is linearly correlated with the nominal composition of the copolymer microgels. The VPTT range of the copolymers is limited by the homopolymer systems. Furthermore, the width of the VPT and the particle size is influenced by the amount of surfactant, the composition and the chemical structure of the monomers. According to all results, we present a simple system which enables a linearly control of VPTT and particle size for thermoresponsive microgels. Literature: [1] Snowden, M. J.; Chowdhry, B. Z.; Vincent, B.; Morris, G. E.: J. Chem. Soc., Faraday Trans. 1996, 92, 5013–5016. [2] Hertle, Y.; Zeiser, M.; Hasenöhrl, C.; Busch, P.; Hellweg, T.: Colloid Polym Sci. 2010, 288, 1047-1059.

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Phase behavior of linearly thermoresponsive core-shell microgels Michael Zeiser ; Ines Freudensprung ; Thomas Hellweg Bielefeld University, Physikalische und Biophysikalische Chemie, Bielefeld, Germany

Over the last decade smart microgels have been increasingly recognized as potential building blocks for photonic materials, catalytic carriers and sensors[1]. We recently developed a system-class of non (N-isopropylacrylamide)-based core-shell microgels which are able to exhibit a linear thermoresponse in a temperature range between 25°C and 40°C. In general, this class comprises different thermoresponsive polymers in the core and shell[2]. It is the chosen combination of specific materials with largely different phase transition temperatures in the core and shell, that gives the particles their unique responsive behavior. Our contribution demonstrates how core particles with different characteristics (elasticity, phase behavior, hydrophobicity) influence overall core-shell properties. Photon-correlation spectroscopy and turbidity measurements allowed us to study the phase behavior of the obtained microgels. We show that the mechanical properties and the phase behavior of the core particles are the key parameters that influence the linear thermoresponse. Additionally we discuss the role of synthesis conditions on the final systems. Besides equilibrium phenomena we determined the kinetics of the corresponding phase transitions using stopped-flow T-jump and turbidity measurements. Especially the fast response makes these particles promising candidates for novel nanoactuator and sensor applications. Literature: [1] A. Fernandez-Nieves, H. Wyss, J. Mattsson and D. Weitz Microgel Suspensions Wiley VCH, Weinheim, Germany, 2011 [2] I. Berndt and W. Richtering Macromolecules 2003, 36, 8780

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Formulation of A Nano-additive Inkjet Ink for Fabric Functionalization Jie Zhao ; Marijn Warmoeskerken ; Dutschk Victoria University of Twente, Faculty of Engineering Technology, Enschede, Netherlands

Inkjet printing technique can be used as a novel approach with high efficiency, high quality, low cost and low pollution to deposit nano-additives on fabric surfaces. Due to the excellent photo-catalytic activities making TiO2 nanoparticles applicable as self-cleaning and anti-bacterial agents, as well as for UV protection and environmental purification, a great potential for multi-functionalization of fabrics by TiO2 nanoparticles is considered [1]. In order to improve the durability of nanoparticles at a fabric surface, the surface of commercial TiO2 nanoparticles was modified by 3-aminopropyltrimethoxysilane (APTMS) by an aqueous process in our previous study [2]. In this study, the zeta-potential and hydrodynamic diameter of differently modified TiO2 nanoparticles in aqueous ink solution was measured by Dynamic Light Scattering (DLS) zetasizer as a function of molecular weight and concentration of polyvinylpyrrolidone (PVP). The results show PVP can act as a good dispersant for particles in the ink solution. The hydrodynamic diameters of TiO2 nanoparticles decrease with an increase in the molecular weight and concentration of PVP, which is caused by its adsorption behavior and steric hindrance [3]. Moreover, due to the existence of –NH2 functional groups at modified TiO2 nanoparticle surface, PVP exhibits stronger adsorption and larger shift in isoelectric point on modified nanoparticles than those on unmodified ones. The drop/bubble Profile Analysis Tensionmetry (PAT) is used to determine static and dynamic properties of liquid-gas interfacial system in the presence of TiO2 nanoparticles and PVP. The dynamic dilational rheology of the ink solution is measured with harmonic surface oscillation in the frequency range between 0.01 Hz and 1 Hz. The visco-elasticity modulus of the ink solution is investigated at different molecular weights and concentrations of PVP. The results indicate the aggregation of TiO2 nanoparticles lead to a significant increase of visco-elasticity modulus.

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Polyelectrolyte-surfactant interaction in Hyaluronan-CTAB system around critical aggregation concentration Michaela Šejnohová ; Filip Mravec ; Tereza Halasova ; Miloslav Pekaø Brno University of Technology, Faculty of chemistry, Brno, Czech Republic

Hyaluronan as biocompatible and biodegradable polymer is suitable molecule for preparation of new drug delivery carriers and if its aggregates containing cetyltrimethylammonium bromide (CTAB) are not directly potential new drug delivery systems, so are helpful model systems for them at all events. Formation of aggregates in this system was confirmed by previous studies of Thalberg et al. [1-3]. This work was focused on detailed aggregation behaviour of CTAB in its concentrations tightly around critical aggregation concentration which occurs in a presence of Hyaluronan. The molecular weight of hyaluronan was 300 kDa and its concentration was set to 10 mg/L. Concentration of hyaluronan was unchanged. Influence of fluorescence probe pyrene concentration and sample preparation were also studied. First experiments showed that phase separation occurred in system approximately at ten times lower concentration than critical micellar concentration for aqueous solution CTAB without hyaluronan. But further examination showed existence of short concentration range between CAC and phase separation in which Hyaluronan-CTAB aggregates are stabile in solution. This range and aggregates belonging to it are interesting for further examination as potential drug delivery carriers for hydrophobic species.

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Shear-induced structure formation in a mixture of hydroxypropylmethyl cellulose and sodium dodecyl sulfate Jaroslav Katona 1; Verica Sovilj 1; Lidija Petrovic 2 1Faculty of Technology, Applied and Engineering Chemistry, Novi Sad, Serbia; 2Faculty of Technology, Biotechnology and Pharmaceutical Engineering, Novi Sad, Serbia

Interaction between polymers and surfactants is of tremendous, both scientific and industrial importance. A number of colloidal systems consist of a mixture of polymers and surfactants, and thus are to a large extent determined by the interaction. In this work, influence of shear rate on interaction between hydroxypropylmethyl cellulose (HPMC), a nonionic amphiphilic cellulose ether, and sodium dodecylsulfate (SDS), an anionic surfactant, was investigated. Concentrations of both HPMC and SDS (0.00-2.00% wt.) were varied, 0.5-1.0% wt. and 0.00-2.00% wt. respectively. In a lower shear rate range, viscosity curves of HPMC-SDS systems showed typical shear thinning behavior. The rheological measurements allowed determination of characteristic HPMC-SDS interaction concentrations, i.e. the critical association concentration (cac) and the polymer saturation concentration (psp). On further increase in shear rate, the shear thinning behavior was disrupted by an increase in viscosity accompanied with a development of the first normal stress difference (N1), indicating shear-induced structure formation in the system. The increase in viscosity takes place at a characteristic shear rate which depends on HPMC as well as on SDS concentration in the system. Shear induced structure formation occurs in a specific SDS concentration range (for a given HPMC concentration), where below or above this range no increase in viscosity was observed and the viscosity curves are again shear thinning.

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Tensiometric study of surfactant micellization induced by hyaluronan Jitka Krouská ; Miloslav Pekaø Brno University of Technology, Faculty of Chemistry, Centre for Materials Research, Brno, Czech Republic

The motivation for the present work was to prove interactions between a natural negatively charged polysaccharide hyaluronan and two cationic surfactants tetradecyltrimethylammonium bromide (TTAB) and hexadecyltrimethylammonium bromide (CTAB) in aqueous solutions. Recently, the research based on polyelectrolyte-surfactant interactions is worldwide. In the case of hyaluronan, mostly the phase separation of hyaluronan-cationic surfactant was studied and relatively little is known on hyaluronan effects on micellization. Knowledge of surfactant aggregation at the presence of hyaluronan is essential for development of hyaluronan-surfactant systems for targeted delivery. These interactions were studied by surface tension method at room temperature. The stock solution of hyaluronan (molecular weight 130 and 1750 kDa) was stirred overnight before measurement, the surfactant solutions were stirred for 2 hours. Surface tension of samples with constant hyaluronan concentration and increasing surfactant concentration was measured using a Du Noüy ring method to obtain a plot of surface tension versus surfactant concentration. The critical aggregation and micelle concentration were determined as a break point on the curve in this plot. It was proved that added hyaluronan causes aggregation process at lower surfactant concentration when compared to pure surfactant. Moreover, surface tension values of samples with hyaluronan showed no decreasing trend with increasing surfactant concentration as is known for pure surfactants because hyaluronan chains interact with surfactant monomers and micelles in bulk and do not allow them to adsorb on the surface. This work was supported by the COST action CM1101, project No. LD12068 and project No. CZ.1.05/2.1.00/01.0012 from ERDF.

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Binding of hyaluronan to CTAB micelles - a turbidimetric study Miloslav Pekaø Brno University of Technology, Materials Research Centre, Brno, Czech Republic

Hyaluronan is a highly hydrophilic biopolymer found primarily in the extracellular matrix of all higher organisms, especially in connective tissues, synovial fluid, and eye vitreous and is produced by certain strains of bacteria. Its basic repeating unit, composed from β-(1→4)-D-glucuronic acid β-(1→3)-N-acetyl-D-glucosamine disaccharide, gives it polyelectrolytic properties with negative charge and sodium counterions. Due to its biocompatibility and physiological functions hyaluronan is among ideal candidates for applications in systems of controlled release or targeted delivery. Due to its hydrophilic character hyaluronan cannot be directly used to carry nonpolar active substances. Formation of complexes between hyaluronan and positively charged micelles can be a solution to this problem. This contribution reports on the results of turbidimetric study of interactions between hyaluronan and cetyl trimethylammonium bromide (CATB) micelles. Hyaluronan of molecular weight about 1 600 kg/mol was dissolved in water (0.01% w/v) and this solution was used to titrate micellar solutions of CTAB of two different concentrations ¨C 3 and 10 mmol/l. Turbidity of titrated solutions was measured using Varian Cary 50 spectrophotometer equipped with fiber optic probe with 1 cm optical path length at 420 nm. Blank corrections were made with hyaluronan free systems. Charge ratio surfactant/hyaluronan was changed during the titration within the range 5000 - 4. Systems with lower surfactant concentrations remained visibly clear and no turbidity was measured. Turbidity in systems with higher surfactant concentration progressively increased from the very beginning with three distinguishable approximately linear parts corresponding to clear, opalescent, and cloudy systems. Data were used to construct phase portrait of hyaluronan-CTAB micelles system. This work was supported by the COST action CM1101, project No. LD12068 and project No. CZ.1.05/2.1.00/01.0012 from ERDF.

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Enzymatic synthesis of conducting polymers Almira Ramanaviciene 1; Vida Krikstolaityte 2; Oztekin Yasemin 2; Natalija German 1; Asta Kausaite 2; Jurgis Kuliesius 2; Baniukevic Julija 2; Viktor Mazeiko 2; Voroanovic Jaroslav 2; Arunas Ramanavicius 2 1State Research Institute Center for Innovative Medicine, Division of Immunotechnology, Vilnius, Lithuania; 2Vilnius University, NanoTechnas – Center of Nanotechnology and Materials Science, Faculty or Chemistry, Vilnius, Lithuania

There are known several ways suitable for the synthesis of conducting polymers: chemical [1], electrochemical [2] and relatively new enzymatic [3-10] synthesis. Glucose oxidase was found as very suitable enzyme for enzymatic synthesis of conducting polymers including polypyrrole [3-8], polianailine [9,10] and polytiophene. The aim of this presentation is to overview major achievements of authors in enzymatic synthesis of conducting polymers. Mechanisms of chemical [1] and enzymatic [3-10] synthesis will be presented. Enzymatic synthesis of polypyrrole [3-8], polyaniline [3,9,10], and polythiophene will be evaluated. Modification of electrodes by enzymatically synthesized conducting polymers will be evaluated and advantages of such polymers will be discussed. Possibilities to change and even to tune kinetic parameters of enzymatic biosensors by enzymatic synthesis of conducting polymers will be discussed [8,9]. Results of electrochemical [3-6,8-10], atomic force microscopy [7] measurements and some spectroscopic data [3-10] of enzymatically formed polymers will be presented. Direct electron transfer from enzymes towards electrodes via some conducting polymers will be discussed [2]. Application of enzymatic synthesis for visualisation of immobilized redox enzymes [4] will be introduced. References: 1 K Leonavicius et al. Langmuir 2011, 17, 10970-10976 2 Y Oztekin et al. Biosensors and Bioelectronics 2011, 26, 2541–2546 3 A. Kausaite-Minkstimiene et al. Sensors and Actuators B Chemical (2011) 158, 278–285 4. A. Ramanaviciene et al. Microchimica. Acta 2011, 175, 79-86 5. A. Ramanavicius et al. Sensors and. Actuators B Chemical 2005, 111-112 532–539 6. A. Ramanavicius et al. Synthetic Metals 2006, 156, 409-413 7. A. Ramanaviciene et al. Colloids and Surfaces B: Biointerfaces, 2006, 48, 159-166 8. A Ramanavicius et al. Analyst, 2008, 133, 1083-1089 9. A Kausaite-Minkstimiene et al. Biosensors and Bioelectronics 2010, 26, 790-797 10. A Kausaite et al. Polymer 2009, 50, 1846–1851.

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Colloidal behaviors of poly(3,4-ethylenedioxythiophene)/TiO2 nanotube hybrid nanoparticles Ozlem Erol ; H. Ibrahim Unal Gazi University, Chemistry Department, Ankara, Turkey

Colloidal dispersions play an important role as major components in a wide variety of well-established rheological fluids. Among the commonly used conducting polymers, poly(3,4-ethylenedioxythiophene) (PEDOT) has attracted attention in recent years due to its excellent properties [1]. Without covalent bonding between the organic and inorganic phases, the interactions between the two phases are likely to be weak, because of the relatively small interfacial areas caused by nanoparticle agglomeration and/or because of limited electron transport across the oxide/polymer interfaces. Thus, in this study, our goal is to make interfacial interactions between the two components of the nanocomposite more prominent via covalent bonding PEDOT and TiO2. In this study, covalently bonded conducting polymer, PEDOT, coated TiO2 nanoparticles having nanotube structure was prepared and characterized by spectroscopic, morphological, thermal, and electrical techniques. Firstly, TiO2 nanotube (TiNt) was prepared from TiO2 nanoparticles via a simple hydrothermal process using concentrated NaOH solution. Secondly, TiNt were silanized with 3-aminopropyltriethoxysilane (APTS-TiNt). Then, silanized TiNt containing amino functional group was reacted with 3-thiophene acetic acid to obtain thiophene ended TiNt (3-TA-TiNt). Finally, 3,4-ethylenedioxythiophene was polymerized in the presence of pre-prepared 3-TA-TiNt to obtain hybrid nanoparticles (PEDOT-TiNt). Electrokinetic properties and surface charges of the materials were determined by electrophoretic measurements. Change in surface properties of TiNt were confirmed by zeta-potential measurements. The effects of pH, temperature, various surfactants and electrolytes on the electrokinetic properties of the colloidal nanoparticles were investigated. Acknowledgements: TUBITAK of Turkey (111T637) and COST CM1101 Action. [1] J. Roncali , P. Blanchard, P. Frère, J. Mater. Chem., 2005, 15, 1589-1610.

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Synthesis and characterization of meso/macroporous TiO2-P2O5 and TiO2-P2O5-SiO2 materials, using highly concentrated emulsions as templates Jordi Esquena 1; Lourdes A. Perez-Carrillo 2; Susana Vilchez 1; Conxita Solans 1 1IQAC-CSIC, Barcelona, Spain; 2University of Guadalajara, Guadalajara, Mexico

Bimodal porous structures are used in technological applications, because of mass-transport and adsorbent properties, with applications in catalysis, absorption, separation, energy storage, etc. [1]. Bimodal porous textures can lead to interesting properties, since the mesopores (2-50 nm) impart high specific surface area, while the macropores (>50 nm) ensure rapid transport of reactive species. These materials can be obtained by templating in highly concentrated emulsions [2,3]. This type of emulsions are characterized by a volume fraction of the disperse phase greater than 0.74, which is the critical volume of the most compact arrangement of uniform spherical droplets [4,5]. Their structure consists of polyhedral and polydisperse droplets separated by a thin film of continuous phase [6]. In the present work, hybrid TiO2-P2O5 and TiO2-P2O5-SiO2 materials, with a bimodal pore size distribution, have been obtained by a two-step method: templating in polystyrene monoliths, which were polymerized in highly concentrated emulsions. Both hybrids showed well interconnected macropores, with a morphology that resembles that of highly concentrated emulsions. TiO2-P2O5-SiO2 material showed high specific surface (> 300 m2/g) with both small mesopores (~ 7 nm) and macropores (> 500 nm). TiO2-P2O5 materials were also obtained with bimodal pore size distribution. The specific surface area was higher than 100 m2/g pore and pore volume was larger than 0.5 mL/g. References: [1] Dacquin, J.P.; Dhainaut, J.; Duprez, D.; Royer, S.; Lee, A.F.; Wilson, K.; J. Am. Chem. Soc. 2009, 131, 12896-12897. [2] Esquena, J.; Sankar, G.S.R.R.; Solans, C.; Langmuir 2003, 19, 2983. [3] Maekawa, H.; Esquena, J.; Bishop, S.; Solans, C.; Chmelka, B. F. Adv. Mater. 2003, 15, 591. [4] Lissant, K. J. J. Colloid Interface Sci. 1966, 22, 462. [5] Princen, H. M. J. Colloid Interface Sci. 1979, 71, 55. [6] Solans, C.; Esquena, J.; Azemar, N.; Rodríguez, C.; Kunieda, H. in Emulsions: Structure, Stability and Interactions (Ed: D.N. Petsev), Elsevier, Amsterdam 2004.

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Silica-coating as protective shell for the risk management of nanoparticles Davide Gardini ; Magda Blosi ; Camilla Delpivo ; Anna Luisa Costa National Research Council of Italy (CNR) - Institute of Science and Technology for Ceramics (ISTEC), Faenza, Italy

Nanoparticles surface functionalization through the application of organic/inorganic coatings allows to create new materials (hybrids, core-shell structures) with engineered properties. In particular, coatings based on SiO2 have attracted high attention due to their hydrophilicity, biocompatibility, chemical and thermal stability even in aqueous media. The present work is addressed to the production and characterization of SiO2-coatings on TiO2 and Ag nanoparticles dispersed in aqueous solutions (commercial nanosols) with the aim to manage the potential risk that such nanoparticles may generate within an occupational exposure scenario (activities performed on behalf of EU-FP7 - Collaborative Project SANOWORK). Two different approaches were followed: i) a colloidal approach, based on principles of hetero-coagulation, in which TiO2 or Ag and SiO2 opposite charged nanoparticles are forced to coagulate each other, with a hierarchical structure imposed by their relative size and weight ratio; ii) a chemical approach that consists in nucleation of silica phase on TiO2 or Ag nanoparticles seeds by starting from silica precursor solutions. In the last case, the nanosized confinement of growing silica phase is the most critical step. Physicochemical properties such as zeta potential, particle size distribution, specific surface area, micro-Raman patterns and SEM/TEM morphology allow a deep control of both processes, as well as a full characterization of the resulting products. Finally, phenomena that can predict toxicity of uncoated or SiO2-coated TiO2 or Ag nanoparticles, were evaluated and compared in order to check the efficiency of these new engineered nanoparticles.

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Purification of water from nanosized pollutants Gospodinka Gicheva 1; Georgi Yordanov 2 1University of Mining and Geology, Department of Chemistry, Sofia, Bulgaria; 2Sofia University “St. Kliment Ohridski”, Faculty of Chemistry and Pharmacy, Sofia, Bulgaria

The extensive worldwide development of nanotechnological products in recent years resulted in introduction of various nanosized colloidal materials in practice (cosmetics, electronics, etc.). The toxicity of some nanomaterials is still not completely evaluated, while others are well-known to be toxic even at low concentrations. Such materials could pose a danger to the human health and could have a quite negative environmental impact. Toxic and potentially dangerous nanomaterials could be incidentally released in natural waters, which could raise a serious ecological problem. Therefore, effective methods for purification of water from nanosized pollutants are currently highly required. In this report we make a review of the toxic and the potentially dangerous nanomaterials and show the basic concepts of various technologies that could be utilized for purification of water from such type of pollutants. We demonstrate the efficiency of some modified conventional strategies for water purification in the treatment of waters that contain water-dispersible inorganic nanoparticles. Newly developed methods, based on the specific properties of nanoparticles are also presented. Acknowledgements: This work was supported by the Bulgarian National Science Fund (project MU 03-86/2011) and CMST COST Action CM1101.

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Self-assembly of polymer-graphene oxide barrier films Vilcinskas Karolis 1; Ger Koper 1; Fokko Mulder 2 1Delft University of Technology, Chemical Engineering, Delft, Netherlands; 2Delft University of Technology, Radiation Radionuclides and Reactors, Delft, Netherlands

Proton exchange membrane fuel cells, in which chemical energy of the fuel is converted directly into electrical energy via electrochemical reactions, have been recognized as the most promising clean energy converting devices. The bipolar plates are key elements of the fuel cells and play major role in distribution of the fuel and oxidant within the cell, current collection and facilitation of the heat and water management. To meet these performance requirements, bipolar plates should exhibit such properties like: a) high electrical and thermal conductivities; b) gas impermeability; c) thermal and chemical stabilities; d) good mechanical properties. Pure graphite is well recognized for its good electrical & thermal conductivities and corrosion resistance, however poor mechanical properties and gas leakage are the main drawbacks. On the other hand, metals and alloys exhibit excellent gas impermeability and mechanical resistance, but susceptibility to corrosion, growth of less conductive oxide layer and risk to poison the catalyst are typical limitations. Graphene and its derivatives are very promising materials to exploit due their high electrical and thermal conductivities, good mechanical strength and impermeability to gases. Graphene itself is too brittle to serve independently, hence in this study we incorporated graphene oxide (GO) between polymeric matrix using the layer-by-layer (LbL) technique (Lan Yu, Yun-Soo Lim et al. Synthetic Metals 162 (2012) 710-714). Generally, LbL self-assembly proceeds as follows: a charged substrate was immersed in a poly(ethylenimine) solution to adsorb the first monolayer and rinsed with distilled water. Then the film is immersed in a solution of GO and rinsed with distilled water. This procedure is repeated until the desired number of layers is achieved. The previous study reported that only a few layers of GO 30-40 nm thick dramatically decreased the oxygen transfer ration and enhanced electrical conductivity. Here, we will report on hydrogen permeability in conjunction with thermal and electrical conductivities.

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CeO2, CuO and CuxCe(1-x)Oy NPs prepared in O/W microemulsions Andrea-Victoria Vela-Gonzalez 1; Kelly Pemartin 2; Alejandro Garcia-Garcia 3; Magali Boutonnet 4; Conxita Solans 2; Margarlta Sanchez-Dominguez 5 1Centro de Investigación en Materiales Avanzados, S.C. Unidad Monterrey, GENES-Group of Embedded Nanomaterials for Energy Scavenging, Apodaca, Mexico; 2Institute for Advanced Chemistry of Catalonia (IQAC-CSIC) and CIBER en Biotecnología, Biomateriales y Nanomedicina (CIBER-BBN), Barcelona, Spain; 3Universidad Autonoma de Nuevo Leon, Facultad de Ciencias Quimicas, San Nicolas de los Garza, Mexico; 4Kungliga Tekniska Högskolan (KTH), School of Chemistry, Div. of Chemical Technology, Stockholm, Sweden; 5Centro de Investigación en Materiales Avanzados, S.C. (CIMAV), Unidad Monterrey, GENES-Group of Embedded Nanomaterials for Energy Scavenging, Apodaca, Mexico

Introducing different metals into CeO2 affects its characteristics, and in particular the oxygen vacancies, which in turn determine some of its properties such as oxygen storage capability, which is important for several applications. A method based on oil-in-water (O/W) microemulsions as confined reaction media was recently developed for the preparation of metallic and metal oxide nanoparticles[1]. The advantage of this new approach is the use of water as a continuous phase, more environmentally friendly and less costly than organic solvents generally used in the traditional water-in-oil (W/O) microemulsion method. In this study, the synthesis of Cerium oxide (CeO2) doped with Copper (Cu) using the O/W microemulsion reaction method has been explored; the pure oxides (CeO2 and CuO) were synthesized and characterized as well for comparison purposes. Cu/Ce molar ratio from 5/95 to 30/70, resulted in mixed Cu/Ce oxide in which Cu is incorporated in the crystal structure of cubic CeO2. At Cu/Ce molar ratio (50/50), a predominant phase of mixed Cu/Ce oxide and an excess CuO phase were obtained. The nanoparticles were characterized by X-Ray Diffraction (XRD), High Resolution Transmission Electron Microscopy (HRTEM), Scanning Electron Microscopy (SEM) BET and TGA/DSC. In addition, magnetization studies were carried out in order to explore the potential of the mixed oxides in spintronics. These materials are of high interest in various applications such as electrodes in fuel cells[2], gas sensors[3] and as efficient catalysts for catalytic reaction[4]. [1] Sánchez-Domínguez M, Boutonnet M and Solans C (2009) J. Nanoparticle Research, 11: 1823 [2] (a) Inoue T, Setoguchi T, Eguchi K and Arai H (1989) Solid State Ionics, 34, 285 (b) Park S, Vohs J M, Gorte RJ (2000) Nature, 404, 265 (c) Gorte RJ, Vohs JM, McIntosch S (2004) Solid State Ionics, 175, 1 [3] Lampe U, Gerblinger J, Meixner H (1992) Sens Actuators, B7, 787 [4] Kusar H, Hocevar S, Levec J (2006) Applied Catalysis B: Environmental 63, 194

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Electrokinetic studies of protein adsorption on latex particles Anna Bratek-Skicki ; Zbigniew Adamczyk ; Paulina Dabrowska Jerzy Haber Institute of Catalysis and Surface Chemistry, PAS, Cracow, Poland

The interaction between proteins, antibodies (antigens) and polymer colloids is of considerable importance when developing particle-enhanced immunoassays. [1] The popularity of this diagnostic technology is illustrated by the fact that in 1992 there were over 200 commercial reagents available employing this approach [1]. In such systems the colloidal aggregation of immunolatex has to be caused only by the presence of the corresponding antigen. Based on this assumption it is necessary to obtain immunolatex with a high colloidal stability in order to avoid an unspecific aggregation of the system due to physico-chemical conditions of the medium (pH, ionic strength, temperature, etc.). In this work, adsorption of bovine fibrinogen on positively and negatively charged polystyrene latex particles was studied using the concentration depletion method combined with AFM detection of residual protein after adsorption. Measurements were carried out for a broad range of pH (3.5-11) and ionic strength 10-3 - 0.15 M, NaCl. First, bulk physicochemical properties of fibrinogen and the latex particle suspension were characterized for this range of pH and ionic strength. Zeta potential and the number of uncompensated (electrokinetic) charges on the protein were determined from microelectrophoretic measurements. Afterwards, systematic measurements of the electrophoretic mobility of fibrinogen covered latex were carried out as a function of the amount of adsorbed protein, expressed as surface concentration.[2] Based on these experimental data, an efficient procedure of preparing fibrinogen covered latex particles of a controlled monolayer structure and coverage was developed. [1] Ortega-Vinuesa JL, Hidalgo-Alvarez, R., Biotech Bioeng., 47:633, 1995 [2] Z.Adamczyk, A.Bratek-Skicki, P.Dabrowska, M. Nattich-Rak, Langmuir, 2012, 28 (1), pp 474–485.

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Impact of nanoparticles on the interfacial properties and structure of lipid monolayers Eduardo Guzman ; Michele Ferrari ; Eva Santini ; Libero Liggieri ; Francesca Ravera Consiglio Nazionale delle Ricerche-CNR, Istituto per l'Energetica e l'interfasi (IENI)-UOS Genova, Genova, Italy

The study of the interaction between nanoparticles and surfactants presents interest in the field of physical-chemistry of colloids and interfaces due to the importance of these systems in the stabilization of foams and emulsions. Moreover, when natural surfactant are concerned, this type of study may provide a better understanding of the potential adverse impact of such interactions on the properties and structures of biologically-relevant systems such as biomembranes, lung surfactant. This work is focused on the effect of nanoparticles with different chemical nature (silica, carbon, titania) and surface hydrophilic-phobic characteristics on the mechanical surface properties and on the structure of lipid layers, both for pure lipids and mixtures of them. For this purpose, the study of spread monolayers at the air/water interface (Langmuir films) and solid-supported film (Langmuir-Blodgett films, LB) is made. The results evidence that the presence of nanoparticles induces important modifications in the physico-chemical properties and structure of lipid monolayers ascribable to the hindering of the molecular packing and the changes of the interfacial composition. The Atomic Force Microscopy (AFM) images of LB films allows explaining the observed modifications due to the penetration of nanoparticles to the monolayer. The structural characterization of solid-supported films together to the physico-chemical characterization of fluid films allows proposing a scenario where the penetration of lipid monolayers by nanoparticles reduces the area available to the lipid molecules that modifies the interactions along the monolayer affecting the reorganization of the molecules at the interface. The interfacial study here presented leads to the conclusion that the behaviour of interfacial layers of lipids may be affected by the presence of nanoparticles in the environment. This might be correlated to negative modifications in the normal physiological response of biological relevant systems.

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Complexation of lysozyme with sodium poly(styrenesulfonate) Lara Stajner ; Josip Pozar ; Davor Kovacevic University of Zagreb, Department of Chemistry, Zagreb, Croatia

Interactions between a protein and an oppositely charged polyelectrolyte in solution could, in the appropriate experimental conditions (i.e. pH, ionic strength, type of added supporting electrolyte, concentration, etc.), lead to the formation of protein-polyelectrolyte complexes. In this study we examined the interactions between aqueous solutions of lysozyme and sodium poly(styrenesulfonate) (NaPSS) as the model system for investigating such formation processes. The effect of pH (pH = 3.1, pH = 4.6 and pH = 7.5), protein and polyelectrolyte concentration and titration direction on lysozyme-NaPSS complexation was investigated at t = 25 °C and at Ic = 0.01 M. The experimental methods used were electrophoretic mobility measurements (i.e. zeta potential determination), particle size measurements and isothermal titration microcalorimetry. Our results confirm that the all applied methods are useful in the process of investigation of protein-polyelectrolyte complexation. It was observed that the effect of both pH as well as protein and/or polyelectrolyte concentration on the process of lysozyme-sodium poly(styrenesulfonate) complex formation should not be underestimated. Additionally, it was confirmed that isothermal titration microcalorimetry experiments could be, when properly interpreted, very helpful in elucidating the investigated complexation processes.

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Controlling bacterial adhesion via surface micro/nano-patterning Stefano Perni 1; Polina Prokopovich 2 1University of Birmingham, School of Chemical Engineering, Birmingham, United Kingdom; 2Cardiff University, School of Pharmacy and Pharmaceutical Sciences, Cardiff, United Kingdom

Microorganisms can attach to surfaces forming a layer of cells often embedded in a polymeric matrix; some of these biofilms are undesired as consequence of their pathogenicity such as: in food processing plants, in hospitals and on the surfaces of medical devices; other, such in: biofilters, biofuel cells and engineered biofilms, are favoured because of their properties and metabolic activities. A laser system was utilized with micro- and nano- pulsed ablation to perform macro- and nano-patterning on silicon samples. Conical features with various diameters were created on the surface changing the power and the pulse duration with consequent depths being 1, 2, 6 and 9 µm, respectively. Suspensions of E. coli and S. epidermidis were placed in contact with the silicone samples and bacteria were allowed to adhere for 5 hours; the attached cells were determined with using Live/Dead staining. Results show that the distance between features did not have a significant effect on the number of cells attached for both bacteria species; whereas cones with diameters of 25 and 30 µm enhanced the number of both microorganisms on the surface compared to unpatterned samples. Whilst cones of 20 and 40 µm interfered with the biofilm formation. Bacterial cells were predominantly identified on the valleys around features and not on the top of the cones. Our results show that it is possible to favor or hinder bacterial adhesion on silicone interfaces through patterning. The possibility of avoiding biofilm formation on silicone, the material predominantly used in urinary catheters, is a possible approach to prevent Catheter Associated Infections (CAIs) that pose a serious risk to patients and an economic burden to health providers.

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Evaluation of immobilization technique influence on the efficiency of immunosensors Almira Ramanaviciene 1; Asta Kausaite-Minkstimiene 2; Zigmas Balevicius 2; Asta Makaraviciute 2; Baleviciute Ieva 2; Kirlyte Justina 2; Yasemin Oztekin 3; Arunas Ramanavicius 2 1State Research Institute Center for Innovative Medicine,, Division of Immunotechnology, Vilnius, Lithuania; 2Vilnius University, NanoTechnas – Center of Nanotechnology and Materials Science, Faculty or Chemistry, Vilnius, Lithuania; 3Selcuk University,, Department of Chemistry, Faculty of Science,, Konya, Turkey

During the last decade immunosensors have been the subject of an increasing interest of application as an alternative immunoassay technique in many areas, such as clinical diagnostics, biochemical analysis, environmental monitoring, food quality and biological research. Recently a number of detection techniques including electrochemical impedance spectroscopy [1], micro-mechanical transducers [2], surface plasmon resonance (SPR) [3] and simultaneous exploitation of several techniques has been used for registration of the analytical signal. The sensitivity of an immunosensor depends on the surface concentration of immobilized antibodies, their remaining antigen binding ability and appropriate orientation of these molecules The major objective of this study was evaluation and comparison of different immobilization techniques on the sensitivity of developed optical immunosensors. The evaluated SPR-chip modification techniques were: (i) random immobilization of intact-antibodies via self–assembled monolayers; (ii) random immobilization of intact-antibodies within carboxymethyl dextran hydrogel; (iii) oriented coupling of intact-antibodies via Fc-fragment to protein-G layer assembled on self–assembled monolayer; (iv) oriented immobilization of fragmented antibodies via their native thiol-groups directly coupled to the gold [4]. References: [1] Ramanavicius A., Finkelsteinas A., Cesiulis H., Ramanaviciene A., Bioelectrochemistry (2010) 79, 11-16. [2] Ramanaviciene A., Virzonis D., Vanagas G. Ramanavicius A., Analyst, (2010) 135, 1531 1534. [3] Kausaite-Minkstimiene A., Ramanaviciene A., Ramanavicius A., Analyst (2009) 134, 2051-2057. [4] Kausaite-Minkstimiene A., Ramanaviciene A., Kirlyte J., Ramanavicius A., Analytical Chemistry (2010) 82, 6401-6408. Acknowledgement: This research was funded in part by a Grant No MIP-059/2012 from the Research Council of Lithuania.

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Multi-functional micro-containers constructed from molecularly imprinted nanoparticles Xiantao Shen ; Changgang Xu ; Khan Mohammad Ahsan Uddin ; Lei Ye Division of Pure and Applied Biochemistry, Lund University, Lund, Sweden

Molecularly imprinted polymers (MIPs) are artificial receptors generated by template-directed polymerization. Because of their chemical robustness and molecular recognition capability, MIPs have great potential to act as modular building blocks to construct advanced functional materials and devices for a wide range of applications. Solid particles can directly self-assemble at liquid-liquid interface, and the resulted emulsion is often referred to as a Pickering emulsion. Pickering emulsions have been employed to fabricate polymer vesicles with a colloidal armor. Among the complex colloid-based materials, micro-containers with well-defined structures have attracted more and more interests because these materials have many potential applications. Until now, the micro-containers constructed from colloidal particles have showed no molecular selectivity. By combining molecular imprinting and Pickering emulsion, we developed a novel method to generate micro-containers (colloidosomes) having multiple functions. The micro-containers were prepared from Pickering emulsions based on MIP nanoparticles, followed by an interfacial chemical cross-linking using Cu(I)-catalyzed azide-alkyne 1,3-dipolar cycloaddition reaction (CuAAC). The combination of high selectivity of MIP nanoparticles with the high internal volume of the micro-containers opened some interesting possibilities: i) selective accumulation and separation of target molecules; ii) controlled release of bioactive peptides triggered by template binding; iiii) incorporation of additional molecular receptors/reporters to realize simultaneous detection of multiple molecular targets. Two examples of the MIP based complex structures, magnetic micro-containers and fluorescent micro-containers will be presented.

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In-situ formation of lipidic bupivacaine-loaded formulations: SAXS characterization and in vitro drug release properties Anan Yaghmur 1; Susan Weng Larsen 1; Jesper Østergaard 1; Henrik Jensen 1; Claus Larsen 1; Mechthild Schmitt 2; Arto Urtti 2; Michael Rappolt 3 1University of Copenhagen, Department of Pharmacy, School of Pharmaceutical Sciences, Faculty of Health and Medical Sciences, Copenhagen, Denmark; 2University of Helsinki, Centre for Drug Research, Helsinki, Finland; 3Austrian Academy of Sciences, Institute of Biophysics and Nanosystems Research (IBN), Graz, Austria

The dynamical behaviour of local anaesthetic bupivacaine (BUP)-loaded L2 and H2 phase precursors (BUP preformulations), which are attractive as efficient injectable nanocarriers for the sustained release of drugs, was investigated upon rapid exposure to phosphate buffer at 37 °C [1]. To determine such structural events in situ, a combination of synchrotron SAXS with remote controlled addition of buffer was used. This study attempted a detailed structural analysis of the role of the dynamical hydration during the formation of nanoscaled BUP-loaded non-lamellar structures. The structural mechanism and the possible transition pathways to approach the full hydration and equilibrium conditions were highlighted for three different precursors of inverted type micellar solution (L2) and a H2 phase. It is interesting to note that the obtained results reveal a relatively fast rearrangement of the lipid and solubilized BUP molecules in excess PBS 7.4 since the H2 structure formed upon the hydration of the L2 phase approaches within about 1000 sec that of the corresponding equilibrated full hydrated system. Most strikingly, none of the observed H2 phase transitions from the self-assembled preformulation are explainable by a simple one-step mechanism, but always an intermediate Pn3m phase forms. In this contribution, we discuss also the effects of variations in the lipid composition and/or BUP concentration on the drug release in vitro profiles and the structure of the liquid crystalline phases and microemulsions, which were investigated in the presence of the the distilled glycerol monooleate Myverol 18-99K (GMO) and medium-chain triglycerides (MCT) [2]. The studies reveal that both the nanostructures and the BUP release rates are highly sensitive sensitive to pH changes. References: [1] A. Yaghmur, S. W. Larsen, M. Schmitt, J. Østergaard, C. Larsen, H. Jensen, A. Urtti and M. Rappolt. Soft Matter 2011, 7, 8291. [2] A. Yaghmur, M. Rappolt, J. Østergaard, C. Larsen, and S. W. Larsen. Langmuir 2012, 28, 2881.

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Nano-Composite Gel composed of Micellar Network and Silica Nano-Particles. A combined SAXS and SANS Study. Kell Mortensen 1; Masahiko Annaka 2 1University of Copenhagen, Niels Bohr Institute, Frederiksberg, Denmark; 2Kyushu University, Department of Chemistry, Fukuoka, Japan

Organic-inorganic hybrid materials have attracted attention since they can be tailored to combine the advantages of organic polymers with those of inorganic components yielding materials, which possess enhanced mechanical properties, chemical resistance, optical quality, and other useful properties, which arise from the synergetic interaction of the individual organic and inorganic constituents. Nature also combines different types of macromolecules in order to form gels with outstanding physical properties. One example is the lens, which projects the optical image on the retina together with the cornea. With the attempt to make a artificial composite material with mechanical properties, light transmission factor and refractive index that makes it suitable for implant of intraocular lens, we have studied a nano-composite material composed of hydrophobically-modified poly(ethylene glycol) (HM-PEG) and silica OCAPS nano-particles [1,2], using combined SANS and SAXS. The structural studies show that the polymers form a micellar network that order into a bcc-ordered phase when appropriate concentrated. The network structure easily aligns into mono or twin-domain texture upon shear. The OCAPS nano-particles are very well dispersed within water as well as within the polymer gel structure. The dispersion characteristics remain apparently unchanged upon loading into the micellar structure, but the different contrasts factors of SANS and SAXS also unambiguously show that the form factor of the micelles changes markedly upon OCAPS loading, convincingly showing that the OPACS nano-particles are located within specific regions of the micellar network structure. REFERENCES: 1) Annaka, M. Mortensen K., Vigild, M.E., Matsuura T., Tsuji, S., Ueda, T., Tsujinaka H. Biomacromolecules 12, 2011, 4011-21. 2) Annaka, M. Mortensen K., Matsuura T., Ito M,, Nochioka, K., and Ogata, N. Soft Matter 2012.

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WEDNESDAY

Wednesday 5 Sept: Poster presented 17.00-18.00 P3:1

Morphogenesis from deformation of biomimetic microcapsules Antoine Bailly 1; Laurent Heux 1; Catherine Quilliet 2 1CNRS-CERMAV, Grenoble, France; 2CNRS-LIPHY, Grenoble, France

The deformation of plant cells during their growth can generate various anisotropic shapes. The envelop of the growing cells, also called primary wall of plants, is a thin, flexible and extensible layer made of a network of cellulose microfibrils linked by hemicellulose tethers, that can have directional extension. The goal of this work is to elaborate biomimetic microcapsules with structures similar to the plant primary walls and explore their deformation under mechanical stress. For that purpose, we took advantage of the strong interaction of cellulose nanocrystals (the microfibrils sub-elements) with xyloglucan (the most common hemicellulose) already used to build planar multilayer systems [1]. In order to reproduce the cell geometry, we successfully build multilayered microcapsules from cellulose nanocrystals and xyloglucans, by combining oil in water emulsions with dimensions around 20 µm with layer-by-layer deposit, leading to biomimetic microcapsules. The regularity of the layer deposition has been followed by selective fluorescent tagging and the wall thickness and organization was characterized by electron microscopy. Upon drying and evaporation of the oily core, the deflated microcapsules exhibited various shapes as revealed by 3D reconstruction from confocal microscopy slices. We are now investigating the relationships between the obtained shapes in relation to the characteristic dimensions and the mechanical properties of the wall [2]. The control of the capsule size and thickness allows exploring various situations in terms of deformation behavior. References: [1] B. Jean, L. Heux, F. Dubreuil, G. Chambat and F. Cousin, Non-electrostatic building of biomimetic cellulose-xyloglucan multilayers, Langmuir, 25(7), 3920-3923 (2009) [2] C. Quilliet, C. Zoldesi, C. Riera, A. van Blaaderen, and A. Imhof Anisotropic colloids through non-trivial buckling Eur. Phys. J. E, 27, 13{20} (2008)

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P3:2 Wednesday 5 Sept: Poster presented 18.00-19.00

Polymeric nanocapsules and nanospheres for photodynamic therapy use; optimization and stability Urszula Bazylinska ; Skiba Ewa ; Kazimiera A. Wilk Wroclaw University of Technology, Organic and Pharmaceutical Technology Group, Faculty of Chemistry, Wroclaw, Poland

Poorly water-soluble drugs as cyanine–type photosensitizers [1,2] can be used in many encapsulation technologies to improve their dissolution performance by means of template-mediated processes, i.e., interfacial polymerization, subsequent adsorption or interfacial nanoprecipitation of polyelectrolytes. The most applicable nanoprecipitation method - also called solvent displacement or interfacial deposition - is based on spontaneous emulsification of the organic internal phase with the dissolved polymer into the aqueous external phase [3]. The aim of our contribution is to report on a convenient method of fabrication of nanocarriers loaded with the hydrophobic cyanine-type photosensitizer IR-786. The drug delivery properties of polylactic acid (PLA) and polycaprolactone (PCL) nanocapsules and nanospheres (stabilized by Cremophor EL and containing, in the case of nanocapsules, coconut oil as liquid core), have been assessed in terms of their colloidal stability and ability to incorporate the cyanine. DLS measurements confirmed the particle diameter below 150 nm and AFM and SEM its morphology and shape. Doppler electrophoresis provided a large negative ζ-potential. UV-vis was applied to determine the encapsulation efficiency (about 90%) and to determine the dye release characteristics. The colloidal stability of nanoproducts was checked upon nanofiltration, freeze drying and storage in the dark. Our methodologies made it possible to obtain stable and long sustained IR-786-loaded monodispersed oil-cored nanocapsules and nanospheres under physiological conditions as well as after nanoseparation, therefore, they provide suitable nanocarriers for in vivo administration. 1. J. Pietkiewicz, K. Zieliñska, J. Saczko, J. Kulbacka, M. Majkowski, K. A. Wilk, Eur. J. Pharm. Sci. 39 (2010) 322-335. 2. U. Bazyliñska, R. Skrzela, K. Szczepanowicz, P. Warszyñski, K. A. Wilk, Soft Matter 7 (2011) 6113-6124. 3. C. E. Mora-Huertas, H. Fessi, A. Elaissari, Int. J. Pharm. 385 (2010) 113-142.

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Study of the biophysical interactions between core-shell nanocarriers and liquid-supported model of cell membranes Desire' Di Silvio 1; Paul McNaughter 2; Andrew Mayes 2; Roger Parker 3; Francesca Baldelli Bombelli 1 1University of East Anglia, school of pharmacy, Norwich, United Kingdom; 2University of East Anglia, school of chemistry, Norwich, United Kingdom; 3Institute of Food Research, Norwich, United Kingdom

Nanomedicine is a growing multidisciplinary area of research, which aims to develop novel nanomaterials that can combine diagnostic and therapeutic components in one unique particle. Huge efforts have been done to better understand how the physical-chemical properties of nanoparticles (NPs) affect their interaction with the cell. For this purpose, the study of the interactions of engineered NPs with the biomolecoles in the biological environment is a key point. In fact, NPs in the biological environment change their identity being covered by a layer of proteins and other biomolecules: protein corona NPs are a new entity with different properties from the original with clear relevance to the further interaction with the biological matter. In this work, we have developed and characterized monodispersed polymer coated NPs for controlled release of drug in ideal conditions and in biological media. We synthesized both gold and magnetite NPs functionalized with different positive and negative charged moieties and PEG. NPs were characterized by DLS, TEM, ICP-AES, Z-potential and FTIR. The protein corona of these NPs was studied by SDS-PAGE, agarose gel and MS. Physical-chemical interactions of these NPs in buffer and serum with supported lipid bilayers of different compositions (cell membrane models) were studied by AFM and QCM. Among Nps differences in size and charge were highlighted because of the different cores and the different surface cover moieties. These properties influence the interaction with the proteins present in the biological media and cause different corona formation around the Nps that affect the nature and strength of interactions with lipid bilayers. These preliminary experiments on NPs show some factors that can contribute to modify interactions with membrane model, focusing in particular on surface properties of NPs and considering them not just in ideal condition (PBS) but also in biological media. The data obtained as well as the optimized techniques will be useful for further experiments in which a specific interaction between a couple ligand-receptors will be studied.

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Sonochemical formation/activation of metal alloy based heterogeneous catalysts Jana Dulle 1; Ekaterina V. Skorb 2; Daria V. Andreeva 1 1University of Bayreuth, Physical Chemistry II, Bayreuth, Germany; 2Max Planck Institute of Colloids and Interfaces, Golm, Germany

We present a new way of heterogeneous catalyst preparation by the formation/activation of metal and metal alloy particles using high intensity ultrasound. Our mesoporous multimetal nanocomposites are applied in heterogeneous catalysis. Physical and chemical interactions of cavitation bubbles generated by ultrasound and metal particles are responsible for the modifications of the metal structures. We applied the sonochemical formation/activation method to the following potential catalysts: commercial Al/Ni[1], home-made Al/Cu[2] and Al/Pd. The modified materials were analyzed by transmission and scanning electron microscopy, powder X-ray diffraction, solid state 27Al NMR, X-ray photoelectron spectroscopy, and physisorption. The structure and morphology of these metal alloy based nanocomposites can be controlled by duration and intensity of the ultrasonication[3]. We observed a microphase separation in metal alloys as well as self-regulated redox reactions of their components after high intensity ultrasound treatment. The activation of metal alloys by ultrasound leads to formation of mesoporous structures, increase of surface area, and high catalytic activity. In these mesoporous materials aluminum plays the role of the support and Ni, Cu, and Pd supply the active centers for catalysis. Surface areas up to 200 m2g-1 and pores with a narrow pore size distribution with a mean diameter of 4 nm can be achieved. These alloys modified and activated by high intensity ultrasound catalyze hydrogenation[1], dehydrogenation[2], and A3-coupling reactions. References: [1] J. Dulle et al., Adv. Funct. Mater. 2012, doi: 10.1002/adfm.201200437 [2] J. Schäferhans et al., Chem.-Eur. J. 2011, 17, 12254-12256 [3] E. V. Skorb et al., Nanoscale 2011, 3, 985-993

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The interaction of superhydrophobic and hydrophobic coatings on magnesium surface with aqueous solutions Alexandre Emelyanenko ; Andrey Pashinin ; Ludmila Boinovich A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Moscow, Russian Federation

The methods for the design of highly- and superhydrophobic nanocomposite coatings on the surface of magnesium with oxide layers will be described. To investigate the peculiarities of the interaction of such coatings with water, NaCl, and H2SO4 aqueous solutions we have studied the parameters of three phase coexistence, obtained by the method of sessile drop. It is shown, that simultaneous analysis of contact angle, contact diameter of sessile drop and liquid/vapour surface tension allows one to relate the degradation of superhydrophobic and hydrophobic state with reversible and irreversible processes taking place due to the interaction between magnesium surface and aqueous solutions. The method recently developed by us allows one to estimate both the portion of wetted area and the intrinsic wettability state (hydrophobic versus hydrophilic) of elements of texture on the magnesium surface and to prove durability of developed coatings in contact with aggressive media.

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Isotropic diffusion weighting in microscopically anisotropic systems with PGSE NMR using a magic-angle sweep of the q-vector Stefanie Eriksson ; Samo Lasic ; Daniel Topgaard Lund University, Physical Chemistry, Lund, Sweden

Polydomain lyotropic liquid crystals are microscopically anisotropic materials with locally anisotropic diffusion. If the orientation dispersity of the domains is isotropic then the global diffusion is isotropic. The diffusion in vesicle dispersions, on the other hand, is isotropic on a microscopic scale although restricted inside the vesicles. Microscopic anisotropy in globally isotropic materials can be detected by NMR experiment such as single-PGSE which shows a characteristic echo attenuation curvature (1). More recently, double-PGSE has been used to show the existence of microscopic anisotropy in globally isotropic media by the use of collinear and orthogonal displacement encoding (2). One problem with these methods is that they have low sensitivity to microscopic anisotropy since restricted isotropic diffusion, as in vesicles, gives a decrease in echo attenuation, which can be misinterpreted as to stem from anisotropic diffusion. We present a new diffusion-NMR pulse sequence for measuring the mean isotropic diffusion in microscopically anisotropic media. The sequence called iso-PGSE is a single-PGSE augmented with sinusoidal gradients in three different directions, which achieves an isotropic diffusion weighting by making the q-vector sweep in a cone, spanning at the magic angle. We present a method where the echo-attenuation curve from a conventional single-PGSE is analyzed simultaneously with the attenuation curve from the iso-PGSE. We have applied this method on lyotropic liquid crystals and yeast cells dispersed in water. Furthermore this method could be used in compounds of vesicles embedded in e.g. lamellar phase liquid crystals to measure the fraction of intravesicle water in the system. 1. Callaghan PT & Soderman O, J Phys Chem-Us 87(10):1737-1744 (1983) 2. Callaghan PT & Komlosh ME, Magn Reson Chem 40:S15-S19 (2002)

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Immobilization and characterization of human serum albumin onto polyelectrolyte coated ITO surface Mustafa Ozmen ; Imren Hatay Patir ; Mustafa Ersoz University of Selcuk, Department of Chemistry, Konya, Turkey

Much attention has been paid to the surface modification of an indium tin oxide (ITO) electrode by assembling functional small molecules via chemical linkages. It is well known that the polyelectrolytes can be used as monolayer for linking specific functional groups onto many solid substrates including silicon, aluminum oxide, and indium tin oxide [1-3]. Thus, the poly (allylamine hydrochloride), PAH, and poly(styrene sulfonate), PSS were employed as molecular bridge linking onto the thin ITO film in our experiments. Herein, modification of ITO thin films with surface attachment chemistry has been studied. Firstly, ITO films are pretreated in order to activate the surface further by creating a greater density of hydroxyl groups. The activated ITO surface is modified secondly with negatively and positively charged polyelectrolytes to establish a stable layer which is charged positively and subsequently albumin molecule which electrostatically binds to the charged surface. Characterization of the surfaces utilizing techniques like contact angle, atomic force microscopy, scanning electrochemical microscopy and cyclic voltammetry is also reported. References: [1] Vodouhe C, Schmittbuhl M, Boulmedais F, Bagnard D, Vautier D, Schaaf P, et al. Biomaterials 2005, 26, 545–554. [2] Boulmedais F, Frisch B, Etienne O, Lavalle P, Picart C, Ogier J, et al., Biomaterials 2004, 25, 2003–2011. [3] Reibetanz, U., Claus, C., Typlt, E., Hofmann, J., and Donath, E., Macromol. Biosci. 2006, 6, 153–160.

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Synthesis of silver-deposited silanized magnetite nanoparticles and their biosensor application Betul Ertekin 1; Mustafa Ozmen 2; Mustafa Ersoz 2 1University of Nevsehir, Department of Chemistry, Nevsehir, Turkey; 2University of Selcuk, Department of Chemistry, Konya, Turkey

Magnetic nanoparticles have been the focus of much research recently because they possess attractive properties which could see potential use in catalysis, biomedicine, magnetic resonance imaging, data storage, and enviromental remediation. Furthermore, silver nanoparticles are receiving great atteention due to their unique optical properties associated with surface plasmon resonance. In order to improve the stability of metal nanoparticles, various procedures have been employed to obtain silica-metal composites. This is because colloidal silica, which is thermostable and resistant to coagulation, avoids the aggregation of the metal particles [1-2]. In this work, we have firstly synthesized spherical magnetite particles with a mean diameter of ~12 nm, and then the as-prepared superparamagnetic particles are coated with SiO2 onto which Ag nanoaggregates are finally assembled to endow them with both the superparamagnetism and biologic activity. A series of experiments characterizing the sensor were carried out, including measurement mode, reproducibility, response time, linear range and effects of pH, concentration and co-existing substances. References: [1] J. Tashkourian, M.R. Hormozi-Nezhad, J. Khodaveisi, R. Dashti, Sensors and Actuators B:Chemical 158 (2011) 185-189. [2] K.S. Shin, Y.K. Cho, J.Y. Choi, K. Kim, Applied Catalysis A:General 413 (2012) 170-175.

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Membrane- and mediator-less miniature nanostructured biofuel cells for ex vivo and in vivo applications Magnus Falk 1; Viktor Andoralov 1; Marcus Granmo 2; Dmitry Suyatin 3; Jens Schouenborg 2; Javier Sotres 4; Roland Ludwig 5; Olga Morozova 6; Zoltan Blum 4; Thomas Arnebrant 4; Ruzgas Tautgirdas 4; Sergey Shleev 4 1Malmö University, Malmö, Sweden; 2Lund University, Neuronano research center, Lund, Sweden; 3Lund University, Division of Solid State Physics, The Nanometer Structure Consortium, Lund, Sweden; 4Malmö University, Biomedical Science, Malmö, Sweden; 5BOKU-University of Natural Resources and Life Sciences, Vienna, Austria; 6National Research Centre "Kurchatov Institute", Moscow, Russian Federation

We present the first report on miniature ex vivo and in vivo operating direct electron transfer (DET) based biofuel cells (BFCs). Specifically, we show that a mediator-, cofactor-, and membrane-less, enzymatic FC, operating in human tears as well as implanted in the brain of a rat, do produce significant amounts of electrical energy, enough to power modern electronic devices. We have previously reported on a membrane- and mediator-less sugar/oxygen BFC fabricated from three-dimensonal gold nanoparticle-modified electrodes based on immobilized sugar oxidizing and oxygen reducing enzymes operating in simple buffers and human physiological liquids. Cellobiose dehydrogenase and bilirubin oxidase were used as anodic and cathodic bioelements, respectively. A similar design was used in the current studies, however, miniaturization of the biomodified electrodes was performed for ex vivo (using tears) and in vivo (implanted in rat brain) investigations of biodevices. Miniature electrodes were fabricated using gold microwires (0.1 mm diameter) modified with gold nanoparticles (ca. 17 nm in diameter). Detailed investigations of the created nanostructures were done using SEM, AFM, and electrochemistry. Electrodes were modified with redox enzymes and rigorous bioelectrochemical characterisation of separate micrsoscale bioanodes and biocathodes as well as combined bioelectrodes (BFC) were performed in simple buffers and complex human physiological fluids. In human basal tears, the following characteristics of BFCs were obtained: open-circuit voltage of 0.57 V, power density (PD) of 0.8 µW cm-2 at 0.50 V cell voltage. After 24 h of continuous operation at 0.51 V biodevices still retained similar PD profile. The maximal power of biodevices was strongly limited by quite low concentration of glucose available in tears. When glucose/oxygen BFCs were implanted in rat brain the following characteristics were registered: 0.55 V open-circuit voltage, about 2 µW cm-2 maximum PD at a cell voltage of 0.4 V, and more than 2 h operational half-life time. The maximal power of biodevices was strongly limited by quite low concentration of oxygen available in brain interstitial fluid.

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Cement: a two thousand year old nano-colloid Emiliano Fratini 1; Francesca Ridi 1; Chen Sow-Hsin 2; Piero Baglioni 1 1University of Florence, Department of Chemistry and CSGI, Florence, Italy; 2MIT, Department of Nuclear Science and Engineering, Cambridge, United States

Since Roman times, cement is one of the synthetic materials with the largest production and usage by mankind. The understanding the structure of cement and the water transport phenomena in cement matrices is of great interest either from an industrial and a scientific point of view. In this talk the structural evidences at the nanoscale level of the calcium-silicate-hydrate (C-S-H) building block in evolving cement pastes will be discussed. C-S-H is the major hydration product in a cement paste and the mechanical properties of cured cements completely rely on it. We reports the detailed structure of mature C-S-H as determined by Small-Angle Neutron Scattering (SANS) as a function of the C-S-H water content. The main results shows that C-S-H building blocks are basically disk-like objects with alternating water and calcium silicate layers. The globules pack together in a fractal structure with a cut-off size of about 67 nm and a mass fractal dimension varying from 2.75 to 2.58 as a function of the equilibrium water content [1]. [1] W.-S. Chiang, E. Fratini, P. Baglioni, D. Liu, and S.-H. Chen “Microstructure Determination of Calcium-Silicate-Hydrate Globules by Small-Angle Neutron Scattering” J. Phys. Chem. C DOI: 10.1021/jp300745g

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Polymer / nanoparticle interactions: From hydrohobic to hydrophilic materials Jerome Fresnais CNRS, Laboratoire PECSA, Paris, France

Stabilization of nanoparticles in water or hydrophobic solvents is one major issue in nanoscience. Polymers, such as polyelectrolytes or PDMS, are good candidates for nanoparticles stabilization. I will present new results dealing with nanoparticles / polymer interactions to prepare isolated and/or aggregated magnetic nanoparticles for different applications. Magnetic nanorods with fluorescent dyes can be prepared in one step. Another example is the synthesis of magnetically functionnalyzed PDMS matrix for microfluidics applications.

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Inhibition of iron-gall ink corrosion and deacidification of historically valuable manuscripts by using earth-alkaline Hydroxide Rodorico Giorgi ; Giovanna Poggi ; Nicola Toccafondi ; Piero Baglioni University of Florence, Csgi-Department of Chemistry, Sesto Fiorentino, Italy

This contribution reports on the synthesis of earth alkaline hydroxide nanoparticles, and their application of their dispersions in nonaqueous solvents to inhibit degradation of paper and manuscripts. Calcium and magnesium hydroxide nanoparticles obtained by using a novel synthetic procedure, are shown to be very efficient in controlling paper’s pH to prevent cellulose from acid hydrolysis and oxidative ink-induced corrosion. A single-step treatment was used to inhibit degradation of model paper containing different inks, prepared according to a 17th-century recipe. The effects of the treatment were evaluated upon to accelerated aging. Physico-chemical characterization of nanoparticles through electron microscopy (SEM-TEM), DLS, and XRD was also reported. The efficacy of nanoparticles treatment was evaluated by monitoring the polymerization degree of cellulose and by thermal analysis (DSC and DTG). The pH stabilization at about 6.5-7.5 was shown to be effective in preventing paper from degradation. The inhibiting action of magnesium hydroxide nanoparticles was compared to magnesium oxide particles that constitute the active agent in one of the most used mass-deacidification method (Bookkeeper). Historically valuable manuscripts have been also deacidified and protected with nanoparticles.

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QCM-D as a method for monitoring enzyme immobilization in mesoporous silica particles Hanna Gustafsson 1; Christian Thorn 2; Holmberg Krister 1 1Chemical and Biological Engineering/Chalmers University of Technology, Applied Surface Chemistry, Gothenburg, Sweden; 2Chemical and Biological Engineering/Chalmers University of Technology, Industrial Biotechnology, Gothenburg, Sweden

Enzyme immobilization in mesoporous materials is a field of great interest, with applications in biocatalysis and biosensing. However, the immobilization process is not well understood and has mainly been studied by indirect measurements. This work demonstrates a direct method for real time study of enzyme immobilization in mesoporous silica particles using quartz crystal microbalance with dissipation (QCM-D). Prior to the enzyme immobilization silica-coated crystals were grafted with amine groups followed by adsorption of small (40 nm), spherical mesoporous silica particles. The influence of pH on the immobilization were studied using two different enzymes; lipase from Rhizopus oryzae and feruloyl esterase FoFAEC. Additionally, the enzyme immobilization into mesoporous particles was compared to a flat surface, non-porous silica particles and rehydroxylated mesoporus particles. The results show that the silica particles adsorbed readily to the amine-grafted surface and no desorption was observed at pH 5-6 whereas a minor continuous desorption occurred at pH 7-8. The frequency shift was extensively larger for the two enzymes in the mesoporous particles, implying a larger loading compared to both a flat silica surface and non-porous particles. The enzymes were also more stably immobilized in the porous particles and the results indicate that the enzymes are situated inside the pores and not only on the outer surface. QCM-D is a promising method for studying enzyme immobilization in mesoporous silica particles in real time and may be used to study other interactions with porous particles.

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Structural study of mesoporous crystals with bicontinuous structures Lu Han 1; Keiichi Miyasaka 2; Osamu Terasaki 3; Shunai Che 1 1Shanghai Jiao Tong University, School of Chemistry and Chemical Engineering, Shanghai, China; 2Korea Advanced Institute of Science and Technology, Graduate School of EEWS (WCU), Daejeon, Republic of Korea; 3Stockholm University, Department of Materials and Environmental Chemistry, Stockholm, Sweden

Considerable research has been directed surrounding mesoporous crystals (MCs). Compared to the lyotropic liquid crystals, a synthesis-field diagram for MCs is more complex, and MCs can be immobilized for further characterization. The bicontinuous MCs, with gyroid (G), diamond (D) and primitive (P) minimal surfaces, have attracted a great deal of interest because of their complex and highly symmetric structures in which two disconnected but interwoven mesoporous networks divided by a silica wall grow along a continuously curved surface. Herein, MCs have been synthesized by using anionic surfactant N-stearoyl-L-glutamic acid (C18GluA) as template in the presence of nonionic co-surfactant C16(EO)10 (Brij-56). It has been found the mesostructures changed in an order that cage-type → 2D cylindrical (C) → intergrowth (C and D) → intergrowth (C and G) → D → G → lamellar (L), with the increase of Brij-56 and reaction temperature. The local surfactant packing parameter was obtained from the electron crystallography reconstruction results by calculating mean curvatures and Gaussian curvatures from the equi-potential surface. This is the first report that a full synthesis-field diagram of MCs including D and G was found and the structures can be directly compared. In this synthesis system, we observed novel silica mesoporous crystal spheres with polyhedral hollows (icosahedral, decahedral, Wulff polyhedral, etc.) formed by the reverse multiply twinned D surface. Of note, the twinning structures of bicontinuous minimal surfaces cannot be interpreted by the classical twinning theory and has not been solved before. Here the structural resolution of both D and G twinning will be discussed in detail. Besides, the defects and epitaxial intergrowth of the bicontinuous MCs will be also shown. References: [1] Kresge, C. T.; Leonowicz, M. E.; Roth, W. J.; Vartuli, J. C.; Beck, J. S. Nature 1992, 359, 710. [2] Han, L.; Xiong, P.; Bai, J.; Che, S. J. Am. Chem. Soc. 2011, 133, 6106. [3] Han, L.; Miyasaka, K.; Terasaki, O.; Che, S. J. Am. Chem. Soc. 2011, 133, 11524. [4] Han, L.; Miyasaka, K.; Terasaki, O.; Che, S. In Preparation.

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Facile synthesis of silver nanoparticle necklaces on sub-micron silica spheres Mathias Hanisch 1; Mirza Mackovic 2; Nicola Taccardi 3; Erdmann Spiecker 2; Robin N. Klupp Taylor 1 1FAU Erlangen-Nuremberg, Institute of Particle Technology, Erlangen, Germany; 2FAU Erlangen-Nuremberg, Center for Nanoanalysis and Electron Microscopy, Erlangen, Germany; 3FAU Erlangen-Nuremberg, Institute of Chemical Reaction Engineering, Erlangen, Germany

One-dimensional nanostructures comprising noble metals are promising materials for applications e.g. in electronic or optical devices, due to properties which arise from their anisotropic morphology. The widespread exploitation of anisotropic nanostructures requires more effort to develop and understand simple and scalable routes to achieve complex morphologies. In this contribution we report how one-dimensional silver nanoparticle assemblies on sub-micron silica spheres can be synthesized in the absence of explicitly added reducing and templating agents. Our procedure includes the liquid phase treatment of colloidal silica with the ammoniacal silver complex (Ag(NH3)2

+) followed by washing, deposition on a substrate and aging under ambient conditions. Electron microscopy reveals that, 5 – 10 nm silver nanoparticles are arranged in necklace-like assemblies on the silica spheres and up to a certain distance from them on the substrate. We investigate the formation of the nanoparticle necklaces by varying simple parameters of the liquid phase and aging treatments. The ongoing work focusses on the mechanistic understanding of the nanoparticle necklace formation by the synergistic chemical behavior of the used materials, namely Ag(NH3)2

+ and amorphous silica particles. Moreover we try to cover a larger area with necklace coated silica in order to gain a better control over structure and be able to determine relevant properties. Besides potential uses in transparent electrical conductive coatings, substrates for surface-enhanced Raman spectroscopy (SERS) or for electromagnetic shielding this material could be particularly interesting for possible novel optical properties of the structures. In the latter case we believe that mesh-coated silica particles formed by their further metallization may display resonances in their magnetization at optical frequencies and thus meets requirements for the formation of, for example, negative index metamaterials.

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The self assembled monoloyers (SAMs) of silanes on ITO electrodes and their electrochemical behaviour Imren Hatay Patir ; Mustafa Ersoz University of Selcuk, Department of Chemistry, Konya, Turkey

Self assembled monolayers (SAMs) offer an excellent model system to investigate the structural arrangement and interfacial phenomena. It provides a way to control the structure and to tune the physical and chemical properties of solid–liquid and liquid–liquid interfaces [1-3]. In the present work, we have investigated the formation and characterization of Self-assembled Monolayer (SAM) films of two different silanes compound on indium tin oxide (ITO) surfaces. 3-aminopropyl triethoxysilane (APTES) and 3-chloropropyl trimethoxysilane (CPTMS) silane molecules having different domains namely substrate binding domain (siloxanes), electron transport region (aliphatic and aromatic spacer) and terminal functional groups (–NH2, –Cl groups) are used for the study in order to tune the electron transfer (ET) behaviour across SAM modified electrode–electrolyte interface. Structural characterization of stepwise changes of these modified surfaces is performed using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). Contact angle measurements is carried out to evaluate surface hydrophilicity/ hydrophobicity. Electron transfer (ET) behaviour of ITO/CPTMS and ITO/APTES surfaces have been investigated by electrochemical techniques namely cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) using [Fe(CN)6]3-/4- redox couple as a probe. The charge transfer rate constant (Rct) values of these surfaces are determined from EIS by fitting them to an appropriate equivalent circuit model. It has been suggested that ITO/CPTMS and ITO/APTES electrode surfaces show different electron transfer behaviour across the electrode-electrolyte interface depending on the structure of chosen silane molecules. References: [1] A. Ulman, An Introduction to Ultrathin Organic Films, Academic Press, Boston, 1991. [2] C.J. Miller, I. Rubinstein (Eds.), Physical Electrochemistry: Principles, Methods and Applications, Marcel Dekker, New York, 1995. [3] A. Ulman, Chem. Soc. Rev. 96 (1996) 1533.

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Lithium ion electro-insertion in self-assembled films from TiO2, chitosan, and silver nanoparticles Fritz Huguenin ; Wellington Gomes ; Nelson Galiote FFCLRP/USP, Ribeirão Preto, Brazil

Self-assembled materials consisting of anatase TiO2, chitosan and silver nanoparticles (AgNPs) were obtained by the layer-by-layer (LbL) method, aiming at their application as electrodes for lithium-ion and lithium-air batteries. The method used herein allowed for linear growth of visually homogeneous films composed of TiO2, TiO2/chitosan, and TiO2/chitosan /AgNP with 15 bilayers. Nyquist diagrams of electrochemical impedance spectroscopy indicate trapping effects during the lithium ion electro-insertion in host matrix formed from TiO2 nanoparticles. On the other hand, no trapping effects were detected in the self-assembled nanocomposites. The presence of chitosan enabled establishment of an electrostatic shield between the lithium ions and the TiO2 sites with higher negative charge, thereby raising the ionic mobility and consequently increasing the energy storage capacity. AgNPs were stabilized in chitosan and inserted into the nanoarchitecture, so as to enhance the specific capacity. This should provide new conducting pathways and connect isolated TiO2 particles in the host matrix. This work suggests that nanoarchitectures with suitable properties can be spontaneously obtained, leading to better performance for enhancing the charge transport rate into the host matrices. The obtained materials displayed suitable properties for use as electrodes in lithium and lithium-air batteries.

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The effect of cosurfactants on the physicochemical properties of Crodamol PC-based nanoemulsions Malgorzata Jaworska ; Elzbieta Sikora ; Jan Ogonowski Cracow Univeristy of Technology, Institute of Organic Chemistry and Technology, Cracow, Poland

Nanoemulsions are a new form of cosmetics products. They show some advantages comparing to classic emulsions: relatively easily penetrate into the skin, exhibit a high degree of hydration and soften the skin and have a very good user properties (ease of spreading on the skin, no greasy feeling). Thanks to their structure they can also transport both hydrophilic and hydrophobic active substances to the skin. The aim of this work was preparation and characterization of nano- and microemulsions containing Crodamol PC as the oil phase. Crodamol PC is the propylene glycol diester of caprylic/capric acid. It offers several functional benefits with applications in a number of cosmetic and pharmaceutical products (lipophilic vehicle, skin permeation enhancer, oxidatively stable, non-greasy emollient, good spreading agent, low viscosity) [1,2]. The emulsions were prepared by phase inversion composition method, one of the low energy emulsification method, at room temperature (25°C). Different kind of polisorbates (ethoxylated eters of sorbitan and fatty acids) were used as the emulsifiers. Additionally the short-chain alcohols (ethanol, 1-propanol, isopropanol, buthanol) were used as cosurfactants. The particles size distribution in the prepared products was analyzed by DLS measurement technique (Dynamic Light Scattering) using Zetasizer Nano ZS (Malvern Instruments, UK). Rheological studies of the systems were carried out using Brookfield Rheometer Model - R/S Plus. The obtained results showed that the studied emulsions are high dispersed systems (the droplet sizes are in the range between 100 – 500 nm). Moreover the kind and the concentration of the applied cosurfactant significantly influence the stability of Crodamol PC based emulsion systems. References: (1) http://pceurope.crodadirect.com (2) http://health.crodadirect.com

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Modification of surface properties of latex coatings for enhanced print quality of silver nanoparticle ink Helka Juvonen ; Anni Maattanen ; Petri Ihalainen ; Jouko Peltonen Abo Akademi University, Center of Excellence in Functional Materials, Laboratory of Physical Chemistry, Turku, Finland

Currently, there is an increasing interest of using paper as a substrate for printed electronics. The motivation lies in the fact that paper is a truly low-cost, environmentally friendly, and widely used flexible substrate in everyday life. Controlling the spreading and achieving homogeneous drying of the functional inks on a substrate is important when printing electronic components requiring high print resolution and precision, e.g. transistors. Ink-jet printing offers a possibility for high resolution printing together with easy modification of the print pattern. However, the accumulation of the solid material to the perimeter of the printed droplet or line during the drying, i.e. the coffee ring effect1, is a commonly observed problem in ink-jet printing that reduces the print quality. The problem has been addressed previously e.g. by tuning the properties of the ink, adjusting the properties of the substrate or controlling the drying time of the printed inks.2, 3 In this study, the surface properties of latex-coated papers were tuned to enhance the print quality of nanoparticle silver ink. Infrared (IR) irradiation enabled the nanoscale modification of topography, material properties (adhesion and elasticity) and surface energy as a function of irradiation time. The changes were followed by torsional harmonic atomic force microscopy (TH-AFM) which enables simultaneous high-resolution mapping of topography, tip-sample adhesion and reduced elastic modulus. In addition, contact angle measurements were used for surface energy determination. The coffee ring effect in the printed silver ink droplet could be reduced by the IR treatment of the surface. References 1) R. D. Deegan et al. Nature, 1997, 389, 827 - 829 2) D. Soltman and V. Subramanian Langmuir, 2008, 24, 2224 – 2231 3) R. Dou and B. Derby Langmuir, 2012, 28, 5331 – 5338.

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Studying the microwave-assisted synthesis of CdSe quantum dots by small-angle X-ray scattering Andreas Keilbach 1; Mojtaba Mirhosseini Moghaddam 2; Mostafa Baghbanzadeh 2; C. Oliver Kappe 2 1Anton Paar GmbH, Graz, Austria; 2Karl-Franzens-University Graz, Christian Doppler Laboratory for Microwave Chemistry (CDLMC) and Institute of Chemistry, Graz, Austria

Quantum dots (QDs) are inorganic, semiconducting nanoparticles showing exceptional photophysical properties depending on their respective size and shape. Traditionally synthesized by conventional wet-chemical techniques, the use of microwave irradiation as a non-classical source of energy has become increasingly popular. Here we report on a small-angle X-ray scattering (SAXS) study of the synthesis of CdSe nanoparticles under microwave irradiation. The influence of various synthesis parameters on the size of the resulting CdSe quantum dots was evaluated. In a first step, the effect of the time of addition of a capping agent (oleic acid) during the ongoing synthesis was investigated. For this purpose, a special modification allowing for a “hot injection” of the oleic acid under ongoing microwave irradiation was designed. The resulting product solutions were then characterized by SAXS using the SAXSess mc2 system and the respective size distributions were calculated from the scattering curves. In a second series of experiments, the influence of different Cadmium precursors Cd(X)2 on the size of the resulting QDs was studied. The SAXS experiments (and additional TEM micrographs of selected samples) showed that the diameter of the nanoparticles can be tuned within a range from approximately 1.2 nm to 4 nm while keeping the size distribution perfectly monodisperse, thus allowing to fine-tune the properties of the QDs. Additionally, we have found that there are no non-thermal effects of the microwave irradiation by carrying out the reactions in strongly absorbing (SiC) and non-absorbing (Pyrex) vessels. The size distributions obtained from the SAXS experiments of these solutions overlapped perfectly. The results of this study show that SAXS is a fast and reliable characterization method for the systematic study on the synthesis of all kinds of nanoparticles.

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Transient colloidal stability controls the particle size of mesoporous silica SBA-15 Tomas Kjellman 1; Juanfang Ruan 1; Yasuhiro Sakamoto 2; Viveka Alfredsson 1 1Lund University, Physical Chemistry, Lund, Sweden; 2Stockholm University, MMK, Stockholm, Sweden

We have studied the formation of mesoporous silica SBA-151(2D hexagonal) with cryogenic TEM, High Resolution SEM and dynamic light scattering.2 A poly(ethyleneoxide)-poly(propyleneoxide)-poly(ethyleneoxide) triblock copolymer, Pluronic, is used as structure director in the synthesis. Cryo-TEM images from the first few minutes of synthesis suggests that particles grow via formation of composite Pluronic-silica-water “flocs” in agreement with previous results.3 These “flocs” coalesce in a seemingly random manner but, despite this, the final particles show uniform size and morphology. From these results a hypothesis of (transient) colloidal stability as a controlling mechanism for the particle size and particle morphology is suggested. We argue that Pluronic brushes, possibly in combination with silica brushes, decorate the “floc”/water interface and provide some steric stabilization. As the “flocs” coalesce the total surface area/volume ratio decreases leading to higher brush coverage and a more efficient steric stabilization. This dictates the particle size. However, as the silica continues to polymerize the steric stability is gradually lost and eventually the particles aggregate. During this aggregation step the particles retain their individual identity. The hypothesis is tested by influencing the properties of the Pluronic molecules by various additions. (1) Zhao, D.; Huo, Q.; Feng, J.; Chmelka, B. F.; Stucky, G. D. J. Am. Chem. Soc. 1998, 120, 6024. (2) Ruan, J.; Kjellman, T.; Sakamoto, Y.; Alfredsson, V. Submitted to Langmuir 2012. (3) Flodström, K.; Wennerström, H.; Alfredsson, V. Langmuir 2004, 20, 680.

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Probing nanomechanical structure-property relationships of micro- and nanofibers by AFM bending experiments Daniel Kluge 1; Benedikt Neugirg 1; Julia Singer 2; Hans-Werner Schmidt 2; Andreas Fery 1 1University of Bayreuth, Physical Chemistry II, Bayreuth, Germany; 2University of Bayreuth, Macromolecular Chemistry I, Bayreuth, Germany

Micro- and nanofibers are important structural elements in biomaterials, tissues and other functional materials, where one of their main functions is providing mechanical stability. Characterizing these small-scale fibers requires highly specialized techniques beyond standard methods for macroscopic materials. In our contribution, we focus on nanoscale bending experiments of fibers suspended over channels and demonstrate their applicability for a wide variety of fiber systems. We show results on bending perpendicular and parallel to the substrate plane and discuss major advantages of these two bending modes, for example validation of boundary conditions, direct integration of optical methods and detailed investigation of the mechanical properties beyond linear elastic deformations. Our experiments allow us to investigate the properties of numerous novel materials and we will present in detail our studies on supramolecular benzenetrisamide aggregates. Small changes in their molecular structure can significantly influence their morphology, which makes them suitable for "bottom-up" tailored materials. We look into the effect of the molecular structure on their mechanical behavior and compare benzenetrisamide fibers obtained by self-assembly and electrospinning.

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Influence of ionic strength and pH on electroactive properties of the multilayer films containing conductive nanoparticles Marta Kolasinska-Sojka ; Anna Pajor-Swierzy ; Piotr Warszynski Jerzy Haber Institute of Catalysis and Surface Chemistry PAS, Krakow, Poland

Composite metal nanoparticle/polymer films combine the sensitivity and response of polymers to external stimuli (e.g. polymer swelling) with high charge transport ability of metal particles, thus allowing formation of materials with tunable stimuli responsive conductivity. It makes them great candidates for chemical sensing especially when nanoparticles chosen are additionally sensitive to the presence of some particular compounds in the environment, i.e. hydrogen peroxide as Prussian blue (PB) nanoparticles. Nanocomposites: polyelectrolyte/PB nanoparticles were obtained using alternative adsorption from the solutions of polyions and PB. PB nanoparticles with dimeter of c.a. 10 nm were synthesized directly before deposition. Adsorption of Prussian blue NP on a polyelectrolyte monolayer/multilayer was proved by in situ experiments using QCM. It was found that the amount of Prussian blue deposited depended on the sort of polyelectrolyte used, pH value and ionic strength conditions chosen for deposition. Electroactive properties of polyelectrolyte multilayers with embedded Prussian Blue NP were studied using cyclic voltammetry in two different media: without or with hydrogen peroxide in electrolyte solution. Current registered depended on the amount of Prussian blue layers in the studied multilayer films increasing with number of Prussian blue layers. Some studies on the stability of electrodes modified with polyelectrolyte/Prussian blue composite films confirmed significant role of the outermost nafion layer, which increased the stability of the studied system. Additionally thickness and optical properties of chosen nanocomposites were determined using spectroscopic ellipsometry. Some dissimilarity in the refractive index spectra confirmed differences in the structure of nanocomposites dependent on the sort of underlaying polyelectrolyte layer. Acknowledgement:The work presented was supported by The HOMING PLUS PROGRAMME co-financed by the Foundation for Polish Science, as part of INNOVATIVE ECONOMY OPERATIONAL PROGRAMME 2007–2013 and by The National Science Centre Grant UMO-2011/01/D/ST5/04913.

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Investigation of viscoelastic properties of assembled gold nanoparticle mono- and multilayer structures using QCM-D Vida Krikstolaityte 1; Jildiz Hamit-Eminovski 2; Alejandro Barrantes 2; Arunas Ramanavicius 1; Laura Abariute 3; Gediminas Niaura 3; Thomas Arnebrant 2; Tautgirdas Ruzgas 2 1Vilnius University, Department of Physical Chemistry, Vilnius, Lithuania; 2Malmo University, Department of Biomedical Sciences, Malmo, Sweden; 3Institute of Chemistry, Center for Physical Sciences and Technology, Vilnius, Lithuania

Gold nanoparticles (AuNPs) are often used as a stable and electrically connecting (wiring) nanomaterial for designing powerful biofuel cells (BFCs) based on direct electron transfer (DET). In a recent work, it has been demonstrated that AuNPs enable DET of a laccase enzyme from Trametes hirsuta. In this work viscoelastic properties of AuNP mono- and multilayer structures have been investigated using Quartz Crystal Microbalance with Dissipation (QCM-D). The aim of this study is to develop BFC electrodes based on mono- and multilayer bio-nanostructures possessing different flexibility for enhanced applicability in living tissues and soft materials (e.g., miniature soft implants, catheters, synthetic membranes). Mono- and multilayer (4 layer) structures of AuNPs were assembled by exploiting layer-by-layer (LbL) method. Negatively charged AuNPs with an average diameter of 22 nm and a positively charged high- or low molecular weight surface active linkers, poly-L-lysine (PLL) and 1-(6-mercaptohexyl)pyridinium (MHP) chloride, respectively, were used. The mono- and multilayer assembling was performed using AuNP dispersions containing different salt concentrations, specifically, 0, 1, 10 and 20 mM of NaCl. A qualitative analysis of QCM-D data, i.e., the changes in frequency and dissipation, of the mono- and multilayers with respect to the ionic strength has been performed. The dissipation increased with increasing ionic strength. Additionally, from the dissipation data it can be also concluded that a more viscous AuNP multilayer structure is formed with increasing layer number and using a high molecular weight interlayer linker, e.g., PLL. Quantitative viscoelastic parameters, i.e., viscosity and shear modulus of the AuNP nanostructures were evaluated by the viscoelastic Voigt model.

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The shape evolution of cobalt ferrite in a one-pot synthesis Niall Maclean 1; Shinya Maenosono 2; Nguyen T K Thanh 3 1Universty College London, Deparment of Physics, London, United Kingdom; 2Japan Advanced Institute of Science and Technology, Nomi, United Kingdom; 3The Royal Institution of Great Britain, London, United Kingdom

Magnetic nanoparticles are very versatile and are expected to be highly promising for magnetic drug delivery, hyperthermia cancer treatment and magnetic particle imaging. For these biomedical applications, the magnetic nanoparticles should have the following characteristics: (i) large saturation magnetization and high magnetic susceptibility; (ii) superparamagnetism at room temperature, i.e. the magnetic moment fluctuates freely in the absence of a magnetic field thereby cancelling the magnetic attraction between particles, to avoid aggregation; (iii) size comparable to bio-molecules; (iv) a small size distribution, to ensure a homogeneous effect of the particle[1]. Currently the leading material within the field is magnetite, Fe3O4, which has FDA approval; however, this material is imperfect due to a low saturation magnetisation, 92 emu g-1[2]. Cobalt ferrite, CoFe2O4, is a similar inverse spinel structure to that of magnetite and due to the presence of the cobalt has a magnetic anisotropy which can make the material better suited for biomedical applications. The current syntheses of CoFe2O4 are dependent upon the production of iron oleate and cobalt oleate as starting materials and using these for thermal decomposition [3]. We propose a one pot synthesis from simple iron and cobalt acetylacetonate salts which will allow for the elucidation of the evolution of different shapes of cobalt ferrite nanoparticles. [1] Thanh, N.T.K. Magnetic Nanoparticles: from Fabrication to Clinical Applications. CRC Press, Taylor and Francis, (2012). [2] Sharif, I., Shokrollahi, H., and Amiri, S. J. of Magnetism and Magnetic Materials 324(6), 903 - 915 (2012). [3] Bao, N., Shen, L., An, W., Padhan, P., Heath Turner, C., and Gupta, A. Chemistry of Materials 21(14), 3458 - 3468 (2009).

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Improvement of nanotube based conductive inks via depletion interactions Laurent Maillaud ; Wilfrid Neri ; Alain Derre ; Alain Penicaud ; Cécile Zakri ; Philippe Poulin Centre de Recherche Paul Pascal (CRPP), Pessac, France

Carbon nanotubes (CNTs) are among the most promising candidates as an alternative to inorganic oxides for transparent conductive films. Because of their high aspect ratio and conductivity, they can form conductive networks at low concentrations. In this study, we develop conductive inks by dispersing CNTs in water in the presence of surfactants. The obtained dispersions are deposited on a flexible substrate using a scalable approach [1]. The key objective is the control of the network morphology to combine high conductivity and optical transmittance. This objective is achieved via the control of the interactions between the particles. Interactions affect the rheological, wetting and self-assembly properties of the CNTs. In particular, it is theoretically expected that weak attractive forces should promote local alignment of the CNTs along with a decrease of the percolation threshold [2,3]. Local alignment should lead to better electrical contacts. A lower percolation threshold should allow an increase in transmittance. We validate in this work these theoretical expectations. Cryo-TEM analyses show that increasing the surfactant concentration in the dispersion actually promotes contacts and local alignment of CNTs because of weak depletion forces induced by the surfactant micelles. It is also shown that weak attractive interactions result in an increase of the solution viscosity which yields improvements of processability. The control of the network morphology should lead to significant improvements of the performances of conductive transparent electrodes based on carbon nanotubes. References: [1] D. Budhadipta, et al, ACS NANO, vol3 (2009), pp. 835–843. [2] B.Vigolo et al, Science, 309 (2005), pp. 920-923. [3] A. V. Kyrylyuk et al, PNAS, 105 (2008), pp. 8221-8226.

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Synthesis of asymmetric composite dumbbells and their directed orientation in electric field induced assembly Daisuke Nagao ; Maki Sugimoto ; Ayako Okada ; Haruyuki Ishii ; Mikio Konno Tohoku University, Department of Chemical Engineering, Sendai, Japan

Assembly and directed orientation of anisotropic particles with an external ac electric field in a range from 1 kHz to 2 MHz were studied for asymmetric composite dumbbells incorporating a silica, titania, or titania/silica sphere. The asymmetric composite dumbbells, which were composed of a polymethylmethacrylate (PMMA)-coated sphere (core−shell part) and a polystyrene (PSt) lobe, were synthesized with a soap-free emulsion polymerization to prepare PMMA-coated inorganic spheres and another soap-free emulsion polymerization to form a polystyrene (PSt) lobe from the PMMA-coated inorganic spheres. The composite dumbbells dispersed in water were directly observed with optical microscopy. The dumbbells incorporating a silica sphere oriented parallel to an electric field in the whole frequency range and they formed a pearl chain structure at a high frequency of 2 MHz. The titania-incorporated dumbbells formed chain structures, in which they contacted their core−shell parts and oriented perpendicularly to a low-frequency (kHz) field, whereas they oriented parallel to a high-frequency (MHz) field. Since the alignment of dumbbells in the chains depends not only on the interparticle forces but also on the torque that the induced dipoles in the dumbbells experience in the electric field, the orientation of dumbbells perpendicular to the electric field was the case dominated by the interparticle force, whereas the other orientation was the case dominated by the torque. The present experiments show that the incorporation of inorganic dumbbells is an effective way to control the assembled structure and orientation with an electric field.

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Preparation of low-molecular organic crystals with gold luster and expression mechanism of gold luster Kazuya Nakajima ; Akiko Matsumoto ; Yutaka Takahashi ; Yukishige Kondo ; Yukishige Kondo Tokyo University of Science, Tokyo, Japan

Introduction: The color gold has immense aesthetic appeal and hence has been the preferred color for numerous products over generations. Recently, we prepared crystals with gold luster from an azobenzene derivative, bis[4-(3-methylbutoxy)phenyl]diazene (DC-azo). In this paper, we describe the detailed mechanism of formation of the gold luster exhibited by the DC-azo crystals. Experimental: The color and luster of the DC-azo crystals were investigated by UV-vis measurements, and the crystal structure was determined by X-ray diffraction (XRD) measurements. These were compared crystals of DC-azo derivatives, were synthesized in terms of molecular length and substituent. Results and Discussion:DC-azo was recrystallized from a mixture of acetone (good solvent) and water (poor solvent). The precipitated plate-like crystals were collected by filtration through filter paper. The crystals showed almost the same color and luster as metallic Au. Total reflectance measurements in the visible-light range indicated that the color of the DC-azo crystals was similar to that of metallic Au. In addition, the maximum specular reflectance was 21% over the visible-light range. SEM images showed that the DC-azo crystals have a layered structure in which a number of 10 µm-thick single crystals with smooth surfaces are stacked. We suggest that this layered structure is responsible for the gold luster. XRD measurements indicated that the DC-azo crystals have herringbone structures with a long-range d-spacing of 1.14 nm. These results indicate that to obtain gold luster, a stacked structure comprising plate-like single crystals with smooth surfaces is essential.

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Quantitative characterization of biomaterials and their interaction with living cells by atomic force microscopy Thomas Neicke ; Carmen Pettersson ; Tanja Neumann JPK Instruments AG, Berlin, Germany

Topography and mechanical properties are parameters influencing cell adhe-sion/motility, morphology, mechanics and cell development1-4. AFM combined with optical microscopy is a tool for high-res studying of morphology, and to map me-chanical and adhesive properties.The sensitivity of high-end AFM allows for resolving structures of <1 nm and forces on pN scale. Different imaging modes can resolve structures of biomaterials in physiological conditions without the Abbe diffraction limit. In force spectroscopy mode, interaction forces between the (modified) cantilever and any substrate can be investigated. Using Single Cell Force Spectroscopy (SCFS), cell-substrate or cell-cell interactions can be measured down to single protein unbinding. AFM can also serve as nano-indentation tool to analyse mechanical properties (e.g. Young’s modulus).The nanostructure of biomaterials and cell alignment on those structures have been resolved4,5. SCFS quantified the adhesion force and the contribution of different components, e.g. from the extra cellular matrix of living cells to implant materials as from cochlear implants6. Force-indentation measurements on cells using colloidal probes showed a significant effect of micro-patterned substrates on cellular elasticity2. Interaction forces from single molecule unbinding to cell adhesion and analysis of surface and mechanical properties of biomaterials and cells make AFM to a key technology in biomaterial research. Nano-mechanical analysis of cells increasingly gains in importance in different fields in cell biology like cancer research7 and developmental biology8. We present a strategy to comprehensively characterize biomaterials as well as their interaction with cells and influence on cell behavior. References: 1 Elter etal,Eur Biophys 2011. 2 McPhee etal, Med Biol C 2010. 3 Engler etal,Cell 2006. 4 Kirmse etal J Cell Sci 2010. 5 Cisneros etal, Small 2007. 6 Aliuos etal,Biomed Tech 2010. 7 Cross etal, Nat Nanotech 2007. 8 Krieg etal Nat Cell Biol 2008

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Zinc modified by ultrasound for photocatalytic wastewater treatment Silke Nemeth 1; Jana Dulle 1; Ekaterina V. Skorb 2; Daria V. Andreeva 1 1Universität Bayreuth, Physical Chemistry II, Bayreuth, Germany; 2Wissenschaftspark Golm, Max Planck Institute of Colloids and Interfaces, Golm, Germany

We present a new method for the formation of hedgehog-like zinc / zinc oxide structures with photocatalytic activity. Metallic zinc (Zn) powder was modified by high intensity ultrasound (US) to form ZnO nanorods on the surface of metallic Zn particles. The formation and morphology of the nanorods were investigated by powder-X-ray-diffraction (PXRD), scanning electron microscope (SEM), transmission electron microscope (TEM) and physisorption. We showed US modification of Zn is based on surface oxidation of metal by sonogenerated free radicals in a cycle-like manner. 10-min-sonication yielded the highest amount of nanorod-covered Zn particles. PXRD revealed formation of ZnO on the Zn particles. After 15-min-sonication the sonochemically grown oxide nanorods broke off the metallic particles and could be separated from them. Then the ZnO nanorods start growing again, covering the metal Zn surface. The microscopy (SEM, TEM) images showed US treatment of Zn particles leads to a hedgehog-like morphology, where the Zn particle surface was covered by zinc oxide nanorods. The unique morphology was most visible after 10-min-sonication, the samples were homogeneously covered by 180 nm ZnO nanorods. Using US we prepared nanostructured Zn-based material for photocatalysis. The homogeneously distributed ZnO nanorods on the metal surface exhibit high surface area and accessibility for substrate molecules. The catalytic activity of the modified Zn particles was tested by irradiating a solution of methyl orange with UV-light. The reaction was followed by UV-vis-spectroscopy. The coloration of the solution disappeared quickly under UV-irradiation when modified Zn was added to the solution. Without this catalyst we observed no change in coloration. The reaction rate constant depended linearly on the amount of catalyst used. The catalyst was reusable without further treatment or loss of activity. We showed US is a good method for the production of nanostructured Zn / ZnO materials.

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Solidified microemulsions Cécile Noirjean ; Fabienne Testard ; David Carrière CEA Saclay, LIONS, Gif sur Yvette, France

Solidified microemulsions are a new class of materials with high potential applications in many fields like synthesis, catalysis, optics… as well as proton conduction. Microemulsions are well-known isotropic nanostructured liquids, made with water, oil and surfactants (M. Kalhweit et al. Journal of Colloids and Interface Science, 1987, 118, 436-453). The versatility of their microstructure combined with high surface to volume ratio is the base of several applications (B. Abécassis et al. Soft Matter, 2009, 5, 974-978). Here, we use a polar or a nonpolar phase which is solid at room temperature. It is therefore possible to prepare microemulsions above their melting point and then cool down the mixture to obtain solidified microemulsions. Ideally, the as prepared material is a clear solid with the same nanostructure as the starting mixture and containing a large amount of liquid (H. Dave et al. Nature Materials, 2007, 6, 287-290). This type of materials has been to date poorly studied. We are particularly interested in studying the liquid-solid transition as it determines whether the initial structure of the microemulsion may be quenched. As a first system, we have focused on a system with solid oil phase (melting point: 55°C) and strong attractive interactions between oil and surfactants. We have determined the structure of clear isotropic mixtures, in the liquid state, by neutron and X-ray scattering. Unlike what is generally described for microemulsions, the system is not formed of water and oil domains separated by a surfactant film. The species rather seem to self-assemble into a smectic-like structure with no long-range order. The elucidation of this original structure has allowed us understanding the liquid-solid transition mechanism, and further opens unexpected perspectives in understanding original self-assembled structures of biological relevance.

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Investigating factors affecting water-in-diesel fuel nanoemulsions M.R. Noor El-Din 1; Sabrnal El-Hamouly 2; Marwa R. Mishrif 1; Ahmad M. Ragab 1; H. M. Mohamed 1 1Egyptian Petroleum Research Institute, Cairo, Egypt; 2Menoufia University, Menoufia, Egypt

In this work, water-in-diesel fuel nanoemulsions were prepared with mixed nonionic surfactants. Several mixtures of sorbitan monooleate and polyoxyethylene (20) sorbitan monooleate, resulting in different HLB (Hydrophilic-Lipophilic Balance) with values (9.6, 9.8, 10, 10.2 and 10.4) were prepared to achieve the optimal HLB value. Five emulsions with different water contents: 5, 6, 7, 8 and 9% (wt/wt) were prepared using high energy method at the optimum HLB (HLB=10). The effect of water, mixed surfactant concentration and HLB value on the droplet size has been studied. Also, the interfacial tension and thermodynamic properties of the individual and the blended emulsifiers were investigated. Droplet size of the prepared nanoemulsions was determined by dynamic light scattering and the nanoemulsion stability was assessed by measuring the variation of the droplet size as a function of time. From the obtained results, it was found that the mean droplet sizes was formed between 49.55 and 190.1 nm depending on HLB value, water content and surfactant concentration of the blended emulsifiers.

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Preparation and thermal tability of novel fluoroalkyl end-capped styrene dimer/silica nanocomposites Keita Okuno 1; Yuki Goto 1; Mari Iizuka 2; Masato Yoshida 2; Hideo Sawada 1 1Hirosaki University, Hirosaki, Japan; 2Shimane University, Izumo, Japan

In a variety of partially fluorinated polymers, especially, fluoroalkyl end-capped oligomers are attractive fluorinated polymeric materials, because they exhibit various unique properties such as high solubility, surface active properties, biological activities and nanometer size-controlled molecular aggregates which cannot be achieved by the corresponding non-fluorinated and randomly fluoroalkylated ones. [1] Especially, these fluoroalkyl end-capped oligomers were applied to the nanocomposite reactions with silica nanoparticles to afford the corresponding oligomers/silica nanocomposites. Some fluoroalkyl end-capped oligomers were found to exhibit a nonflammabe characteristic in the silica gel matrices even after calcination at 800 °C.[2] Here we report that a variety of fluoroalkyl end-capped styrene dimers/silica nanocomposites can be prepared by the sol-gel reactions of the corresponding dimers with tetraethoxysilane and silica nanoparticles under alkaline conditions. These fluoroalkylated styrene dimers/silica nanoocmposites were also applied to the encapsulation of low-molecular weight aromatic compounds to exhibit no weight loss behavior corresponding to the contents of the encapsulated ones even after calcination. [1] H. Sawada, Polym. Chem. 2012, 3, 46. [2] a) H. Sawada, T. Tashima, Y. Nishiyama, M. Kikuchi, G. Kostov, Y. Goto and B. Ameduri, Macromolecules 2011, 44, 1114; b) H. Sawada, M. Kikuchi, and M. Nishida, J. Polym. Sci. Part A; Polym. Chem. 2011, 49, 1070.

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Synthesis of magnetic core-shell Fe3O4-Ag nanoparticles for biomolecule immobilization Mustafa Ozmen ; Mustafa Ersoz ; Imren Hatay Patir ; Betul Ertekin University of Selcuk, Department of Chemistry, Konya, Turkey

Magnetic nanoparticles have attracted broad attention due to their potential applications in magnetic resonance imaging, data storage, drug delivery. Numerous research Works have been performed to evaluate the use of magnetic nanoparticles in the treatment of several diseases. Silver nanoparticles, liposomes, and polymeric micelle platforms have also been tested as drug delivery systems to target tumor cells and deliver anticarcinogenic drug in a controlled manner. Important progress has also been made in biomedical applications including separation and purification of biomolecules from the matrices. Up to now, application of silver-coated magnetic nanoparticles are relatively rare. Here, we report rapid and room temperature reaction synthesis of silver-coated magnetic in aqueous solution. Usability of developed core-shell nanoparticles were investigated in bioassay application. References: [1] U. Tamer, Y. Gundogdu, I.H. Boyaci, K. Pekmez, Journal of Nanoparticle Research 12 (2010) 1187-1196.

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Solid lipid nanoparticles as novel template for porous silica and hybrid anticancer drug loaded materials Andreea Pasc ; Marie-José Stébé ; Jean Luc Blin Université de Lorraine, Vandoeuvre les Nancy, France

Colloidal templating has been widely used to fabricate porous materials with different shapes and sizes ranging from several nm to several microns. Hierarchical macro–mesostructured silica has been successfully synthesized by the use of self-assembled templates of colloidal spheres such as polystyrene, poly(methyl methacrylate) latex spheres, silica spheres, and emulsion droplets. Silica is also known to be safe, not only for the environment, but also for the human body within a certain range of administrated dose. Therefore, its application field may be extended to biocompatible materials and, recently, for oral drug delivery. In the soft matter field, Solid Lipid Nanoparticles (SLN) appeared very recently as promising drug carriers especially for their potential applications in pharmaceutics. Therefore, combining inorganic silica matter with a solid lipid, SLN appears as a straightforward approach for the development of novel hybrid organic–inorganic biocompatible materials. Herein we present the first examples of solid lipid nanoparticles (SLN) templating silica reported in the literature (1). The resulting material has spherical pores, imprinting from the starting SLN and a mesoporous shell formed by the self-assembling mechanism of micellar solutions used as stabilizer of lipid nanoparticles. The morphology of the final material depending of the reaction conditions (temperature, reaction time, surfactant/silica source ratio) will also be discussed. Loading and release studies of an anticancer agent will be also presented. (1) [1] Andreea Pasc, Jean-Luc Blin, Marie-José Stébé, Jaafar Ghanbaja RSC Advances 2011, 1, 1204-1206.

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Multifunctional nanogels as building blocks for nanostructured materials Andrij Pich 1; Dominic Kehren 2; Sebastian Berger 3 1RWTH Aachen University, Macromolecular Chemistry, Aachen, Germany; 2RWTH Aachen University, Aachen, Germany; 3BASF, Ludwigshafen, Germany

Synthesis of aqueous nanogel particles can be performed in controlled way to tune particle size and size distribution, chemical functionality, surface charge, swelling degree, colloidal stability and stimuli-sensitivity. The post-modification reactions provide a tool-box for incorporation of small organic molecules, synthetic polymers, biopolymers or inorganic nanoparticles into colloidal nanogel network thus leading to the formation of multifunctional colloids. Such colloids may exhibit electrical conductivity, magnetic response, optical and catalytic activity and can be used as building blocks for the preparation of well-ordered nanostructured materials of different dimensions and complexity. By controlled self-assembly of nanogels in solution, on interfaces or surfaces defined architectures like colloidosomes, fibers, networks, arrays or films can be obtained. In present paper we will present some examples for design of nanogel-based materials. We have developed a simple route for the preparation of the novel multi-sensitive nanogel-based capsules. The variation of the microgel and polymer properties as well as their concentration provides a control over important capsule parameters such as size, morphology, wall thickness, degradability etc. Nanogel- and nanogel/polymer-based composite microfibers can be prepared by electrospinning process. Obtained microfibers with tuneable dimensions, swelling behaviour and mechanical properties have been obtained by varying the nanogel properties (size and chemical structure), nanogel/polymer ratio and viscosity of spinning solution. The large scale self-assembly of nanogels using nanostructured substrates was investigated. Different behaviour for the microgel types arranged in grooves of wrinkles was observed concerning particle shape and pattern formation. Single particle lines as well as zigzag-structures were obtained. By using wrinkles as stamps in a printing approach nanogel arrays were transferred to planar substrates.

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Effect of chemical admixtures on the hydration kinetics of cementitious materials Francesca Ridi ; Emiliano Fratini ; Piero Baglioni University of Florence, Chemistry, Florence, Italy

Cement is the hydraulic binder responsible for the binding properties of concrete, the most abundant synthetic material in the world. It is a complex mixture of inorganic phases, composed by silicates, aluminates and alumino-ferrites. The great interest in this material stems from the fact that an easily workable mixture of low-cost raw materials transforms through a simple hydration reaction into a durable, hard, stone-like material. Both crystalline and amorphous products result from the hydration reaction. The amorphous phases, mainly calcium silicate hydrate (C-S-H), have a colloidal nature and give rise to the binding properties of cement. At the nanoscale, it consists of globular units. By self-aggregation these globules generate a fractal matrix, which is responsible for the mechanical properties of the cured paste. Controlling these processes in the presence of chemical admixtures is likely to be one of the key factors in the improvement of the final properties. Polycarboxylic polymers with polyethylene oxide side chains (PCE) are nowadays the most efficient class of superplasticizers, used to confer high fluidity and workability to the pastes with low water content. This work aimed to explore the influence of PCEs with well-known molecular structures on the hydration kinetics and on the morphology of C-S-H gel phase. The kinetic curves, followed by means of Differential Scanning Calorimetry (DSC), have been analyzed through the application of the Generalized Boundary Nucleation and Growth Model (G-BNGM), combined with a diffusional model to account for the last part of the kinetic: this approach allowed insights into the effect of the molecular architecture of the PCEs on the induction time, rate constants and diffusional constants. A combined approach by means of Low Temperature Differential Scanning Calorimetry (LT-DSC), Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) highlighted the influence of PCE on the development of the final microstructure. Moreover, these investigations will be discussed and correlated to Small Angle Neutron Scattering (SANS) measurements performed on pure C-S-H samples synthetized in the presence of PCEs.

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Hydration reaction of Portland cement in the presence of carbonate and a superplasticizer: influence of the temperature Francesca Ridi ; Fabiana Spadaro ; Piero Baglioni University of Florence (Italy), Chemistry, Florence, Italy

Calcium carbonate is one of the permitted inorganic fillers for Portland cement formulations. For a long time it has been considered as an inert component, but since ‘80s several studies have pointed out that calcium carbonate actively participate to the hydration reaction, and modifies the hydration products. Most of the studies on this topic are focused on the effect of the carbonate content and of its granulometry on the formation of the hydration products. Some evidences have pointed out that the mineralogy of cement pastes hydrated in the presence of calcium carbonate changes with temperature, and recently thermodynamic calculations have been reported as a tool to predict the development of paste mineralogy as a function of the temperature. Nevertheless, literature still lacks for specific and exhaustive experimental investigations at this regard. In this work we studied the influence of the temperature on a Portland limestone cement paste, in the range 10-40 °C. Moreover we investigated the effect of the addition of a polycarboxylic superplasticizer. Considering that almost every real formulation contains similar additives, understanding their influence on Portland limestone cements is likely to be decisive to control the final properties of the materials. A multiple approach based on thermal methods (Differential Scanning Calorimetry, Differential Thermogravimetry), spectroscopic methods (X-ray Diffraction, Infrared Spectroscopy) and microscopy (Scanning Electron Microscopy) characterized the systems in terms of kinetic behavior, mineralogy and microstructure development.

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Tackling complex nanomaterial with field-flow fractionation Lars Nilsson ; J. Ray Runyon Lund University, Food Technology, Engineering and Nutrition, Lund, Sweden

Nanoparticles come in a wide variety of chemistries, sizes, shapes, charges, surface chemistries and functionalities, optical and magnetic properties. Tailoring the function and/or application of nanomaterials requires manipulation of these properties in a controlled manner. Detailed knowledge of the nanomaterial physicochemical properties as a function of its inherent polydispersity is therefore needed. Teasing out subtleties that may exist between different sub-populations within an entire nanoparticle sample can be challenging. Field-flow fractionation (FFF) addresses this challenge through size-based fractionations of complex nanomaterials. FFF has been utilized to separate nanomaterials such as natural and engineered nanoparticles, synthetic and biological polymers, polysaccharides, proteins and protein aggregates, polyelectrolyte complexes, emulsions, whole cells, subcellular organelles, liposomes, viruses, supra-molecular assemblies and hybrid nanomaterial composites ranging in size from ~1 nm to ~50 µm. Sample fractionation occurs in an open ribbon-like channel devoid of packing material under low shear, laminar flow conditions which creates a gentle separation environment. An external force such as a fluid flow, centrifugal force, temperature gradient, electric field or magnetic field is applied perpendicular to the transport of the analyte through the channel. Differential interaction of the sample with the field results in retention and separation as a function of hydrodynamic size plus an additional physicochemical property, i.e., composition, density, effective mass, charge, etc. A cross flow of fluid is the predominately used field and asymmetric FFF (AF4) the most commonly utilized FFF technique. Combination of FFF retention time with detector data (UV-Vis, differential refractive index, light scattering) yields additional characterization of the nanomaterials with respect to branching, shape, topology, apparent density and aggregation state. This poster presents a broader perspective of FFF within the nanoscience and nanotechnology community. Examples of FFF separations and characterization of nanomaterials is shown and discussed.

318


Construction and expression of fluobody against Amphiphilic Saponin, Ginsenosides for Fluorescence-Linked Immunosorbent Assay Seiichi Sakamoto 1; Yusuke Tanizaki 2; Benyakan Pongkitwitoon 2; Osamu Shibata 1; Hirioyuki Tanaka 2; Satoshi Morimoto 2 1Faculty of Pharmaceutical Sciences, Nagasaki International University, Departmnet of Biophysical Chemistry, Sasebo, Japan; 2Graduate School of Pharmaceutical Sciences, Kyushu University, Department of Pharmacognosy, Fukuoka, Japan

Ginsenosides are well known as major bioactive saponins mainly produced in Panax ginseng (P. ginseng). Since the variety of total and individual ginsenoside concentration in the market products has been critical issue from the point of view of quality control, a method for standardizing ginseng samples is required. In this study, two chimera proteins of AcGFP fused at the C-terminus of GRe-scFv (C-fluobody) and N-terminus of GRe-scFv (N-fluobody) has been constructed, expressed, and characterized for the development of even more simple, speedy, and sensitive fluorescence-linked immunosorbent assay (FLISA) [Protein Expr. Purif., 77 (2011) 124]. Splicing by overlapped extension PCR (SOE-PCR) was carried out to for the construction of fluobodies. The recombinant fluobodies were expressed in E. coli BL21 (DE3) strain, purified by immobilized metal ion affinity chromatography, and refolded by stepwise dialysis. Characterization of fluobodies was carried out by measurement of fluorescence intensity, ELISA, and FLISA. In FLISA, it takes only 3 h to complete because the time-consuming enzyme-substrate reaction necessary for ELISA can be avoided. In the characterization of fluobodies based on fluorescence intensity, C-fluobody showed 600-fold higher than N-fluobody. Moreover, the limit of detection (LOD) for G-Re determination in FLISA using the C-fluobody (10 ng/mL) was found to be 10-fold lower than that in conventional ELISA (100 ng/mL). It is estimated that the improvement of LOD was derived from the highly sensitive fluorescence of AcGFP detected by the fluorescent microplate reader compared with that of the enzymatic chromophore. These results indicate that not only simple and speedy immunoassay but also a sensitive immunoassay could be developed by using C-fluobody instead of monoclonal antibody or scFv. These results supports our previous study noting that C-format fluobody is superior to N-format fluobody in FLISA [Anal. Bioanal. Chem., 396 (2010) 2955].

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Internally structured nanoparticles of surfactant ion-polyion complex salt and nonionic surfactant John Janiak 1; Karin Schillen 1; Solmaz Bayati 1; Viorel Pavel 2; Luciano Galantini 2 1Lund University, Division of Physical Chemistry, Lund, Sweden; 2Sapienza University of Rome, Department of Chemistry, Rome, Italy

Nanoparticles with an internal structure (bicontinuous cubic or hexagonal) have been found in a surfactant ion-polyion complex salt system. They were formed by dispersing poly(acrylic acid) of polymerization degree of 6000 (PAA6000) together with the cationic surfactant C16TAOH and the nonionic surfactant C12E5 in water at different mixing ratios in the corresponding two-phase regions (liquid crystalline phase/dilute phase) of the ternary phase diagram C16TAPA6000 complex salt/C12E5/water, see the reference. According to dynamic light scattering and electrophoretic mobility measurements, the particles have a well-defined size (about 150 nm) and a positive net-charge. Synchrotron small angle X-ray scattering measurements confirm the cubic or the hexagonal ordering and the structured nanoparticles are visualized by cryogenic transmission electron microscopy. Reference: Janiak, J.; Piculell, L.; Olofsson, G.; Schillén, K. Phys. Chem. Chem. Phys. 2011, 13, 3126.

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Preparation and thermal stability of fluorinated sulfonic acid derivatives/silica nanocomposites Saki Souma 1; Mieko Kikuchi 1; Shun Kodama 2; Masashi Sugiya 2; Hideo Sawada 1 1Hirosaki University, Hirosaki, Japan; 2Nippon Chemical Industrial Co., Ltd., Tokyo, Japan

We have recently prepared fluoroalkyl end-capped sulfonic acid oligomer/silica nanocomposites through the sol-gel reactions of the corresponding oligomer with tetraethoxysilane [TEOS] and silica nanoparticles under alkaline conditions. [1] These nanocomposites can afford no weight loss behavior corresponding to the contents of the oligomer to exhibit a nonflammable characteristic even after calcinations at 800 °C. [1] Low molecular weight fluorinated surfactants possessing sulfo groups such as perfluoro-1, 3-propanedisulfonic acid [PFPS] were also applied to the preparation of PFPS/silica nanocomposites possessing a nonflammable characteristic. [2] Here we report the preparation of fluorinated sulfonic acid derivatives such as NafionTR/silica nanocomposites. Nafion/silica nanocomposites can be prepared by the sol-gel reactions of Nafion with silica nanoparticles and TEOS under alkaline conditions. We also prepared Nafion/PFPS/silica nanocomposites by the sol-gel reactions under similar conditions. Nafion/silica nanocomposites exhibited a clear weight loss behavior corresponding to the contents of Nafion in the composites after calcination; however, interestingly, Nafion/PFPS/silica nanocomposites were found to exhibit no weight loss behavior even after calcination. [1] H. Sawada, T. Tashima et al., Polym. J., 2010, 42, 167. [2] H. Sawada, X. Liu, Y. Goto, M. Kikuchi et al., J. Colloid Interface Sci., 2011, 356, 8.

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Controlling photochromism between fluoroalkyl end-capped oligomer/polyaniline and /N,N’-diphenyl-1,4-phenylenediamine nanocomposites induced by UV-light-responsive titanium oxide nanoparticles Taiki Tsuzuki-ishi 1; Tetsushi Kijima 1; Mari Iizuka 2; Masato Yoshida 2; Hideo Sawada 1 1Hirosaki University, Hirosaki, Japan; 2Shimane University, Izumo, Japan

Fluoroalkyl end-capped oligomers/titanium oxide nanocomposites have been recently applied to the surface modification of glass to exhibit not only a completely superhydrophobic characteristic with a non-wetting property against water droplets but also a good oleophobicity imparted by fluoroalkyl segments in the composites on their surface.[1] Therefore, it is in particular interest to develop novel fluoroalkyl end-capped oligomers/polyaniline (PAn)/titanium oxide nanoparticle composites, because these fluorinated composites have high potential applications imparted by not only fluorine but also PAn or titanium oxide toward a variety of areas such as conductive coating, charge storage, electrocatalyst, electrochromic devices, and photovoltaic cells.[2] Here we report that PAn and phenyl-capped aniline dimer (An-dimer: N,N’-diphenyl-1,4-phenylenediamine), which is considered to be an excellent model of PAn, are applied to the efficient preparation of fluorinated oligomer/PAn/titanium oxide nanocomposites and /An-dimer/titanium oxide nanocomposites by the use of the corresponding oligomer/PAn and /An-dimer nanocomposites, with a particular emphasis on the evaluation of controlled photochromic behaviors between fluorinated PAn/titanium oxide and An-dimer/titanium oxide nanocomposites. [1] H. Sawada, Polym. Chem. 2012, 3, 46. [2] M. R. Hoffmann, S. T. Martin, D. W. Bahnemann, Chem. Rev. 1995, 95, 69.

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CdSe quantum dots encapsulated in polymeric micelles Kazimiera A. Wilk 1; Renata Frackowiak 1; Marcin Nyk 2; Marek Samoc 2 1Wroclaw University of Technology, Organic and Pharmaceutical Technology Group, Faculty of Chemistry, Wroclaw, Poland; 2Wroclaw University of Technology, Institute of Physical and Theoretical Chemistry, Wroclaw, Poland

Polymeric micelles (PMs) are promising nanocarriers for drug delivery, diagnostics or other biomedical applications. By loading such nanocarriers with therapeutic or diagnostics species one can eliminate the problems of poor solubility of such species and can attain favorable traits such as nontoxicity and biocompatibility. Encapsulated therapeutic molecules can be protected from the biological environment and their bioavailability and biodistribution can be enhanced while the nanocarriers can also provide additional functionalities, e.g., multimodal imaging through the cargo of suitable labels such as highly luminescent species capable of being imaged through nonlinear optical techniques. To evaluate the feasibility of the PMs to carry multifunctional loads we studied the suitability of Pluronic P123 carriers to protect and solubilize hydrophobic CdSe QDs which can be employed for nonlinear absorption and energy transfer to therapeutic species [1]. This work folows on our recent studies of fabrication and evaluation of new polymeric nanocarriers [2]. The systems were fabricated through hydrating of thin films. Their size and polydispersity were characterized by DLS, morphology was assessed by AFM and TEM and good colloidal stability of encapsulated QDs was proved by studying absorbance vs time. Fluorescence lifetimes were obtained by time-correlated single photon counting with excitation with 1.2 ns pulses at 460 nm. The results were compared with raw CdSe QDs in toluene that exhibited single exponential =20 ns. The decays for CdSe in nanocarriers were non-exponentialτdecay with suggesting partial energy transfer between CdSe QDs and hydrophilic part of PMs. 1. M. Nyk, K. Palewska, L. Kêpiñski, K. A. Wilk, W, Strêk, M. Samoæ, J. Lumin. 130 (2010) 2487. 2. U. Bazyliñska, R. Skrzela, K. Szczepanowicz, P. Warszyñski, K. A. Wilk, Soft Matter 7(2011) 6113; J. Pietkiewicz, K. Zieliñska, J. Saczko, J. Kulbacka, M. Majkowski, K. A. Wilk, Eur. J. Pharm. Sci. 39 (2010) 322.

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Modification of wrinkled surfaces through defects and their application for nanostructures of soft matter particles Patrick Wuennemann ; Marco Phillipp Schuerings ; Felix Plamper ; Andrij Pich ; Alexander Boeker RWTH Aachen, Aachen, Germany

We verify the effects of implied defects on soft Poly(dimethylsiloxane) (PDMS) substrates through the formation of wrinkle structures to develop new patterns of wrinkled surfaces. These stress induced disruptions lead to star-like wrinkled SiO2-sufaces in nanoscale. Next to the effects of single defects we investigate wrinkled structures in the area between adjacent defects. First description of the domains, the wavelength and the induced pattern near the nanodefects are characterized by atomic force microscopy (SFM). The focus of our work is the correlation between wavelength and thickness of the silanized PDMS-surface and the applied strain. Compared to other systems these defects aren’t fabricated by lithographic methods and can be produced over large areas in short time. We further study the possible use as a template for the one- and two-dimensional arrangement of soft matter particles (e.g. N-vinyl-caprolactam/Acetoacetoxy ethylmethacrylate-microgels (VCL/AAEM)).

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Ion-based organic dye nanoparticles with versatile fluorescence colour tunability: efficient antenna effect Hiroshi Yao ; Koji Ashiba University of Hyogo, Hyogo, Japan

Organic nanoparticles consisting of 3,3’-diethylthiacyanine (TC) and ethidium (ED) dyes are synthesized via ion-association between the cationic dye mixture of 10% ED and tetrakis(4-fluorophenyl)borate (TFPB) anion, in the presence of neutral stabilizing polymer, in aqueous solution. This method utilizes formation of water-insoluble ion-pair solids in aqueous phases by electrostatic association of chromophoric cations with a hydrophobic counteranion such as TFPB. Doping of ED makes the particle size smaller than that without doping. Size tuning can be also conducted by varying the molar ratio (= r) of the loaded anion to the cationic dyes. Fluorescence spectrum of TC shows good overlap with the absorption of ED in the 450–600 nm wavelength region, so efficient excitation energy transfer from TC (donor) to ED (acceptor) is observed, yielding organic nanoparticles with tunable fluorescence colour. Upon ED doping, the emission colour significantly changes from greenish-blue to reddish or whitish, which is mainly dependent on r. For the doped nanoparticle sample with r = 1, the intensity of fluorescence ascribed to ED is ~150-fold higher than that from pure ED nanoparticles (efficient antenna effect). Non-radiative Förster resonance energy transfer (FRET) is the dominant mechanism for the ED fluorescence enhancement. We believe the doped organic nanoparticles fabricated using the present method can act as efficient light-harvesting antennae capable of transferring light energy to the dopant acceptors which are in very close proximity to donors, resulting in multi-wavelength emission colour with high quantum yields.

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Interaction of donepezil and human serum albumin on amine-modified magnetic nanoparticles Leman Buzoglu ; Esra Maltas ; Mustafa Ozmen ; Salih Yildiz University of Selcuk, Department of Chemistry, Konya, Turkey

Nanoparticles which can be directed by external magnetic field from have a large range of usage in many studies such as controlled drug release, bioseparation, cell isolation, hyperthermia, magnetic resonance imaging, gen transfection and tissue engineering, protein and DNA immobilization [1-3]. In this work, the interaction between drug (donepezil) and human serum albumin was evaluated on the surface of amine modified magnetic nanoparticles (MNPs) which were synthesized by the coprecipitation of ferrous and ferric salts with ammonia, and then modified with [3-Aminopropyl] triethoxy silane (APTES) to obtain functional amine groups on nanoparticles surface [1-2]. Binding capacity of albumin to APTES-MNPs was estimated by fluorescence spectroscopy. Albumin has the intrinsic fluorescence at 280 and 324 nm of excitation and emission wavelengths related to tyrosine and tryptophan residues [4]. After binding of HSA to APTES-MNPs, donepezil was interacted with HSA bounded APTES-MNPs in 50 mM phosphate saline buffer (PBS, pH: 7.4). Binding capacity of the drug was determined using calibration curve equation which was drawn by fluorescence spectroscopy at 280 and 324 nm of excitation and emission wavelengths. Binding of HSA and donepezil to amine modified MNPs were also examined by IR and SEM. References: 1. A. Ito, M. Shinkai, H. Honda, T. Kobayashi, “Medical application of functionalized magnetic nanoparticles”, J. Biosci. Bioengineer., 100, 2005, 1. 2. A.K. Gupta, M. Gupta, “Synthesis and surface engineering of iron oxide nanoparticles for biomedical applications”, Biomaterials, 26, 2005, 3995-4021. 3. Y.J. Hu, Y. Liu, X.S. Shen, X.Y. Fang, S.S. Qu, “Studies on the interaction between 1-hexylcarbamoyl-5- fluorouracil and bovine serum albumin”, J. Mol. Struc. 738, 2005, 143–147. 4. B. Shuyun, S. Yantao, Q. Chunyu, Z. Hanqi, L. Chunming, “Binding of several anti-tumor drugs to bovine serum albumin: Fluorescence study”, J. Luminescence, 129, 2009, 541–547.

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Controlled deposit of polymer nanoparticles onto a conductive solid substrate and its functionalization by a protein Damien Bazin 1; Sébastien Chevalier 2; Hélène Feracci 1; Chantal Larpent 3; Hassan Saadaoui 1; Chrystel Faure 4 1CNRS, Pessac, France; 2CNRS, Toulouse, France; 3Université de Versailles, Versailles, France; 4Université de Bordeaux, Pessac, France

Bio-functional surfaces are very useful for cell-based assays, biosensors, bioelectronics and medical devices.[1] Ideal bio-functional surfaces should be biocompatible, efficient, easy to prepare and cheap. We developed an innovative and easy method for the preparation of ordered and non-ordered bio-functional surfaces based on the controlled and fast electro-deposit of polymer nanoparticles (nps) for protein immobilization.[2,3] It consists in depositing bio-functionalizable polymer nanoparticles (cyclam-nps) onto a conductive substrate (Indium Tin Oxide (ITO) electrode) from an aqueous dispersion of cyclam-nps submitted to a Direct Current (DC) electric field.[3] These nps can be uniformly deposited onto the electrode with a controlled density, or be deposited as hexagonal arrays of patches using a technique we developed called electro-colloidal lithography.[2] The density of deposited nps measured by AFM is shown to be correlated to the concentration of nps into the dispersion and deposition takes less than 5 seconds. The nps being functionalized with metal ion-chelating groups (cyclam-groups), they can be used as anchoring sites for 6-Histidine (6-His) tagged proteins through divalent metal ions.[4] Here, 6-His Green Fluorescent Protein (6-His GFP) is used as a model protein. The characterization by fluorescent microscopy clearly shows that the protein affinity was ion dependent and that the 6-His GFP density can be controlled by np density, which is itself easily tunable. AFM observations confirmed the immobilization of 6-His GFP onto cyclam-nps and its removal by EDTA treatment. 1. Wong, L.S. et al., Chemical Reviews, 2009. 109: p. 4025 2. Bazin, D. et al., Soft matter, 2012, 8, 3053 3. Bazin, D. et al., submitted to Langmuir 4. Chevalier, S. et al. Langmuir, 2010. 26: p. 14707

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Molecular mobility of the skin barrier by polarization transfer solid-state NMR Sebastian Bjorklund ; Agnieszka Nowacka ; Emma Sparr ; Daniel Topgaard Division of Physical Chemistry, Institution of Chemistry, Lund University, Lund, Sweden

The mammalian skin barrier, known as the stratum corneum (SC), is located in the outermost layer of the skin and represents a complex colloidal biomembrane. It consists of dead and anucleated epidermal cells (corneocytes) that are filled with mainly keratin filaments. The corneocytes are embedded in a continuous multilamellar lipid matrix. The SC membrane separates environments that are profoundly different, and it can be exposed to rather extreme variations in hydration, temperature, as well as other species that can affect its structure and function. The so-called "occlusion effect" utilizes elevated hydration levels to enhance the SC permeability towards drugs. Despite the enormous potential for pharmaceutical applications, the molecular details of the changes in the SC associated with high permeability remain unknown. We investigate intact porcine SC using natural abundance 13C polarization-transfer solid-state NMR. After performing detailed 13C peak assignment, we study the influence of hydration and temperature on the dynamics of the SC molecular constituents. The majority of the lipids are solid at physiological temperature (32 °C), and those lipids co-exist with a smaller fraction of fluid lipids, which increases modestly upon hydration and dramatically with heating. There is an abrupt change in dynamics of the keratin filaments at RH = 80-85 %, with a transition from completely solid keratin to a structure with solid backbone and mobile protruding terminal domains. The present data together with our previous analysis of diffusional transport in SC membranes, can provide a molecular explanation for the so-called "occlusion effect" in skin.

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Ultrathin membranes from polymer-protein conjugates: from self-assembly to membrane performance Alexander Böker 1; Patrick van Rijn 1; Murat Tutus 2; Matthias Wessling 2 1RWTH Aachen, Lehrstuhl für Makromolekulare Materialien und Oberflächen, Aachen, Germany; 2RWTH Aachen, Lehrstuhl für Chemische Verfahrenstechnik, Aachen, Germany

Polymer-protein conjugates have been prepared form Horse spleen Ferritin (HSF) as a scaffold by grafting of thermo-responsive poly(N-isopropyl acrylamide) (PNIPAAm) and photo-cross-linkable (2-(dimethyl maleinimido)-N-ethyl-acrylamide (DMIAAm) from the 72 amino-groups on the exterior of HSF.[1] Pendant drop tensiometer measurements indicate that the particles are highly surface active, much more than the individual components alone. Thus, these novel bionanoparticles-polymer hybrids are excellent candidates for the stabilization of polar/apolar interfaces and in combination with photo-crosslinking 2-D membranes or semi-permeable capsules are synthesized.[2] Oil-in-water and water-in-oil Pickering emulsions have been prepared and stabilized by cross-linking, yielding soft capsules which are stable enough to be collected, transferred and are able to endure co-solvents like ethanol.[1,2] A similar procedure at flat fluid interfaces gives ultrathin and highly flexible membranes, which were characterized with respect to their flux and size exclusion properties, showing their high potential for membrane applications. [1] N. C. Mougin, P. van Rijn, H. Park, A.H.E. Müller, A. Böker, Adv. Funct. Mater., 2011, 21, 2470; [2] P. van Rijn, N.C. Mougin, D. Franke, H. Park and A. Böker, Chem. Commun., 2011, 47, 8376.

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Aptamer-based colorimetric detection of platelet-derived growth factor using unmodified gold nanoparticles Chia-Chen Chang 1; Shih-Chung Wei 2; Chung-Han Lee 1; Chii-Wann Lin 1 1National Taiwan University, Institute of Biomedical Engineering, Taipei, Taiwan; 2National Taiwan University, Institute of Biomedical Electronic and Bioinformatics, Taipei, Taiwan

The combination of DNA aptamer and gold nanoparticles (AuNPs) has been widely employed for biomedical analysis. Because this assay can provide a convenient naked eye colorimetric detection of protein, it is attracting considerable attention. The unmodified AuNP-based sensors do not require extra ligand preparation procedures, thus effectively distinguishing target-bound DNA from free aptamers. However, several DNA aptamers with unique secondary structures or longer lengths can not electrostatically stabilize AuNPs so they are unsuitable for the unmodified AuNP probes. An alternative route for these structured aptamers is the use of aptamer-linked AuNPs. For example, platelet-derived growth factor (PDGF) is known to regulate cell growth and division. There have been only a few reports on nanoparticle-based sensors due to the secondary loop structure of its aptamer. These approaches involve either the conjugation of the aptamer on AuNPs or the use of an aptamer-VAuNPs complex as part of the fluorescent sensing element. Nevertheless, these approaches suffer from a labor-intensive and time-consuming probe synthesis process. The ability to simple and rapid detect PDGF is a challenge that will require the conjugation of thiolated aptamer onto the AuNP surface. Herein, we report a simple but effective colorimetric detection using target-mediated base stacking hybridization to develop the alternative strategy without aptamer labeling for PDGF. The detection mechanism is based on the fact that the aptamer DNA can hybridize readily with the probe DNA in the presence of target due to the enhancement of base stacking. Thus, the probe DNA will not adsorb on AuNPs, resulting in the salt-induced aggregation for simple protein detection. The proposed method could detect PDGF with a linear range of 5 nM to 100 nM and a detection limit down to 5 nM. With its high sensitivity and simplified assay steps, this strategy could be extended for other structured aptamer-based sensing applications.

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Effects of adjuvants on tebuconazole leaf cuticle penetration Anton Fagerström 1; Vitaly Kocherbitov 1; Tautgirdas Ruzgas 1; Peter Westbye 2; Karin Bergström 2; Johan Engblom 3 1Malmö University, Biomedical Science, Faculty of Health and Society, Malmö, Sweden; 2AkzoNobel Surface Chemistry AB, Agro Applications Europe, Stenungsund, Sweden; 3Malmö University, Biomedical Science, Malmö, Sweden

In this study the effect of two adjuvants, C10EO7 and C8G1.6 on transcuticular uptake in plant leaves of the fungicide tebuconazole has been investigated. The mechanisms of solute permeation are described employing Fick’s first law of diffusion in its generalized form. In vitro diffusion methodology (Franz cells) using the ad axial side of leaves from the plant Clivia Miniata Regel and silicone sheeting as membranes is combined with sorption isotherms for tebuconazole on the two types of membrane. The performance of alternative carrier formulations with fixed solute chemical potential and fixed solute concentration are compared, and a novel algorithm has been developed to accommodate inevitable changes in boundary conditions. The results are clear and the same quantitative increase in both flux, and diffusion coefficient can be observed, while the cuticle-water partition coefficient remains unchanged. Moreover a decrease in permeation lag time (from 50 to about 20 h) is evident in the presence of surfactants. Furthermore it is shown that dermatomed ad axial Clivia leaves may replace enzymatically separated cuticles for evaluating in vitro permeability of solutes.

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Membrane interaction of α-synuclein in different aggregation states Marie Grey 1; Sara Linse 2; Patrik Brundin 3; Emma Sparr 1 1Fysikalisk kemi, Lunds Universitet, Lund, Sweden; 2Biofysikalisk kemi, Lunds Universitet, Lund, Sweden; 3Nervcellsöverlevnad, Lunds Universitet, Lund, Sweden

Aggregated α-synuclein in Lewy bodies and Lewy neurites are hallmarks of Parkinson’s disease (PD). Recent observations that aggregated α-synuclein is propagated to healthy neurons grafted into brains of PD patients prompted our study. We asked whether any, and if so which, molecular form(s) of α-synuclein can pass over model phospholipid bilayers. Confocal fluorescence microscopy was used to study the binding of Alexa488 labeled α-synuclein to giant unilamellar vesicles (GUVs) and to monitor if the α-synuclein is transported over the phospholipid bilayers. The GUVs were composed of mixtures of DOPC and DOPS or DOPC and cardiolipin at different molar ratios to vary the membrane charge. All lipids chosen for this study are common in human membranes. Cardiolipin is primarily found in the mitochondrion, i.e. an organelle that is implicated in PD pathogenesis. We studied membrane binding and transport for monomeric, fibrillar as well as on-pathway α-synuclein samples. To enable preparation of samples representing defined time points during the aggregation lag period, conditions were identified that resulted in reproducible aggregation kinetics at moderate shaking and at quiescent conditions. We observed association to lipid membranes for on-pathway species and equilibrium aggregates, but not for monomers. Particularly strong association was found between α-synuclein and GUVs that contained cardiolipin or DOPS. By contrast, α-synuclein did not associate with GUVs containing DOPC only. No transport of α-synuclein over the GUV bilayer was observed under any of the conditions studied. Labeled α-synuclein was never observed inside the GUVs although clearly visible in the surrounding buffer. This suggests that the transport of α-synuclein over membranes, which has been observed in several previously published cell culture experiments, requires additional molecular components and/or an active transport mechanism.

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Formulation and structural characterization of o/w nanoemulsions as effective carriers of bioactive compounds Aristotelis Xenakis 1; Vassiliki Papadimitriou 2; Argyro Kalaitzaki 2 1Orebro University, MTM Research Center, School of Science and Technology, Orebro, Sweden; 2National Hellenic Research Foundation, Institute of Biology, Pharmaceutical Chemistry & Biotechnology, Athens, Greece

Interest in nanoemulsions was developed recently, as direct applications in consumer products are being developed, in pharmacy and cosmetics but also in the food and beverage industries for certain applications. This happens because of their unique physicochemical and functional properties: high encapsulation efficiency, low turbidity, high bioavailability and high physical stability. The present study was focused on developments of nanoemulsions as final application products and on the optimization of their preparation. More specifically, the objective was the preparation of oil-in-water (O/W) thermodynamically stable nanoemulsion systems having a large interfacial area and solubilization capacity. The components that were used are safe and biocompatible materials. Initially, different systems were developed consisting of natural oils (R(+)-Limonene), non-ionic surfactants or mixtures of them (Tween 20, Tween 40, Tween 40:Tween 20 (1:1), Tween 40:Tween 20 (2:1)), distilled water and propylene glycol. The phase behavior of these systems was described by pseudo-ternary phase diagrams, which were determined at 25 °C. Phase transitions were detected visually by the appearance of cloudiness or sharply defined separated phases. Formulation of U-type, fully dilutable with aqueous phase nanoemulsuions is reported. Furthermore, from the applied research perspective, structural characterization of the proposed nanoemulsion systems is of great importance. In this respect various techniques, such as EPR spectroscopy (Electron Paramagnetic Resonance), Dynamic light scattering, and electrical conductivity were carried out to characterize the nanoemulsion formulations. Having a formulated nanoemulsion, various substances with biological activity can be incorporated either by adding them gradually with the aqueous phase or by mixing them initially with the oil phase. Of particular interest is the incorporation of lipophilic compounds such as drugs, flavors. The use of o/w nanoemulsions is foreseen as an effective carrier to overcome the solubility limitations. For this, the system should be biocompatible and owe a diluting capacity against water.

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Characterisation of biosurfactants for industrial applications Ishara Kamalanathan ; Denny Vitasari ; Paul Grassia ; Robin Curtis ; Peter Martin University of Manchester, Manchester, United Kingdom

The majority of demand for surfactants is currently met by petrochemical and oleochemical surfactants. While petrochemical surfactants pose a threat to the environment due to bioaccumulation and aquatic toxicity, olechemical surfactants produced from vegetable or animal fats require expensive farm lands. Biosurfactants are microbially produced surfactants broadly classed into six groups (glycolipids, lipids, hydrophobin proteins, lipopeptides, polymers and particulates) depending on their chemical structure, microbial origin and molecular weight. They have many advantages in particular, biosurfactants may be produced using a variety of substrates, are biocompatible with low toxicity, are more sustainable than conventional surfactants and have a wide diversity allowing for greater surfactant functionality. Determining physiochemical properties of biosurfactants and their interfacial behaviour is needed to evaluate the performance and suitability of biosurfactants for various industrial applications. This paper presents the results of a comparative study of the equilibrium and dynamic surface properties of a pentaethylene glycol monododecyl ether C12E5(a 0.406 kDa non-ionic synthetic surfactant), with the biosurfactant surfactin (a 1.04 kDa cyclic lipopeptide) and BSA (a 66 kDa protein). Wilhelmy plate, pendant drop, maximum bubble pressure, dynamic light scattering and Langmuir trough experiments have been used to determine the critical micelle concentration, equilibrium and dynamic surface tension and monolayer characteristics. Surfactin is found to have a lower CMC and equilibrium surface tensions than BSA or C12E5. For mixtures of BSA with either surfactin or C12E5, competitive adsorption and displacement of BSA has been observed. The extent of displacement depends on the concentration and type of surfactant present in the mixture. A numerical simulation for one dimensional adsorption based on the Ward-Tordai equation was used for predicting and fitting the diffusion/adsorption behaviour of single and two component systems. This analysis provides a better understanding for engineering dynamic adsorption in process and product applications.

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Protein adsorption to hydrophobic nanospheres Sebastian Kapp 1; Marina Kasimova 2; Iben Larsson 3; Marco van de Weert 1; Lene Jorgensen 1 1University of Copenhagen, Department of Pharmacy, Copenhagen O, Denmark; 2Protein solutions, Copenhagen, Denmark; 3Amgros, copenhagen, Denmark

Objective: To gain insight into the mechanisms controlling adsorption, three proteins (beta-casein, alpha synuclein, growth hormone) were studied by isothermal titration calorimetry (ITC) in terms of their adsorption behavior onto modified hydrophobic polystyrene beads. Method: Peptide solutions were titrated into the beads in the temperature range from 10 to 47°C. Preliminary results: The interaction between protein and surface is exothermic and occurs in spite of the fact that at pH 7.4 both are negatively charged. The enthalpy of adsorption becomes more favorable with increasing temperature, indicating a negative heat capacity. The association constant, K, is in a 1/µM range, indicating strong binding. The Gibbs free energy of binding for beta-casein and growth hormone seem to be independent of temperature, while for alpha-synuclein this parameter increases in absolute value with increasing temperature. Preliminary conclusion: The process seems to be driven by hydrophobic interactions.

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Saliva adsorption onto different materials studied by QCM-D Liselott Lindh ; Alejandro Barrantes ; Thomas Arnebrant Malmoe University, Malmoe, Sweden

Salivary films form on all types of surfaces present intra-orally. These films exhibit functions as e.g. protective barriers, keeping hydration and lubricating present surfaces. The formation of salivary films on different surfaces has been followed by means of quartz crystal microbalance with dissipation (QCM-D). By fitting the values obtained using the Voigt [1] model to the changes in frequency and dissipation measured, it has been possible to calculate the thickness of the formed films and their viscoelastic properties, shear elastic modulus (µ) and shear viscosity (η). Here we present results for both saliva, HWS, and filter sterilized saliva, sHWS, on surfaces with different chemical composition relevant for oral surfaces and dental materials. There are clear differences in the film forming properties of the saliva preparations, for example, the values obtained for µ for HWS films are more sensitive to surface properties than those formed from sHWS. This is discussed in relation to differences in protein composition between the two types of saliva studied by SDS-PAGE. From the latter results it is clear that high molecular weight proteins are present in lower amounts in the sterile filtered saliva compared to saliva. [1] Viscoelastic Acoustic Response of Layered Polymer Films at Fluid-Solid Interfaces: Continuum Mechanics Approach. M.V. Voinova, M. Rodahl, M. Jonson, and B. Kasemo. Physica Scripta (1999) 59, 391-396

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Immobilization of biomolecules for biosensing application Antonia Mallardi 1; Mauro Giustini 2; Luisa Torsi 3; Gerardo Palazzo 3 1CNR - IPCF, Istituto per i Processi Chimico-Fisici, Bari, Italy; 2Dip. di Chimica, Università “La sapienza” di Roma, Roma, Italy; 3Dip. di Chimica, Università di Bari, Bari, Italy

Biosensors are analytical devices incorporating a biological material intimately associated with a transducer. The method of biomolecules immobilization is one of the key concerns in the fabrication of biosensors. Here, an overview will be presented on the immobilization strategies of proteins and biomolecules in biosensors, with applications in optical and electronic devices. A convenient method for protein immobilization is the electrostatic layer-by-layer (LbL) technique. We have immobilized both water soluble proteins and detergent solubilized membrane proteins, obtaining very good results in terms of stability and reusability of biomolecules. The obtained multilayers have successfully been employed in optical sensing devices for herbicide and phenolic compound determination (1). Electronic biosensors can open new perspectives in terms of several still open issues: low manufacturing cost, light weight, miniaturization/portability and flexibility. In particular, organic field-effect transistors (OFET) based biosensors have recently been identified to meet these requirements. In our research novel immobilization protocols are developed in order to integrate bio-probes directly within the OFET structure. Bio-probes have been immobilized on the sensors surface using both conventional procedures and more innovative strategies. The coupling of the OFET device and the biological recognition system is actuated by assembling supra-molecular structures in which biomolecules such as phospholipids and proteins are fully integrated in the electronic device. After integration into the OFET both electronic performance and biomolecule functionality are retained. Successful results have been obtained with the immobilization of bacteriorhopsin protein: the obtained device has been proposed as biosensor for anesthetic detection. Furthermore, a streptavidin embedding OFET shows label-free biotin electronic detection at 10 parts-per-trillion concentration level, reaching state-of-the-art fluorescent assay performances (2). (1) M. Giustini et al. Sensors and Actuators B 163 (2012) 69 – 75 (2) M.D. Angione et al. PNAS (2012) doi:10.1073/pnas.1200549109

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Behaviour of oil bodies under processing conditions Sania Maurer ; Gustav Waschatko ; Birgitta Schiedt ; Thomas A. Vilgis Max Planck Institute for Polymer Research, Mainz, Germany

Diverse plant species store neutral lipids (triacylglycerides (TAGs)) in seeds as nutritional reserve for germination and growth. TAGs are present in the matrix of small subcellular spherical oil bodies (OBs) surrounded by a monolayer of phospholipids (PLs) and proteins. The molecular structure of proteins termed as oleosins is mainly responsible for the remarkable stabilisation of OBs against aggregation or coalescence. Their central hydrophobic stretch is anchored hairpin-like in the oil-phase consisting of the longest sequence of hydrophobic amino acids known in nature (1). The hydrophilic N- and C-terminal domains completely cover the OBs surface. Due to their unique composition, isolated OBs of 350 nm average hydrodynamic diameter provide an excellent natural emulsifier and encapsulation system. The specific interfacial properties and relatively good stability against environmental and processing conditions (2) make OBs valuable for cosmetic, pharmaceutical and food applications. By applying common processing techniques, the stability, structural modifications, interfacial activity and interactions with other components under manufacturing conditions are investigated to reveal the potential of OBs for application as a functional additive. As a broad range of additives is transformed into powder, the effect of different drying conditions during spray drying on structural modifications and on the adsorption kinetics at the air-water interface of the OBs are investigated. Reconstitution tests of dried OBs will help to evaluate the general impact of spray drying on OBs, particularly with regard to the adsorption behaviour at oil-water interfaces being e.g., relevant for o/w emulsions of high oil content. (1) Hsieh, K., and Huang, A. H. C., (2004). Plant Physiol., 136, 3427-3434. (2) Iwanaga, D. et al., (2007). J. Agric. Food. Chem., 55, 8711-8715.

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Modelling the kinetics of Nanoparticles interacting with plasma proteins Silvia Milani 1; Anna Salvati 2; Marco Monopoli 2; Francesca Baldelli Bombelli 3; Kenneth Dawson 2; Joachim Raedler 1 1Ludwig-Maximilians-Universität, LMU, Faculty of Physics, Munich, Germany; 2University College Dublin, Centre for BioNano Interactions, School of Chemistry and Chemical Biology, Dublin, Ireland; 3University of East Anglia, School of Pharmacy, Norwich, United Kingdom

The study of the nano-bio interface has so far obtained important breakthroughs. Indeed, it is now well established that in a biological fluid, the surface of nanoparticles is immediately modified by the adsorption of proteins, or other biomolecules, leading to the formation of a “protein corona”. This shell of biomolecules defines the real physicochemical properties of the nanoparticles: it determines the nanoparticles stability, and drives the uptake into the cells. Yet despite its role a comprehensive knowledge of the binding mechanisms and of the dependence of the protein corona on nanomaterial properties is still incomplete. Here we use fluorescence correlation spectroscopy (FCS) to shed light on the binding dynamics of plasma proteins on the nanoparticle surface. We find the existence of two distinct time scale dynamics in the protein off-kinetics. We show for the first time that there are two layers of biomolecules bound to the nanoparticles. The first layer is irreversibly bound, and therefore biologically relevant, whereas the second is weakly bound and easily exchange with competitive proteins in solution. This finding implies that the order of protein exposure leaves behind a pattern of irreversibly bound proteins, which provides NPs with a unique fingerprint or “memory function”, which eventually will define the biological identity of the nanoparticles.

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Surface and viscous properties of gelatin/Na caseinate mixtures Jadranka Milanovic ; Verica Sovilj ; Lidija Petrovic University of Novi Sad Faculty of Technology, Novi Sad, Serbia

Gelatin is a protein widely used in food, pharmaceutical and cosmetic products as an emulsifier, peptizer, thickener, and binder. Polypeptide structure of gelatin molecule facilitates its interactions with other oppositely charged ingredients often present in such products. Sodium caseinate (NaCN) due to its excellent functional and nutritional properties, is also very often used as a hydophilic emulsifier in a wide range of dispersed systems together with other proteins, as gelatin. Since NaCN is a polyelectrolyte different type of interactions in such systems can occur. These interactions can significantly change properties of gelatin solution in the bulk as well as on the interface, and therefore influence the stability of the systems. The aim of this study was to investigate surface and viscous properties of gelatin A in presence of various concentrations of NaCN. For that purpose digital tensiometer KSV Sigma 703D, Cannon capillary viscosimeter and rheometer Haake RS600 were used. Surface tension and relative viscosity were measured at 40°C and expressed as a function of NaCN concentration, while concentrations of gelatin were kept constant at 0.5; 1 and 2%. From these investigations mixtures of 1% gelatin and NaCN of various concentrations were chosen for rheological investigations at 20°C. Tensiometric and rheological investigations showed presence of interaction between gelatin A and Na caseinate, and also was evident that at certain proteins ratio complex coacervation occurs. Tensiometric measurements showed that changes of surface tension occur always at the same NaCN concentration, independent on gelatin concentration, as well as coacervate apperance.

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Interfacial properties of proteins: Hofmeister effects on surface charge of BSA Luca Medda ; Francesca Cugia ; Andrea Salis ; Maura Monduzzi University of Cagliari, Chemical and Geological Sciences, Monserrato (CA), Italy

Potentiometric titrations and electrophoretic measurements are two powerful techniques for the characterization of proteins. Both techniques allow to determine the surface charge of a protein as a function of pH. This is an important information because the knowledge of the electrical charge is the basis of the understanding of a series of phenomena such as protein precipitation and adsorption. In turn, these phenomena are of utmost importance both in medicine (neurodegenerative disorders like Alzaimer’s disease, Parkinson’s disease, as well as amyotrophic lateral sclerosis)1and biotechnology (i.e. enzyme immobilization).2 The surface charge was measured as a function of pH for BSA in the presence of different sodium salts (0.1 M) through potentiometric titrations and electrophoretic measurements, and the ion specific differences of BSA surface charge (|ΔZp|=|ZpX-ZpCl| were determined for the anions Bromide, Nitrate, Iodide, and Thiocyanate. Clear Hofmeister effects on potentiometric titrations and zeta potential measurements of BSA as a function of pH were observed. The trends of titration curves obtained with the two methods do not coincide since they provide different information. For potentiometric titrations the protein charge is only due to bound and unbound protons.3 Zeta potential measurements, instead, take into account all the ions present in the system which can affect the effective charge of the protein.4 Although so much time has gone from Hofmeister’s original experiments, ‘ion specific phenomena’ are still attracting the interest of the scientific community.5 Here, ion specific BSA titrations are investigated to shed some new light on the mechanism of Hofmeister effects in protein systems. References: 1. Kakizuka, A. Trends in Genetics 1998, 14, 396. 2. Salis, A. et al. J. Phys. Chem. B 2010, 114, 7996. 3. Salis, A.et al. Langmuir 2011, 27, 11597. 4. Salis, A. et al. Phys. Chem. Chem. Phys. 2012, 14,4343 5. Lo Nostro, P. et al. Chem. Rev. 2012, 112, 2286.

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Smart lipid assemblies for DNA complexation: structure at the nanoscale and interaction with membrane models Costanza Montis ; Piero Baglioni ; Debora Berti University of Florence and CSGI, Department of Chemistry, Firenze, Italy

The association of lipid assemblies with nucleic acids has been the subject of intense investigation, for the development of DNA vectors for therapeutic purposes. Fundamental research in this area has been directed to the elucidation the structural features in relation with the experimental conditions, the chemical nature of the lipids and of the nucleic acids. However, the design of efficient nanostructured vectors implies also the knowledge of their behavior in biologically relevant media and interaction with cell mimic systems. In this contribution we report on the properties of nucleolipoplexes, from DNA and the nucleolipid POP-Ade (1-Palmitoyl-2-oleoyl-sn-glycero-3-phosphatidyladenosine) with two zwitterionic helper lipids, POPC (1-Palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine) and DOPE (1,2-dioleoyl-sn-glycero-3-phosphoethanolamine). Depending on the helper lipid, these complexes show a different liquid crystalline internal phase and a different morphology on the mesoscale, as visualized through Laser Scanning Confocal Microscopy. The structural characterization was correlated with the dynamic properties of a fluorescent probe diffusing within the lipid phase of the complexes monitored with Fluorescence Correlation Spectroscopy. Interestingly, it was possible to distinguish the liquid crystalline phase from the dimensionality of diffusive motions. Finally, the interaction of POP-Ade nucleolipoplexes with cell membrane models (Giant Unilamellar Vesicles, GUV) was investigated. The fusion between nucleolipoplexes and GUVs bilayers was observed in real time through LSCM and was found to be dependent on two main factors: the helper lipid contained in the nucleolipoplexes and the charge density of the membrane model. Furthermore, FCS studies on the diffusion of the fluorescent probes inside GUV’s bilayer before and after the addition of nucleolipoplexes allowed to obtain dynamic information on lipid exchange and to elaborate hypothesis on the fusion process.

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Interaction between fullerene and vitamins Sabet Raessi ; Fereshteh Naderi Islamic Azad University, Shahr-e Qods, Islamic Republic of Iran

In this study, the ascorbic acid (vitamin C ,VITC) and pyridoxine (B6 ,VITB) radicals interacting with the C60 are reported using hybrid density functional theory (B3LYP/6-31+G(d)) calculations. The entire calculations were performed using Gaussian 98[1]. The structure of C60 obtained (Figure. 1a) is consistent with the literature [2-4], and the prediction of bond lengths (1.453Å for single bond and 1.395 Å for double bond) is in excellent agreement with the experimental values (1.458 and 1.401Å, respectively) [5-7]. The results demonstrate that the strong interactions between VITC- or VITB- radicals and the C60 lead to significant changes on the geometric properties. These calculations showed that the binding of vitamin C and vitamin B6 to C60 generated unstable complexes with destabilization energies of 6.43 and 6.54 eV respectively. Therefore, fullerene cages might be unable to form stable bindings to vitamins via their active sites. Resulting allows in interesting possibilities for the drug carrier under appropriate circumstances. These observations are extremely relevant in order to identify the potential applications of C60 as drug delivery

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Pressure dependence on penetration behavior of Vibrio cholerae Hemolysin into lipid monolayers on PBS subphase Yushi Oishi 1; Taka-aki Hirano 1; Hiroshige Seto 1; Hajime Ikigai 2; Takayuki Narita 1 1Saga University, Chemistry and Applied Chemistry, Saga, Japan; 2Suzuka National College of Technology, Chemistry and Biochemistry, Mie, Japan

Vibrio cholerae hemolysin (VCH) is a protein produced by V. cholerae, and it forms transmembrane channels in cell membranes containing cholesterol (Chol) and dimyristoylphosphatidylcholine (DMPC) to induce a strong cytotoxicity. It is, therefore, indispensible for clarifying the channel formation mechanism of VCH in membranes to examine by a single-component system (Chol and DMPC) under various conditions. In this study, the action and its surface pressure dependence of VCH to DMPC and Chol monolayers on PBS was investigated on the basis of an area-time isotherm measurement and an AFM observation. A chloroform solution of Chol or DMPC with a concentration of 1.0 x 10-3 M was spread on PBS at 293 K. Each monolayer was compressed to surface pressures of 3 and 20 mN/m. PBS or aqueous VCH was injected into the subphase with maintaining a given surface pressure and then, the variation of the monolayer area was measured. Area strain is obtained from γ = {-(A(t)-A(0))/A(0)} where A(0) is the monolayer area just after the compression and A (t) is the area after t s. After standing for 1h, the monolayer was transferred onto a freshly cleaved mica by the horizontal drawing-up method. Topographic images of the monolayer surface on mica were obtained by AFM in air. The area strains for Chol and DMPC monolayers at 3 mN/m monotonically decreased with time. This increase in monolayer area, that is, monolayer expansion indicates a penetration of VCH into monolayer or an aggregation of VCH in void in monolayer. On the other hand, the area strain of both monolayers at 20 mN/m increased consistently with time and almost remained constant after about 40000 s. Such a monolayer contraction may not arise only from the monolayer relaxation at a molecular or a morphological level but also the filling of vacancies in the monolayer with Chol or DMPC molecules under a constant surface pressure. It is, therefore, considered that a high surface pressure, in other words, an aggregation of lipid molecules prevents the penetration or aggregation of VCH in monolayer. The above-mentioned considerations was also accepted by the results of AFM observations.

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Interfacial effects in bio-molecules integrated into organic field effect transistors Gerardo Palazzo 1; Maria D. Angione 1; Maria Magliulo 1; Serafina Cotrone 1; Antonia Mallardi 2; Luisa Torsi 1 1University of Bari, Dept. of Chemistry, Bari, Italy; 2CNR-IPCF, Istituto per i Processi Chimico Fisici, Bari, Italy

Bio-systems interfaced to an electronic device is presently one of the most challenging research activity that has relevance not only for fundamental studies but also for the development of highly performing bio-sensors. In this presentation the full integration of bio-systems such as phospholipid bilayers or proteins into an organic field-effect transistor (OFET) structure is proposed. Strikingly, the results show that both the electronic properties and the bio-layer functionality are fully retained. The platform bench-tests involved phospholipids and bacteriorhodopsin integrating OFETs exposed to 1-5% anesthetic doses that reveal drug-induced membrane changes. This challenges the current anesthetic action model relying on the so far provided evidence that doses much higher than clinically relevant ones (2.4%) do not alter lipid bilayers structure, significantly. Furthermore, a streptavidin embedding OFET shows label-free biotin electronic detection at 10 part-per-trillion concentration level, reaching state-of-the-art fluorescent assay performances. Extensive explored control experiments show the detection is also highly specific. These examples show how the proposed bio-electronic platform, besides resulting in extremely performing biosensors, can open to gather insights into biological relevant phenomena involving interfacial modifications that can be electronically detected. References: [1] L. Torsi, G. Palazzo, D. Angione, N. Cioffi, M. Magliulo, S. Cotrone, G. Scamarcio, L. Sabbatini, A. Mallardi;. Field-effect transistors based on multilayers of self-assembled biological systems and organic semiconductor layer: processes for their realization and use as sensors;. European Patent. EP 10425146.7. [2] M.D. Angione, S. Cotrone, M. Magliulo, A. Mallardi, D. Altamura, C. Giannini, N. Cioffi, L. Sabbatini, E. Fratini, P. Baglioni, G. Scamarcio, G. Palazzo and L. Torsi; Interfacial electronic effects in functional bio-layers integrated into organic field-effect transistors. Proc. Natl. Acad. Sci. USA 2012, doi: 10.1073/pnas.1200549109

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Effects of calcium and bicarbonate on phase distribution of the reaction products and cholesterol as studied in in-vitro model Liliya Petrova 1; Zahari Vinarov 1; Slavka Tcholakova 1; Nikolai Denkov 1; Simeon Stoyanov 2; Alex Lips 3 1Sofia University, Faculty of Chemistry and Pharmacy, Department of Chemical Engineering, Sofia, Bulgaria; 2Unilever R&D, Vlaardingen, Netherlands; 3Unilever Discover, Port Sunlight Laboratory, Bebington, United Kingdom

In the human digestive tract, the pancreatic lipase is an enzyme which catalyzes the hydrolysis of water insoluble triglycerides into partially soluble fatty acids and 2-monoglycerides. In vivo these reaction products should be solubilized in the molecular aggregates of the bile salts (so called “bile micelles”) in order to be transferred to the walls of the small intestine and absorbed by the human body. In the current study we describe a relatively simple in vitro model for triglyceride (TG) lipolysis which mimics closely the conditions in the human stomach and small intestine. The main model advantages are: (1) As in vivo, sodium bicarbonate is used for buffering of the reaction mixture; (2) The pH-profile in small intestine is closely matched; (3) The experimental procedure does not include complex equipment. This model was applied to quantify the effects of Ca2+, pH, and bicarbonate buffer on the degree of TG lipolysis and on the solubilization of the lipolysis products and cholesterol in the aqueous phase. We found that TG lipolysis passes through shallow minimum at 3.5 mM Ca2+, while the increase of pH and the presence of bicarbonate lead to higher degree of lipolysis. Centrifugation and filtration were used to separate the aqueous phase and to study the solubilization of the various lipophilic components in the bile micelles. We found that the solubilized cholesterol increases linearly with the concentration of free fatty acids (FFA) which is an evidence for a co-solubilization of these two components in the bile micelles. At high Ca2+ concentration, aggregates larger than 300 nm were observed by cryo-microscopy and light scattering, which solubilize well cholesterol and saturated FFA. In contrast, monoglycerides were always predominantly solubilized in the small bile micelles with diameter around 4 nm.

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The role of surface ion binding in TiO2-platlet interactions.2 Swati Gupta ; Ilya Reviakine CIC biomaGUNE, Biosurfaces, San Sebastian, Spain

Interactions between surfaces of inorganic materials and biological systems are important in numerous technological contexts, such as implant integration and biosensor development. They also present basic challenges. Titania (TiO2) is an important biomaterial used in osteoimplants, stents, artificial heart valve housings. It has favourable biocompatibility properties, the molecular origins of which are only partially understood. We have been using model systems to investigate surface properties of TiO2 that are relevant to biomaterial performance. Surface ion equilibrium is one of those properties. Interactions between Ca2+ and TiO2 have been studied for some time. In this study, we investigated their relevance in the context of platelet activation on TiO2. Platelets are anuclear blood cells whose function is to maintain hemostasis. Like any other material, TiO2 activates platelets that come into contact with it. We find that platelet activation due to their interactions with TiO2 depends on whether Ca2+ is present or not. This effect is absent in the case of platelets interacting with glass or stimulated by agonists in solution and is therefore specific to the surface. We also show that platelet activation, which is a complex process involving the expression on the platelet surface and secretion into the surrounding media of a diverse array of adhesion molecules, pro-coagulant, pro-inflammatory, and angiogenic factors and cytokines, can be selective.

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Template-directed synthesis of mineral hollow capsules and investigations on dynamics of protein adsorption Marina Juliane Richter ; Alexander Schulz ; Alexander Boeker RWTH Aachen University, Aachen, Germany

The template-directed synthesis via mineralization of oil-water-emulsions is an easy way to obtain inorganic hybrid materials in the form of mineral hollow capsules. The matrix of the amphiphilic protein hydrophobin serves as a scaffold during the mineralization process on which ions can bind and induce crystallization. We are able to synthesize different mineral hollow capsules of hydroxyapatite in size up to 150 µm with different morphologies depending on the inserted oil. Investigations on dynamics of protein adsorption via pendant-drop measurements give important information about the behaviour of the protein at the interface that lead to an enhanced understanding of the present processes. The main focus is on the denaturation and reorientation processes of the protein that can be reached by adapting the measured time-dependent interfacial tension to protein models.

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Interaction of Glycyrrhizin with Lipid Rafts Model by Langmuir Monolayer Study Seiichi Sakamoto ; Hiromichi Nakahara ; Osamu Shibata Faculty of Pharmaceutical Sciences, Nagasaki International University, Departmnet of Biophysical Chemistry, Sasebo, Japan

Glycyrrhizin (GC) is the natural compound mainly produced from the root of licorice, which is contained in over 70% of prescrbed Japanese Kampo medicine. To date, uptake mechanism of GC has not been elucidated at the molecular level. In this study, the interaction of GC with lipid rafts model, which is the ternary mixture of N-palmitoyl-D-erythro-sphingosylphosphorylcholine (PSM), 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), and cholesterol (CHOL) was systematically studied by the Langmuir monolayer technique. The surface pressure (π) and surface potential (ΔV) were measured simultaneously using a homemade Wilhelmy balance and an ionizing 241Am electrode. The monolayer was directly visualized by a Brewster angle microscope (BAM) and a fluorescence microscope (FM) coupled to KSV Minitrough. In order to construct model for lipid rafts, Langmuir monolayer study of the binary monolayer (PSM/CHOL and PSM/DOPC) and ternary monolayer (PSM/DOPC/CHOL) has been primarily carried out. From BAM and FM images, the PSM/DOPC/CHOL (1/1/1) system is proven to be appropriate ratio as a model of lipid rafts. The interaction of GC with the ternary monolayer was then investigated, where GC (1, 5, 10, 25, and 50 µM) is dissolved in the subphase. BAM and FM images in three-component system revealed that GC regions with distinctive stripes of the liquid-expanded phase are also formed at 25 and 50 µM GC in the subphase. That is, the GC stripes divided the ternary monolayer into pieces. More interestingly, a lot of liquid-condensed domains are observed in the GC stripes. The domains are found to be made of CHOL, not PSM nor DOPC from the results for the one- and two-component systems. Therefore, it is suggested that GC improves the fluidity of lipid rafts by incorporating CHOL into GC regions. These results in the present study will allow us to show the possibility; GC helps uptake of bioactive compounds derived from Kampo medicines prescribed with licorice.

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Pectins from different plant sources and their effect on emulsion stability Ulrike S. Schmidt 1; Karin Schmidt 2; Karsten Koehler 1; Tomas Kurz 2; Hans-Ulrich Endress 2; Heike P. Schuchmann 1 1Karlsruhe Institute of Technology, Institute of Process Engineering in Life Sciences Section I: Food Process Engineering, Karlsruhe, Germany; 2Herbstreith&Fox KG Pektin-Fabriken, Neuenbuerg, Germany

Pectins are natural hydrocolloids that have already been used as gelling agents and stabilizers within the food industry for a long time. Their surface active properties, however, have mostly been neglected. Only sugar beet pectin has gathered some scientific interest due to its protein moiety that is held responsible for its good emulsifying capacity. For industrial application, however, pectins from apple pomace and citrus peel are more relevant. Here, gelling properties can be controlled by esterification and amidation. Currently, we are investigating in how far citrus and apple pectins are suitable for the stabilization of oil-in-water emulsions. In contrast to the common approach, we do not only characterize the “emulsifying capacity” but try to distinguish between molecule features responsible for oil droplet breakup and for subsequent stabilizing of the formed emulsion. Effects caused by an increase in viscosity are investigated separately from those caused by differences in surface tension, as both phenomena have an influence on droplet breakup as well as on stabilization. Through this approach, correlations between pectin structure and emulsion characteristics can be drawn. This, in turn, makes it possible to choose specific pectins according to particular emulsion requirements, as will be illustrated in detail.

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Reverse emulsions stabilized by water-dispersible microgels: anti-Bancroft Pickering emulsions Mathieu Destribats 1; Veronique Lapeyre 2; Elisabeth Sellier 3; Fernando Leal-Calderon 4; Veronique Schmitt 1; Valerie Ravaine 2 1University of Bordeaux, Centre de Recherche Paul Pascal CNRS, Pessac, France; 2University of Bordeaux, Institut des Sciences Moléculaires, Pessac, France; 3University of Bordeaux, Centre de Ressources en Microscopie Electronique et Microanalyse, Talence, France; 4University of Bordeaux, Laboratoire de Chimie et Biologie des Membranes et des Nano-objets, Pessac, France

Emulsions were prepared using poly(N-isopropylacrylamide) microgels as thermo-responsive stabilizers. These latter are well known for their sensitivity to temperature: they are swollen by water below the so-called volume phase transition temperature (VPTT=33°C) and shrink when heated above it. These microgels are known to stabilize oil-in-water (O/W) emulsions that undergo fast destabilization upon warming above the VPTT. In the present study, whereas O/W emulsions were obtained with a wide panel of oils of variable polarity and were all thermo-responsive, water-in-oil (W/O) emulsions were found only in the presence of fatty alcohols and did not exhibit any thermal sensitivity [1]. To understand this peculiar behavior, we investigated the organization of microgels at the oil-water interface. We provided evidence that W/O emulsions are stabilized by multilayers of non-deformed microgels located inside the aqueous drops. Such behavior is in contradiction with the empirical rule stating that the emulsion continuous phase is the one in which the stabilizer is preferentially dispersed. The study of microgels in non-emulsified binary water/octanol systems revealed that octanol diffused through the aqueous phase and was incorporated in the microgels. Thus, W/O emulsions were stabilized by microgels whose properties were substantially different from the native ones. In particular, after octanol uptake, they were no longer thermo-responsive, which explained the loss of responsiveness of the corresponding W/O emulsions. Finally, we showed that the incorporation of octanol modified the interfacial properties of the microgels: the higher the octanol uptake before emulsification, the lower the amount of particles in direct contact to the interface. The multilayer arrangement was thus necessary to ensure efficient stabilization against coalescence as it increased interface cohesiveness. [1] M. Destribats, V. Lapeyre, E. Sellier, F. Leal-Calderon, V. Schmitt and V. Ravaine “Water-in-oil emulsions stabilized by water-dispersible poly-N-isopropylacrylamide microgels: understanding anti-Finkle behavior” Langmuir (2011), 27, 14096

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Structure and Dynamics of Candida Antactica B in Microemulsions Mireia Subinya Albrich ; Julia Kupka ; Anne Steudle ; Sandra Engelskirchen University of Stuttgart, Institute for Physical Chemistry, Stuttgart, Germany

Nature provides a broad spectrum of efficient and specialized catalysts. We aim at applying these catalysts for the conversion not only of their natural substrates, but more importantly to convert non-natural substrates allowing us to synthesize products with high region-, stereo- and enantiomeric selectivity. Remembering thalidomide these key properties are more than essential in pharmaceutical applications. A challenge still faced is the often high lipophilicity of synthetically interesting substrates causing enzyme-substrate incompatibilities. Bicontinuous microemulsions can be applied to overcome these incompatibilities providing a high connected interfacial area between interpenetrating nanometer sized water and oil channels. In the present contribution we focus on dynamic and structural aspects of an enzyme being adsorbed to this connected interfacial layer. We intend to understand and clarify how the microenvironment that we provide induces changes in the enzyme conformation referring to the active centre and to reveal diffusion and adsorption of the enzyme at the interfacial monolayer. For this purpose we have chosen the lipase Candida Antarctica B the structure of which is well resolved in combination with a well-defined bicontinuous microemulsion consisting of H2O/NaCl – n-octane – surfactant. Using pfg-NMR and fluorescence techniques we present a first picture on dynamic properties of the studied enzyme in bicontinuous microemulsions. The secondary structure of the enzyme was studied by circular dichroism (CD) focussing on effects induced by the nature of the surfactant applied, which were related to a first series of activity studies performed.

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Characterization of human dental enamel by imaging spectroscopic ellipsometry Peter H. Thiesen 1; Christian Röling 1; Matthias Neuber 2; Andreas Kiesow 2 1Accurion GmbH, Göttingen, Germany; 2Fraunhofer Institute for Mechanics of Materials IWM, Halle (Saale), Germany

Imaging Ellipsometry is combining nulling ellipsometry with microscopy to measure the ellipsometric parameter Delta and Psi with a lateral resolution down to 1 µm. Nulling parts of the surface enable high contrast images of thin layers. Dental enamel is one of the major tissues that make up the tooth in vertebrates. To answer a number of questions, like aesthetics aspects of dental restorations, efficiency of tooth cleaning or the quantification of discoloration by adsorption of chromogens from tobacco, coffee, or tea, the optical characterization of human dental enamel is of high scientific and technical relevance. Experimental Materials: Human molars and incisors were cut; cross sections were embedded in polymer resin, ground and polished. Method: Ellipsometric contrast micrographs and Psi-maps were recorded at 402 nm in one zone. Wavelength spectra were recorded in between 360 and 1000 nm. For same samples, smaller wavelength ranges (400 to 800 nm) or separate wavelengths were selected. The wavelength spectra were always recorded in four zones and by using an internal and external beamcutter, respectively. The optical modeling was performed with the software program nanofilm_ep4model. Results: The optical modeling of the ellipsometric parameter will be discussed due to the selection of the dispersion function, roughness and water adsorption. Ellipsometric contrast micrographs, Delta- and Psi maps of human incisor (cross secion) will be reported. As an example, the run in refractive index (631 nm) representing five images each including five regions of interest (ROI) will be presented displayed. The refractive index exhibit values of about 1.62 for the enamel, decreasing values going to the enamel-dentin-transition, and a clear step between the values of ROIs, focused on enamel-dentine. Outlook: In situ experiments and imaging NIR-ellipsometric investigations with the focus on detecting structure changes in the surface are in preparation. Further investigations aim on analyzing the optical anisotropy of the dental tissue in correlation with structure properties and the influence of the water content on the optical behavior.

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Challenges around colloid and interface science when formulating agrochemical active ingredients Pauline Vandoolaeghe Syngenta Crop Protection Münchwilen AG, Münchwilen, Switzerland

The agrochemical industry is facing challenges daily around colloidal and interfacial science. Agrochemical products are usually quite complex colloidal systems, commonly consisting of disperse systems such as suspensions of solid particles in a liquid, emulsions and mixtures of these (suspoemulsions). Other types of formulations, e.g. micro-emulsions, capsules, polymer dispersions, controlled-release granules, or multiple emulsions are now more and more developed to get some more specific effects, such as controlled release of the active ingredient or to make the product safer to handle. One challenge is thus to prepare physically and chemically stable formulations upon storage, but also stable products upon high dilution. The grower will thus dilute the product in the tank of his spraying equipment and need to be able to apply the product without experiencing, e.g. nozzle blockage or too strong foam formation. Another challenge is to obtain the desired biological effect. In this matter, agrochemical challenges are quite similar to the ones faced by the pharmaceutical industry. A good understanding of the interfacial interactions between the formulation components and the solid surfaces (leaf surface, soil, roots), as well as of the drying phenomena, is critical to be able to tune or improve the biological performance. The product needs first to adhere to the surface, and in many cases to penetrate into the leaf or the root to show some efficacy. Being able to deliver at the active site is also crucial in order to develop sustainable products, i.e. reducing the environmental impact by decreasing the amount of active ingredient used to obtain the same performance. Some typical examples of challenges which the agrochemical industry are facing, as well as approaches to meet them, will be presented, including controlled/triggered release, targeted delivery, and penetration enhancement.

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Bioinspired synthesis of silica capsules Huihui Wang 1; Andreea Balaceanu 2; Guenes Kibar 1; Andrij Pich 2; Ulrich Schwaneberg 1; Alexander Boeker 1 1RWTH Aachen University, Aachen, Germany; 2DWI an der RWTH Aachen e.V., Aachen, Germany

The typical chemical process for silica synthesis relies on extreme reaction conditions of pH value, temperature and pressure. However, natural organisms such as diatoms or sponges can produce silica at mild conditions. Silicatein, an enzyme isolated from silica spicules of marine sponge has been found to be enzymatically active for biosilicification. The catalytic synthesis of silica capsules is performed in an emulsion system, consisting of a silica precursor as oil phase and an aqueous solution of recombinant silicatein. Silicatein is able to initiate and stabilize the emulsion like a surfactant, serving as template for capsule formation and at the same time enzymatically catalysing the in vitro polycondensation of the silica precursor at the interface to form silica capsules. By changing parameters like the ratio of silica precursor to silicatein solution, the precursor as well as the emulsification method, we can control the size and morphology of the capsules. Besides silicatein, also polymers with a large number of amine groups as well as small amine molecules are reported to catalyse the silicification. Therefore, PNIPAAm microgels with high interfacial activity were also successfully employed for the catalytic synthesis of silica capsules. The use of artificial particles supporting the silicification presents a convenient alternative to the biological catalysis as PNIPAAm is accessible in large amounts and the respective particles can easily be modified to introduce different functionalities on the surface of the silica capsules.

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In-vitro study of the effect of surfactants on triglyceride lipolysis under conditions mimicking the human digestive tract Zahari Vinarov 1; Borislava Damyanova 1; Yana Petkova 1; Yasen Atanasov 1; Slavka Tcholakova 1; Nikolai Denkov 1; Simeon Stoyanov 2; Alex Lips 3 1Sofia University, Faculty of Chemistry and Pharmacy, Department of Chemical Engineering, Sofia, Bulgaria; 2Unilever Research Centre, Vlaardingen, Netherlands; 3Unilever Research Centre, Colworth, United Kingdom

During digestion, the pancreatic lipase (an enzyme) catalyzes the hydrolysis of water insoluble triglycerides (TG) into partially soluble fatty acids and monoglycerides. The latter are then solubilized by bile salts (biosurfactants) and absorbed in the human body. As the action of this lipase is accomplished after adsorption on the water-TG interface, the presence of surfactants could significantly affect its activity. Here we study the effects of surfactant type (anionic, cationic and nonionic) and concentration on the lipolysis of sunflower oil emulsions, in presence and in absence of bile salts (BS). In absence of BS, for all systems, we observe 3 regions for the TG lipolysis, L, when the surfactant concentration (Cs) is scaled with CMC: (1) At Cs < CMC, L = 0.5. (2) At Cs = 3xCMC, L = 0.15. (3) At Cs >> CMC, L = 0 for all studied surfactants. Additional experiments show that the lipase hydrolyzes molecularly soluble substrate at Cs >> CMC, proving that these surfactants do not block the enzyme active center. Thus we conclude that the mechanism of enzyme inhibition by these surfactants is the formation of dense adsorption layer on oil drop surface, which displaces the lipase from direct contact with the TG. In presence of BS, for all systems, we observe 3 regions in the dependence of L versus the surfactant-to-BS ratio, fs: L = 0.5 in Region 1 (fs < 0.02); a maximum of L = 1 is passed in Region 2 (0.02 < fs < fTR); L = 0 in Region 3 (fs > fTR). The threshold ratio for complete inhibition of lipolysis, fTR, depends on the surfactant type. Measurements of interfacial tensions and optical observations revealed that: In Region 1, the surfactant is solubilized in BS micelles and the interface is dominated by BS molecules. In Region 2, mixed surfactant-BS micelles are formed, which rapidly solubilise the lipolysis products, leading to complete lipolysis. In Region 3, the surfactant prevails in the adsorption layer and completely blocks the lipolysis.

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Reverse micellar nanosystems for enzymic biocatalysis: structure-activity relationship Karen Gonçalves 1; Vassiliki Papadimitriou 2; Maria Zoumpanioti 2; Ivana Leal 1; Rodrigo O.M.A. de Souza 3; Y Cordeiro 1; Aristotelis Xenakis 2 1Federal University of Rio de Janeiro, Faculdade de Farmácia, Rio de Janeiro, Brazil; 2National Hellenic Research Foundation, Institute of Biology, Pharmaceutical Chemistry & Biotechnology, Athens, Greece; 3Federal University of Rio de Janeiro, Dep. de Química Orgânica, Rio de Janeiro, Brazil

Lipases are triacyl glycerol acyl hydrolases which apart hydrolysis of esters, can also catalyze esterification and transesterification reactions. These enzymes act at an interface between aqueous and non-polar phases and have widespread applications in biotechnology and in biomedical sciences. In the present work, we investigate conformational changes of Thermomyces lanuginosus lipase (TLL) and Lecitase ultra phospholipase in AOT/isooctane reverse micelles. These nanosystems provide a high interfacial area of contact and can promote interfacial activation, important to their catalytic activity. Inside micellar environments, the fluorescence spectra of the incorporated enzymes were blue-shifted relative to the spectra of free enzyme in aqueous environment, indicating that incorporation into micelles led to changes in the enzyme tertiary structure. Small-angle X-ray scattering (SAXS) analysis showed that the radius of gyration changed from 16 to 38Å, when the water content was increased (wo = [H2O]/[AOT]). When the enzymes are inserted into these systems, a small decrease in radius, compared to the empty micelles, was observed at wo values higher than 10 and electronic paramagnetic resonance (EPR) experiments showed a small increase in spin probe’s (5-doxyl stearic acid) mobility, which indicates the presence of these lipases at the AOT interfacial layer; however, this effect is not so profound on the membrane rigidity. The activity was measured by the esterification between oleic acid and ethanol (1:2) and the best obtained systems with TLL and Lecitase ultra were those with wo of 8 and 10, with conversions after 1h at 20 and 29%, respectively. Despite the observed conformational changes, the enzymes did not lose activity upon incorporation into the micelles.

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Interactions of PAMAM dendrimers with designer biosurfactants Marianna Yanez Arteta 1; Caroline Eriksson 1; Debora Berti 2; Piero Baglioni 2; Tommy Nylander 1 1Lund University, Physical Chemistry, Lund, Sweden; 2University of Florence, Department of Chemistry and CSGI, Florence, Italy

The synthesis of poly(amidoamine) (PAMAM) dendrimers was reported almost two decades ago by Tomalia and collaborators and their well-defined hyperbranched molecular architecture and their cationic charge make them potential vehicles for gene therapy. Recently, novel nucleic acid base surfactants/lipids, have generated interest due to their capacity for molecular recognition of DNA and RNA, which ordinary PAMAM dendrimers do not have. One example is the dilauroylphospholiponucleosides (DLPN) derivatives, which associate in solution as semi-flexible wormlike aggregates.Combination of PAMAM dendrimer with nucleic acid surfactant will open up the possibility to tune the structure of the formed complex as well as to provide means for molecular recognition and directed self-assembly. We have therefore studied the interactions of PAMAM dendrimers generation 4 with DLPNs based on adenosine (DLPA) and uridine (DLPU) in bulk and at the solid/liquid interface using a combination of electrophoretic mobility (EM) measurements, dynamic light scattering, small angle x-ray scattering, cryo-TEM and quartz crystal microbalance with dissipation monitoring (QCM-D). At pH 7, the cationic dendrimer interacts strongly with the oppositely charged DLPN, forming aggregates of different charge depending on the PAMAM/DLPN ratio as confirmed by EM measurements. Cryo-TEM has shown the formation of PAMAM/DLPA aggregates with different morphologies, as irregular toroids. Similar structures have previously been observed for complexes between DNA with PAMAM. QCM-D data showed the formation of a rigid layer, apparently independent of the surfactant concentration, as DLPA interacts with a preadsorbed PAMAM dendrimer monolayer on a silica substrate. The adsorption appears to be partially irreversible but a softer layer is obtained if the system is rinsed after the addition of DLPA. Results from studies of the interactions of PAMAM/DLPNs mixtures with ssDNA will also be presented.

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New sunscreen emulsions containing polyphenolic extracts; stability and in vitro photoprotective activity and photostability efficacy Jarzycka Anna ; Kazimiera A. Wilk ; Roman Gancarz Wroclaw University of Technology, Organic and Pharmaceutical Technology Group, Faculty of Chemistry, Wroclaw, Poland

The work reported here extends our recent studies on new carriers of bioactive substances, their fabrication, colloidal and physicochemical stability and biological response. To meet consumers’ expectations, a modern cosmetic product must fulfill numerous demands, and as the most important, efficacy, high quality and safety have to be achieved. The aim of the present contribution was to investigate the photoprotective activity and photostability efficacy of the sunscreen formulations containing Helichrysum arenarium, Sambucus nigra, Crataegus monogyna extracts and their combination. Photostability is the essential parameter characterizing both the effectiveness and safety of sunscreen products, since the ultraviolet radiation can lead to reduction of cosmetics photoprotective ability and can generate free radicals. UV transmission of the emulsions films was performed by using diffuse transmittance measurements coupling to an integrating sphere. In vitro photoprotection and photostability efficacy were evaluated according to the following parameters: sun protection factor (SPF), UVA protection factor (PF-UVA), UVA/UVB ratio and critical wavelength (λc) before and after UV irradiation. The obtained results show that the formulations containing polyphenols fulfill the official requirements on sunscreen products due to their broad spectrum of UV protection combined with their high photostability and remarkable antioxidant properties. The combination of these two features moves up the studied cosmetic emulsions and extracts to the class of cosmeceuticals, and makes them potential active ingredients of sunscreen commercial formulations mostly due to their cosmetics, protective and preventive properties.

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Synthesis and polymerization kinetics of sterically stabilized perfluorinated aqueous latex Dominik Burger ; Rene Schneider ; Eckhard Bartsch University of Freiburg, Department of Macromolecular Chemistry, Freiburg, Germany

With the aim of studying the structure and dynamics of aqueous dispersions of hard sphere-like colloidal particles at high concentrations as well as their interactions with free polymer via light scattering we set out to synthesize new model colloids which are sterically stabilized, but at the same time nearly isorefractive to aqueous media. For this purpose we chose the perfluorinated monomer 2,2,3,3,4,4,4-Heptafluorobutyl methacrylate which was copolymerized with the macromonomer Poly(ethlene glycol) (PEG) methylether-methacrylate in a standard emulsion polymerization process. All batches gave monodisperse particles which showed colloidal stability. To establish these sterically stabilized perfluorinated particles as a model system, it is necessary to understand the process of particle formation as well as the manner of attachment of the stabilisation polymer onto the particle surface. Thus, we monitored the kinetics of polymerisation by using NMR spectroscopy and dynamic light scattering. In the very early stage of the reaction the conversion of monomer is low while the amount of macromonomer decreases linearly in time. This linear decrease continues throughout the particle growth stage and turns into an exponential dependence when particle growth ends. This kinetics can be rationalized by assuming that the macromonomer acts as a surfmer. In addition we could demonstrate that combining seeded growth emulsion polymerization and atom transfer radical polymerisation is a promising alternative route to generate perfluorinated latex with a PEG stabilization layer. The results indicates that this approach allows to control the core and the shell size independently, thus allowing for small shells of the stabilization polymer.

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Generic, thermo-reversible assembly of colloids in microtubes Julius de Folter 1; Lingxiang Jiang 1; Jianbin Huang 2; Albert Philipse 1; Willem Kegel 1 1Utrecht University, Physical and Colloid Chemistry, Utrecht, Netherlands; 2Peking University, National Laboratory for Molecular Sciences, Beijing, China

We introduce microtubular cyclodextrin-surfactant complexes as host for the thermo-reversible self-assembly of colloids into a library of 1D structures. The microtubes are formed in the presence of colloidal particles upon cooling the mixture to room temperature, and in this process, the particles self-assemble in the microtubes into chainlike structures with lengths varying from a few up to tens of microns. We show that the co-assembly of cyclodextrin-surfactant complexes and colloids is generic for colloids with different shapes (spheres, cubes), materials (silica, iron oxide, polystyrene) and sizes. The ratio between the particle and tube diameter is a key parameter governing the assembly behavior: (1) ordered, highly mobile structures are formed for particles smaller than the tube diameter, (2) ordered, immobile structures are obtained for particle sizes close to the tube diameter and (3) disordered, out-of-tube structures are observed for particles larger than the tube diameter. Depending on this ratio, the family of 1D structures ranges from single chains to zigzags, zippers, and double helices. Furthermore, the colloidal structures are present throughout the sample volume. We show that ordered structures become isotropic at elevated temperatures, but restore upon cooling. Other advantages are that the colloid-in-tube assembly can be observed in-situ and can easily be scaled up to tens of grams. We believe that our novel assembly approach provides significant contributions to the alignment, transportation, and controlled release of particles.

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Nanoemulsification process inspired by extreme environment in deep-sea Shigeru Deguchi ; Nao Ifuku Japan Agency for Marine-Earth Science and Technology, Institute of Biogeosciences, Yokosuka, Japan

Oil and water do not mix, but they do mix freely at high temperatures and pressures near the gas/liquid critical point of water (Tc = 374°C, Pc = 22.1 MPa). We used this phase behavior to develop a novel bottom-up emulsification process. Water and dodecane (1 vol%) were mixed at temperatures up to 408°C and at a constant pressure of 25 MPa using a flow-type instrument. The mixtures were then quenched at a rate of approximately 70-100°C/sec by mixing them with cold water containing 10 mM of polyoxethylene (10) oleyl ether (Brij 97). Emulsions thus obtained were depressurized and collected. Droplet size in emulsions was studied by dynamic light scattering. The process was fast, and took less than 10 seconds from mixing to sample collection. Thermal degradation of dodecane was suppressed to less than 1 % due to brief exposure time (~4.5 sec) to high temperature. O/W nanoemulsions containing dodecane droplets smaller than 100 nm were obtained when water and dodecane were mixed at temperatures above 373°C. At the highest mixing temperature, O/W nanoemulsion containing monodisperse dodecane droplets whose average diameter was 61 nm was obtained. In contrast, unstable emulsions containing significantly larger droplets resulted when water and dodecane were mixed below 373°C, suggesting that it was critical to mix water and dodecane in a one-phase regime to obtain stable nanoemulsions by this process. Effect of oil content and oil type will also be discussed.

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Functional silica coated superparamagnetic iron oxide nanoparticles (SPIONs) – preparative aspects and characterization Reinaldo Digigow 1; Hervé Dietsch 2; Barbara Rothen-Rutishauser 1; Alke Petri--Fink 1 1Adolphe Merkle Institute, University of Fribourg, Bionanomaterials group, Marly, Switzerland; 2BASF SE, Ludwigshafen, Germany

The purpose of this study was to prepare and characterize functional silica hybrid magnetic nanoparticles (SHMNPs). Chemical hydrolysis followed by condensation of the 3-aminopropyltriethoxysilane and tetraethyl orthosilicate (APTES/TEOS) mixture in the presence of superparamagnetic iron oxide nanoparticles (SPIONs) led to the production of magnetic silica nanoparticles containing primary amino groups on their surface. Many different samples were synthesized and the study focused upon the preparative aspect and characterization of the silica coated SPIONs in terms of their size, morphology, surface properties, and magnetic responses as determined using electron microscopy (TEM), dynamic light scattering (DLS), inductively coupled plasma optical emission spectrometry (ICP-AES), UV-Visible spectrophotometry (UV-VIS) and vibrating sample magnetometry (VSM). It was observed that depending on the mass ratio of the starting materials (either magnetic (SPIONs) or non-magnetic (TEOS and APTES)) the magnetic properties and surface charge of the obtained NPs could be regulated between different sample batches. Due to the magnetic properties and the presence of the primary amino groups on their surface, these magnetic silica nanoparticles can be manipulated for grafting polymers, target peptides, dyes and others biomolecules in order to obtain stable and high quality functionalized NPs for biomedical and biochemical applications in therapeutics and diagnostics.

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Production of monodisperse Pickering emulsions David French ; Andrew Schofield ; Paul Clegg University of Edinburgh, School of Physics & Astronomy, Edinburgh, United Kingdom

We have created monodisperse dodecane-in-water emulsions stabilised solely by colloidal silica particles. This was done by injecting the dispersed phase into a coflowing continuous phase (in a rotating container) which contains the particles. Polydispersity is minimised by keeping the flow rates of the two phases low and constant. By investigating the effects of injection rate, rotation rate and particle volume fraction on droplet stability we hope to quantify particle adsorption timescales and efficiencies. The monodisperse emulsions will also be used to study the effects of shear rate on droplet size.

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Semi-interpenetrating p(HEMA)/PVP hydrogels for the cleaning of water-sensitive canvas paintings Rodorico Giorgi ; Joana A.L. Domingues ; Nicole Bonelli ; Florence Gorel ; Piero Baglioni University of Florence, Csgi-Department of Chemistry, Sesto Fiorentino, Italy

Cleaning of cultural heritage artifacts enables to fight the natural effect of time by restoring the original appearance of the artwork. Nowadays, aqueous cleaning is usually preferred to organic solvents mainly because it is environmental friendly. Unfortunately, easel paintings present specific characteristics that make the usage of water-based systems invasive. The interaction of water with wood support or linen canvas favor mechanical stresses between the substrate and the paint layers, so that often detaching of the pictorial layer are observed. The usage of water-based detergent systems offer several advantages in terms of selectivity and gentle removal, layer by layer, of soil materials or aged varnish, which are known to alter the readability of the painting. In order to benefit of this advantages it is necessary to confine the detergent system in a gel with very high retention capability to minimize the effect of water. In this contribution, the confinement and release control of the water-based detergent system is achieved through the synthesis and application of innovative chemical hydrogels specifically designed for cleaning water-sensitive cultural heritage artifacts. These are based on semi-interpenetrating p(HEMA)/PVP networks with suitable mechanical strength and rigidity to avoid gel residues after cleaning treatment. Two different compositions were selected. Water retention and release properties have been assessed. The amount of free and freeze-bound water was quantified by Differential Scanning Calorimetry (DSC) measurements, while mesoporosity was investigated by Scanning Electron Microscopy (SEM). To demonstrate both the efficiency and versatility of the selected hydrogels in confining the most appropriate cleaning system (pure water and oil-in-water microemulsion) two representative case studies are presented.

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Preparation of HIPEs with controlled droplet size containing lutein Gemma Gutierrez ; Maria Matos ; Jose Coca ; Carmen Pazos University of Oviedo, Department of Chemical and Environmental Engineerig, Oviedo, Spain

Lutein is a natural carotenoid, found as lipid soluble pigment in several vegetables and egg yolk. Although lutein and its isomer zeaxanthin are found naturally in human skin, they behave as antioxidants, that could play an important role via ingestion or topical application. Emulsions with high internal phase concentration (HIPEs) are widely used in pharmaceutical, food and cosmetic industries. However, formulation of these oil-in-water (O/W) emulsions with a controlled droplet size is not an easy task. In this work, a two-step technique to prepare concentrated O/W emulsions containing lutein is proposed . First, a dilute O/W emulsion is prepared by membrane emulsification, followed by a vacuum evaporation to obtain the HIPEs. Deionised water containing 2 wt% of Tween 20 as emulsifier and various concentrations of sodium carboximethylcellulose (CMCNa) were used as continuous phase. Four types of oils were employed as internal phase: castor, heavy mineral, light mineral and soybean oil. A hydrophilic metallic membrane of 5 µm pore size was used to prepare the emulsions. The internal phase maximum concentration reached by subsequent evaporation was determined when the monodispersity of the emulsion decreased and changes in the mean droplet size were observed. The best monodispersity and maximum internal phase concentration was reached when soybean oil was used as internal phase and 0.5 wt% of CMCNa was added to the continuous phase. This formulation was selected for subsequent experiments performed with lutein. Satisfactory results were obtained in the preparation of HIPEs with controlled droplet size containing lutein with a concentration of internal phase up to 86 wt %. Droplet size distributions were measured during the evaporation process and micrographs of the emulsions were also analyzed using an Olympus BX61. Lutein concentration in the continuous phase was measured using a Spectrometer VIS/UV at 660 nm.

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Surface decoration of catanionic vesicles by magnetic iron oxide nanoparticles for on-demand delivery in mild hyperthermia

Gaelle Bealle 1; Lenaic Lartigue 2; Claire Wilhelm 2; Johann Ravaux 3; Florence Gazeau 2; Renaud Podor 3; Christine Menager 1; David Carriere 4 1Université Pierre et Marie Curie, PECSA, Paris, France; 2Université Paris Diderot, MSC, Paris, France; 3CEA Marcoule, ICSM, Bagnols sur Ceze, France; 4CEA Saclay, LIONS, Gif sur Yvette, France

Magnetic drug carriers made from polymersomes, multilamellar vesicles or liposomes are widely used for targeting, imaging and localized drug delivery applications in cancer therapy. Most of current studies focus on the presence of magnetic nanoparticles in the aqueous core of vesicles for delivery of encapsulated active compounds by means of hyperthermia, i.e. enhancement of the vector permeability upon stimulation of superparamagnetic nanoparticles by an external oscillating magnetic field. But this heating is sometimes significant and may denaturate or destroy therapeutic molecules. Instead of the usual encapsulation in the aqueous core, we suggest a distribution of superparamagnetic γ-Fe2O3 magnetic nanoparticles over the surface of the vesicles. For this purpose, we tuned catanionic vesicles preparation to absorb magnetic nanoparticles onto their surface. We will present their magnetic properties, in particular their ability to be guided in a static gradient field, and we demonstrate that hydrophilic molecule delivery can be externally triggered by an AC magnetic field without hyperthermia : thermal destruction of the cargo is avoided during magnetic stimulation thanks to heat generation in the vicinity of the bilayer only.

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Completely water dilutable green microemulsions Julien Marcus ; Michael Klossek ; Didier Touraud ; Werner Kunz Institute of Physical and Theoretical Chemistry University of Regensburg, Regensburg, Germany

The realms-of-existence of an optimized anti-percolative water/sodium oleate/citronellol/ limonene green microemulsion system using a 1:1 weigth ratio sodium oleate (surfactant) to citronellol (co-surfactant) is reported and characterized using a partial pseudo-ternary phase representation and electrical conductivity measurements. Keeping the same surfactant/co-surfactant ratio and a surfactant + co-surfactant/limonene ratio equal to 0.6, the gradual substitution of citronellol by ethanol allows an increase of water solubilisation depending on the ethanol/citronellol mixing ratio, and an extent of the microemulsion area. In the presence of a low ethanol content microemulsions remain of water-in-oil (W/O) type. For at least 30% of ethanol in the co-surfactant blend a percolative behavior is observed at low water content. This behaviour can be modified and shifted towards an anti-percolative behaviour adding water for co-surfactant blends 30 and 40% of ethanol. Between 30 and 90% of ethanol in the co-surfactant blend, lamellar and cubic phases appear adding large quantites of water. Above 90% of ethanol in the co-surfactant blend bicontinuous and fully aqueous dilutable oil-in-water microemulsions appear in presence of important quantity of water. Near of the phase transition of this fully dilutable microemulsion, rapid addition of water can drive to the formation of thermodynamically unstable translucid nanoemulsions, which turn into transparent microemulsions with time. This fact and the evolution of a percolative to an anti-percolative system adding water can be associated to a transitory favourable kinetic and finally stable thermodynamic solubilisation of ethanol in water in the continuous phase or in the water pool of the W/O microemulsions respectively. Globally, at low concentration ethanol contributes always to the interfacial film of sodium oleate and citronellol. Increasing the concentration of ethanol (over 90%), this short alcohol can contribute to the polymer-like film of the bicontinuous microemulsion and allows the formation of O/W fully dilutable microemulsion.

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Formulation of homogeneous, nano-structured mosquito repellent solutions with p-menthane-3,8-diol (PMD) as active in presence of ethanol and sesame oil Laura Egel ; Michael Klossek ; Didier Touraud ; Werner Kunz Institute of Physical and Theoretical Chemistry University of Regensburg, Regensburg, Germany

P-menthane-3,8-diol (PMD) is a well-known natural active in mosquito repellents. Its use in the presence of vegetable oils is limited by a strong tendency to crystallize. As this negative behaviour can be avoided in the presence of ethanol, the formulation of ternary solutions ethanol/ PMD/ sesame oil was decided. The model system ethanol/ 1-hexanol/ rapeseed oil was first investigated. It appeared that 1-hexanol allowed the co-solubilisation of ethanol and rapeseed oil. Dynamic light scattering (DLS) measurements of different formulations showed correlation functions which indicate the presence of nano-clusters. Using this model system, the formulation of ternary solution with 35% (w/w) of PMD was decided, with contents of sesame oil between 0% and 65% (w/w). Like 1-hexanol, PMD allowed the co-solubilisation of ethanol and the vegetable oil. Ethanol prevented strongly the crystallisation of PMD. New DLS measurements showed still some correlation functions indicating nano-structures for formulations having between 30% and 60% (w/w) of sesame oil.

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DNA mediated complex formation of cationically modified triglyceride nanocrystals for gene delivery Charlotte Knittel ; Martin Schmiele ; Tobias Unruh Friedrich-Alexander University Erlangen-Nuremberg, Crystallography and Structure Physics, Erlangen, Germany

Cationically surface-modified triglyceride nanocrystals were studied as a new promising type of DNA carrier system for gene therapy. Using a blend of non-ionic stabilizers like phospholipids, polysorbates or poloxamers together with the cationic surfactant dimethyldioctadecylammonium bromide (DDAB), stable aqueous dispersions of triglyceride nanocrystals were obtained by high-pressure melt homogenization. The nanocrystals possess a plateletlike shape with typical diameters of 150 nm and an aspect ratio of about 10. Addition of DNA to the dispersions leads to the formation of particle stacks with the platelets lying on top of each other, as it was verified by Small-Angle X-ray and Neutron Scattering techniques using the "X-ray Powder Pattern Simulation Analysis" [1] and by Electron Microscopy. Thereby, due to their anionic character, the DNA is supposed to adhere on the large flat 001-faces of the cationically modified triglyceride nanocrystals, acting as bonding agent between the individual platelets. By this approach, the intercalated DNA is presumably well protected against chemical degradation. Furthermore the stacks turned out to be very stable under dilution. However, at higher nanocrystal concentrations (>1% wt) and/or using high amounts of DDAB and DNA the preparation technique suffers from a chaotic aggregation of the platelets with the DNA, resulting in complexes in the micron size range what is unacceptable for potential pharmaceutical applications. To produce complexes with well-defined sizes, it is therefore essential to optimize the formulation of the cationic nanoparticle dispersions and especially to find a way to control the aggregation behaviour when adding DNA. [1] T. Unruh. Interpretation of SAXS patterns of crystalline triglyceride nanoparticles in dispersion. J. Appl. Cryst., 40, 1008-1018 (2007)

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Preparation of water-in-oil-in-water (W1/O/W2) double emulsions containing Resveratrol Maria Matos ; Gemma Gutierrez ; Jose Coca ; Carmen Pazos University of Oviedo, Department of Chemical and Environmental Engineerig, Oviedo, Spain

Double emulsions have potential applications in the food, cosmetic and pharmaceutical industries as vehicles for encapsulation and delivery of nutrients during food digestion or for drug release. In this work, (W1/O/W2) emulsions have been prepared to encapsulate resveratrol, a natural polyphenol with antioxidant activity. The water-in-oil (W1/O) emulsions were prepared by mechanical agitation and their stabilities were measured by analyzing the droplet size distributions with a laser diffraction particle size analyzer and the backscattering profiles obtained with a Turbiscan apparatus. The inner emulsion was prepared by mechanical agitation and the external emulsion by mechanical agitation and direct membrane emulsification using a metallic membrane of 5 µm pore size. The droplet size distributions of the double emulsions prepared by both techniques were measured and compared. The emulsions microstructure was also determined with confocal microscopy. The encapsulation efficiency of these emulsions and their stability as a function of time was measured. Ethanol 20 wt % and 0.1M NaCl solutions containing resveratrol were used as internal water phase. The oily phase was Miglyol 812 or soybean oil with polyglycerol polyricinoleate (PGPR) to stabilize the W1/O interface. The external water phase of the double emulsions was a 5mM phosphate buffer with 0.1M NaCl. Non-ionic surfactants were used as outer emulsifiers, adding sodium carboxymethylcellulose (CMCNa) that acts as thickening agent. Other food bioemulsifiers were also tested as outer stabilizer to compare the encapsulation efficiency of the double emulsions. Resveratrol concentration in the external water phase was determined by HPLC-RV using detectors of VIS/UV and fluorescence. The column used for the separation was a reversed phase column C18. The external water phase was previously recovered by centrifugation and filtration with 0.22 µm PVDF. The recovery yield of the resveratrol by this method using Tween 20 as emulsifier was 97.8 % with an encapsulation efficiency of 30 %.

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Ionic liquid-in-water emulsions for separation purposes Helene Monteillet ; F.A.M. Leermakers University of Wageningen, Laboratory of Physical Chemistry and Colloid Science, Wageningen, Netherlands

Room temperature ionic liquids are an interesting class of materials as they have a miscibility gap with water and most of the common organic solvents. We aim to use them for separation purposes, for examples to extract proteins in their native state from complex mixtures of natural molecules. To enhance the efficiency of such protocols, a large specific surface area is required; we thus aim at formulating stable and responsive ionic liquid-in-water emulsions. In this poster we present both the physical characterisation of the ionic liquid-water systems and our strategies for making such an ionic liquid-in-water emulsions. It turns out that non-ionic surfactants are good emulsifiers when the hydrophilic/lipophilic balance is properly chosen. The poster also presents information on the (in)stability of the formed emulsions.

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Nuclear proteins on the formation of DNA gel particles as controlled DNA delivery systems Maria del Carmen Moran 1; Laia Vidal 1; Joana Fortuño 1; Daniele R. Nogueira 1; Maria Pilar Vinardell 1; Maria da Graça Miguel 2; Björn Lindman 3 1Universitat de Barcelona, Departament de Fisiologia (Facultat de Farmacia), Barcelona, Spain; 2Universidade de Coimbra, Department of Chemistry, Coimbra, Portugal; 3University of Lund, Physical Chemistry 1, Lund, Sweden

A general understanding of the interactions between DNA and oppositely charged agents has given us a basis for developing novel DNA gel particles based on associative phase separation and interfacial diffusion [1]. One drawback of the DNA gel particles, in toxicological terms, is the need for a cationic compound, which may cause some cell damage. Studies in our laboratory indicate, however, that the effect of the surfactant [2] can be modulated when administered in the DNA system, rather than in an aqueous solution. While toxicity certainly applies for most classical surfactants, we are engaged in current work focusing on the particle preparation, haemocompatible and cytotoxic characterization of DNA gel particles prepared with cationic compounds with much improved intrinsic biocompatibility. These include cationic proteins such as lysozyme and protamine sulfate [3, 4]. Nuclear proteins, such as histones, have been shown to condense DNA and transfect cultured cells. Histones are also known to have nuclear localisation signals (NLS) that facilitate their nuclear import. The presence of both NLS and the positively-charged residues of lysine and arginine make them good candidates for efficient gene delivery [5]. The purpose of this work was to evaluate the physicochemical properties (particle morphology, swelling/dissolution behaviour, degree of DNA entrapment and DNA release responses) of novel histone-DNA gel particles as a function of the imposed compositions. The haemocompatible and cytotoxic assessments of the obtained particles has been determined by means of the haemolysis assay and the MTT in vitro endpoint. Acknowledgments: M.C. Morán acknowledges the support of the MICINN (Ramon y Cajal contract RyC 2099-04683) and the Project CTQ2009-14151-C02-02 from Ministerio de Ciencia e Innovación (Spain). References: [1] M. C. Morán et al., Soft Matter 2010, 6, 3143-3156. [2] M. C. Morán et al., Soft Matter 2012, 8, 3200–3211. [3] M. C. Morán et al., Langmuir 2009, 25, 10263–10270. [4] M. C. Morán et al., Small. 2012 (submitted). [5] M. Kaouass et al., J. Control Release, 2006, 113, 245–254.

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Liposomes as carriers of anti-inflammatory compounds for ophthalmic applications Monica Mosca 1; Nicola Di Matteo 2; Andrea Ceglie 1; Luigi Ambrosone 2 1Consorzio Interuniversitario per lo Sviluppo dei Sistemi a Grande Interfase (C.S.G.I.), Unità Operativa di Campobasso, Dept A.A.A., Università del Molise, Campobasso, Italy; 2Consorzio Interuniversitario per lo Sviluppo dei Sistemi a Grande Interfase (C.S.G.I.), Unità Operativa di Campobasso, Bioscience and Territory, Pesche (IS), Italy

Liposomal vesicles are promising drug delivery systems for topical administration because they are biodegradable and biocompatible nanocarriers. They can improve pharmacokinetic profile, enhance therapeutic effect, and reduce toxicity linked to higher dose. Over the last decade, market demands oriented towards natural antioxidants have fostered the research and development of new pharmaceutical ingredients from natural sources to be used as drugs antioxidants to cure skin and ocular diseases. A very promising molecule is verbascoside, a phenylpropanoid glycoside that is widely found in nature[1]. Several biological activities have been described for this compound as anti-inflammatory, antitumor, immune modulatory and antioxidative. Verbascoside is the active ingredient of anti-aging cosmetics, food supplements and feed supplement for animal breeding. In this work we have studied different liposomes made up with biocompatible lipids and a hydrophilic extract of verbascoside from a commercial food supplement. Liposomes including the functional extract were characterized by Dynamic Light Scattering and Z-Potential, to study their stability as a function of temperature and storage time [2]. Moreover, experiments of Spectrophotometry UV-Vis and Fluorimetry allowed us to determine the percentage capture, the antioxidant capacity of formulations and the oxidative behavior of different liposomal formulations. In conclusion, the results show that some preparations are stable for 1 month at 4°C and they are able to encapsulate from 36 to 63 % of verbascoside in the functional extract, depending on the lipid composition. For their stability and their complete biocompatibility, these formulations have been tested as novel pharmaceutical preparations for topic and ophthalmic use. [1].Vertuani, S., et al., Activity and stability studies of verbascoside, a novel antioxidant, in dermo cosmetic and pharmaceutical topical formulations. Molecules, 2011. 16: p. 7068-7080. [2].Mosca, M., A. Ceglie, and L. Ambrosone, Effect of membrane composition on lipid oxidation in liposomes. Chemistry and Physics of lipids, 2011. 164: p. 158-165.

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Encapsulation of B12 vitamin in concentrated double emulsion Maxime Nollet ; Véronique Schmitt CRPP, Centre of Research Paul Pascal, Pessac, France

Water-in-oil-in-water double emulsions are dispersions of an inverse emulsion in an aqueous continuous phase. These emulsions are interesting systems to encapsulate hydrophilic substances in the inner aqueous phase. Double emulsions enable a good protection of encapsulated agents against external environment, and a controlled release thereof. Despite their interest, they are still not widespread in industrial applications because of the difficulty to formulate stable systems. Indeed they require the presence of two antagonistic types of stabilizers: a more lipophilic surfactant to stabilize the inverse emulsion, and a more hydrophilic one to disperse the oil droplets in the aqueous phase. Herein, we propose to formulate a variety of highly concentrated monodisperse emulsions using different stabilizers as polymers, proteins or particles1. With B12 vitamin as model drug, we will quantify the encapsulation rate (by both UV-Visible spectrometry and rheology) just after emulsification as well as during storage. These methods allows screening various formulation and process parameters (stabilizers’ concentration, inner water volume fraction, emulsification shear rate) influencing the stability of the obtained double emulsions. The drug release can be achieved by different mechanisms as composition ripening and coalescence of the inner droplets with the oil globules. For non-stable systems, we identify the destabilization mechanisms and determine the kinetics of release combining several techniques (confocal microscopy, tensiometry, rheology, and UV-visible spectrometry). All the obtained results allow building a “stability map” for the studied systems that should guide the formulator.

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Ruthenium-based complex nanocarriers for cancer therapy Luigi Paduano 1; Gaetano Mangiapia 1; Gerardino D'errico 2; Aurel Radulescu 3; Carlo Irace 4; Daniela Montesarchio 1; Alfredo Colonna 5 1University of Naples "Federico II", Chemistry science, Naples, Italy; 2University of Naples, Naples, Italy; 3JCNS, Munich, Germany; 4University of Naples "Federico II", Dipartimento di Famacologia Sperimentale, Naples, Italy; 5University of Naples "Federico II", Farmacologia sperimentale, Naples, Italy

A new organometallic ruthenium complex, named AziRu, along with three amphiphilic nucleoside-based ruthenium complexes, ToThyRu, HoThyRu and DoHuRu, incorporating AziRu in their skeleton, have been synthesized, stabilized in POPC phospholipid formulations and studied for their antineoplastic activity. Self-aggregation behavior of these complexes was investigated, showing that the three synthesized AziRu derivatives are able to form liposomes and, under specific conditions, elongated micelles. The formulations prepared in POPC has proved to be stable for months and showed high in vitro anti-proliferative activity. Bioactivity screenings indicated that the nucleolipid Ru(III) complexes DoHuRu, HoThyRu and ToThyRu, lodged in POPC liposomes, show higher in vitro antiproliferative activities toward cancer cells of different histogenesis. This means that the three synthesized AziRu derivatives turn out to exhibit higher in vitro cytotoxicity, presumably as a result of enhanced cellular bioavailability when administered as POPC liposomes, thereby opening new perspectives in the design of innovative transition metal-based supramolecular systems for anticancer therapy.

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Thermo-breakable capsules Mathieu Destdribats ; Renal Backov ; Veronique Schmitt University of Bordeaux, Centre de Recherche Paul Pascal CNRS, Pessac, France

We propose a new synthesis pathway without any sacrificial template to prepare original monodisperse thermo-responsive capsules made of a wax core surrounded by a silica shell. Under heating, the inner wax expands and the shell breaks, leading to the liquid oil release. Such capsules that allow triggered deliverance provoked by an external stimulus belong to the class of smart materials. The process is based on the elaboration of size-controlled emulsions stabilized by particles (Pickering emulsions) exploiting the limited coalescence phenomenon. Then the emulsions are cooled down and the obtained suspensions are mineralized by the hydrolysis and condensation of a monomer at the wax-water interface, leading to the formation of capsules. The shell break and the liquid oil release are provoked by heating above the wax melting temperature. We characterize the obtained materials and examine the effect of processing parameters and heating history. By an appropriate choice of the wax, the temperature of release can easily be tuned.

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Fluorosilica particles at air-oil surfaces Bernard Binks ; Terhemen Andrew Tyowua University of Hull, Surfactant and Colloid Group, Department of Chemistry, Hull, United Kingdom

It is challenging to prepare stable materials like foams and liquid marbles from air-oil-particle systems especially if the surface tension (γ) of the oil is low (i.e. < 25 mN m-1). This is due to the fact that the adsorption of the particles at the air-oil interface is not thermodynamically favoured due to the relatively high surface energy of many particles. Nanoparticles coated with fluoroalkyl groups are promising in this regard as they possess low surface energy. The behaviour of fluoroalkyl coated silica nanoparticles (with varying degrees of fluorination) at air-oil interfaces of a wide range of oils has been studied with a view to preparing non-aqueous foams and oil liquid marbles. The contact angle (θ) (measured into the liquid) which the various liquids make with the particles is linked to the type of material obtained in these systems.

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Relaxation dynamics in an ageing glassy colloidal suspension Roberta Angelini 1; Barbara Ruzicka 1; Laura Zulian 2; Giancarlo Ruocco 3; Andrei Fluerasu 4; Anders Madsen 5 1CNR-IPCF, c/o Physics Department, University “Sapienza”, Rome, Italy; 2CNR-ISMAC, Milan, Italy; 3CNR-IPCF and Physics Department, University “Sapienza”, Rome, Italy; 4Brookhaven National Laboratory, Upton, NY, United States; 5European XFEL, Hamburg, Germany

The aging behaviour of fresh and rejuvenated glassy colloidal suspensions have been investigated by X-ray Photon Correlation Spectroscopy (XPCS) and Small Angle X-ray Scattering (SAXS). The comparison with Dynamic Light scatterin (DLS) measurements allows to distinguish two different dynamic behaviours corresponding to the so called exponential regime (DLS) and full-aging regime (XPCS) characterized respectively by an exponential growth of the relaxation time τ~ exp(atw) followed by a power law τ~ b(tw)α with α~1. In the full-aging regime the dynamic structure factor f(Q,t) is described by f(Q,t) ~ exp[-(t/τ)β]. Here for the first time we show that while the normally aged sample is dominated by a sub-diffusive dynamics as testified by the values of the stretching parameter β<1, the rejuvenated sample is dominated by a hyper-diffusive dynamics typical of systems characterized by β>1. The results are further supported by SAXS measurements which allow to distinguish between two different microscopic structures associated to the sub-diffusive and hyper diffusive dynamics. These findings shed light on a longstanding controversy in colloidal systems. A comparison with previous studies and models is also presented [1-4]. [1] R. Bandyopadhyay et al. Phys. Rev. Lett. 93, 28302 (2004). [2] L. Cipelletti et al. Phys. Rev. Lett. 84, 2275 (2000). [3] M. Bellour et al. Phys. Rev. E 67, 031405 (2003). [4] F. Schosseler et al. Phys. Rev. E. 73, 021401 (2006).

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Influence of charge density on bilayer bending rigidity in lipid vesicles: a combined dynamic light scattering and neutron spin-echo study Beate-Annette Brüning 1; Ralf Stehle 1; Peter Falus 2; Bela Farago 2 1Helmholtz Zentrum Berlin, Berlin, Germany; 2Institut Laue Langevin, Grenoble, France

Liposomes composed of cationic lipid mixtures have been found effective vehicles for cellular drug delivery [1], as well as gene transfection applications [2]. In this context, a detailed understanding of the changes induced in model vesicles by the insertion of charged lipids is crucial to exploit their potential as targeted carriers. We report a combined dynamic light scattering and neutron spin-echo study on vesicles composed of the uncharged helper lipid 1,2-dimyristoyl-sn-glycero-3-phosphatidylcholine (DMPC) and the cationic lipid 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP). We compare the bilayer undulation dynamics in DMPC/DOTAP lipid vesicles to vesicles composed of a mixture of the uncharged helper lipid DMPC with the also uncharged reference lipid 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC). We have performed dynamic light scattering on both types of lipid mixtures to investigate changes in vesicle size and mass diffusion. We study bilayer undulation and bulk diffusion dynamics using neutron spin-echo spectroscopy on two distinct time scales, namely around 25 ns and 150 ns. Finally, we calculate the respective bilayer bending rigidities for both types of lipid vesicles [3]. We find, that on the local length scale the insertion of lipid headgroup charge influences the bilayer undulation dynamics and bilayer bending rigidity less than inserting lipids with acyl chain unsaturation: We observe a bilayer softening with increasing inhomogenity of the lipid mixture, which we link to a hydrophobic mismatch between the acyl chains of the respective lipid components, evoking a lateral phase segregation in the membrane plane. [1] R. B. Campbell, S. V. Balasubramanian, R. M. Straubinger, J. Pharm. Sci., 90, 1091 (2001). [2] N. J. Zuidam, Y. Barenholz, Biochim. Biophys. Acta., 1368, 115 (1998). [3] B. Brüning, R. Stehle, P. Falus, B. Farago, in preparation.

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Fluctuation dynamics in unilamellar phospholipid vesicles: Influence of temperature, cholesterol and trehalose Beate-Annette Brüning 1; Sylvain Prévost 2; Ralf Stehle 3; Roland Steitz 1; Peter Falus 4; Thomas Hellweg 5 1Helmholtz Zentrum Berlin, Berlin, Germany; 2Technische Universität Berlin, Berlin, Germany; 3Universität Bayreuth, Bayreuth, Germany; 4Institut Laue Langevin, Grenoble, France; 5Universität Bielefeld, Bielefeld, Germany

We report a combined dynamic light scattering (DLS) and neutron spin-echo (NSE) study on lipid vesicles composed of 1,2-dimyristoyl-sn-glycero-3-phosphatidylcholine (DMPC), respectively under the influence of temperature and the membrane additives cholesterol and trehalose. Mechanical properties of a model membrane and thus the corresponding bilayer undulation dynamics can be specifically tuned by changing its lipid headgroup or acyl chain properties through temperature or composition [1]. A structural characterization of the respective model systems at varied phase state was performed to investigate lipid vesicle size and polydispersity. We have performed dynamic light scattering on the lipid (mixtures) to investigate changes in vesicle size and mass diffusion. We study bilayer undulation and bulk diffusion dynamics using neutron spin-echo spectroscopy, on two distinct time scales, namely around 25 ns and 100 ns. Finally, we calculate the respective bilayer bending rigidities for all types of lipid vesicles. We find, that on the local length scale changes at the lipid headgroup influence the bilayer undulation dynamics and bilayer bending rigidity less than at the lipid acyl chain: We observe a bilayer softening around the main phase transition temperature Tm of the single lipid model system, and a bilayer stiffening the more cholesterol is added, whereas the insertion of trehalose hardly changes the bilayer undulations and membrane rigidity [2]. We explain our findings on the basis of a free volume available to lipid molecules in the membrane plane, which encounters the most pronounced changes in the acyl chain regime. References: [1] B. Brüning, R. Stehle, P. Falus, B. Farago, submitted. [2] B. Brüning, S. Prévost, R. Stehle, R. Steitz, P. Falus, T. Hellweg, in preparation.

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Viscosity oscillations in a lamellar phase system Luigi Gentile 1; Bruno F.B. Silva 2; Joachim Kohlbrecher 3; Kell Mortensen 4; Ulf Olsson 2 1University of Calabria, Rende (CS), Italy; 2Lund University, Lund, Sweden; 3Paul Scherrer Institut, Villigen, Switzerland; 4University of Copenhagen, Frederiksberg, Denmark

Complex fluids may be affected by the flow field due to interrelation between flow and structure. Here, we have studied viscosity oscillations caused by structural changes in a nonionic lamellar phase, namely shear-Induced Multilamellar Vesicles (MLVs). Even though viscosity oscillations have been found in some shear-induced wormlike micelles (WMs), this phenomenon is very uncommon in lamellar phase (Lα) systems. Through rheological measurements we find that the viscosity oscillation can be described by a sinusoidal wave with a period of c.a. 19 minutes. Using in-situ rheo-small angle neutron scattering (SANS) we were able to associate the viscosity behavior with the fraction of MLVs and planar lamellae. In addition to the general interest in viscosity oscillation phenomena, the obtained results help us to further understand the relation between MLV formation and the “bulk” viscosity.

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Improved magnetic properties of iron oxide nanoparticles for magnetic resonance imaging by post-synthesis oxidation and surface-modification Christina Graf 1; Patrick Stumpf 1; Eugen Weschke 2; Christine Boeglin 3; Frithjof Nolting 4; Hendrik Ronneburg 1; Eckart Rühl 1 1Freie Universität Berlin, Berlin, Germany; 2Helmholtz-Zentrum Berlin für Materialien und Energie, Berlin, Germany; 3Institut de Physique et de Chimie de Strasbourg Département Surfaces-Interfaces, Strasbourg, France; 4Paul Scherrer Institut, Swiss Light Source, Villigen, Switzerland

Iron oxide (FeOx) nanoparticles are applied in medicine as contrast agents in magnetic resonance imaging (MRI) where they reduce the spin-spin relaxation time of absorbing tissue. Hence, a control of their magnetic properties is essential for these applications. These properties strongly depend on the particle size, and shape, as well as the surface structure and the modification of the iron oxide core. Therefore, monodisperse, spherical iron oxide (Fe3O4/Fe2O3) nanoparticles were prepared by a high temperature approach in organic solvents using iron oleate as precursor. After the synthesis the particles are tempered in O2-free or O2-rich environment to improve their crystalline order and to change their magnetite to maghemite ratio. Near Edge X-Ray Absorption Fine Structure (NEXAFS) and X-Ray Magnetic Circular Dichroism (XMCD) are used to investigate local magnetic and electronic properties of the particles before and after the post-synthetic treatment. The XMCD measurements show that both, the magnetization of the nanoparticles as well as their magnetite to maghemite ratio, are strongly increased after tempering in an oxidative environment which likely causes rearrangement of their crystalline order. The magnitude and the kinetics of this effect strongly depend on the particle size. Further, we investigate if a functionalization of the nanoparticles with a polyethylene glycol bisphosphonate ligand also influences their local magnetic properties. This functionalization is relevant, as it renders the initially hydrophobic nanoparticles hydrophilic which is mandatory for medical application. XMCD measurements show that the functionalization with these ligands has a similar effect as thermal oxidation, i. e. the magnetization and the maghemite content are increased. Subsequent transfer of the particles in aqueous media further increases these processes.

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Gold nanocrystal superlattices: a small angle neutron scattering study Matthias Karg University of Bayreuth, Physical Chemistry, Bayreuth, Germany

The assembly of metal nanoparticles into superstructures with mm or even cm dimensions is a rather challenging scientific task. Despite the high quantity of monodisperse nanoparticles needed, the loss of colloidal stability is a major limitation to be overcome. We coated gold nanocrystals with homogeneous cross-linked polymer shells resulting in core-shell hybrid particles with well-defined structures [1]. The polymer shells are composed of poly-N-isopropylacrylamide (PNIPAM), which is a thermoresponsive material. Due to the addition of this polymer shell, the effective particle volume of the nanoparticles is increased significantly. This allows reaching high particle volume fractions with a comparably low particle number. Crystallization of these hybrid particles was observed over a broad range of particle concentrations at (and below) room temperature [2]. Upon an increase in temperature, the PNIPAM shells shrink and the overall particle volume fraction decreases. This causes melting of the crystals in a certain concentration range. Upon cooling, crystallization occurs again, once a critical volume fraction is reached. These melting/recrystallization processes were observed to occur with very high reproducibility as will be demonstrated in this contribution. Structural insights of the superlattices were obtained using Small Angle Neutron Scattering (SANS). At low concentrations, where inter-particle interactions can be neglected, the particle form factor P(Q) was determined. In contrast, the scattering profiles for crystalline samples contain information on P(Q) as well as on the structure factor S(Q). Scattering profiles were recorded and analyzed for a broad range of concentrations and a variety of temperatures to study the melting behavior of the superlattices. [1] M. Karg, S. Jaber, T. Hellweg, P. Mulvaney, Langmuir 2011, 27, 820-827 [2] M. Karg, T. Hellweg, P. Mulvaney, Adv. Funct. Mater. 2011, 21, 4668-4676

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X-ray reflectivity and grazing-incident X-ray scattering studies on mixed thiolated-gold nanoparticle/lipid monolayer Tsang-Lang Lin 1; Yi-Tang Chen 1; Chin-Hua Hung 1; Yuan Hu 1; Ming-Tao Lee 2; U-Ser Jeng 2 1National Tsing Hua University, Department of Engineering and System Science, Hsinchu, Taiwan; 2National Synchrotron Radiation Research Center, Hsinchu, Taiwan

We characterize the nanostructures of Langmuir monolayer of thiolated-gold nanoparticles mixed with amphiphilic molecules such as surfactants, and lipids by X-ray reflectivity, grazing-incident scattering methods, and transmission electron microscopy (TEM). We synthesized gold nanoparticles with an average diameter of 1.8 nm, and the gold nanoparticles are protected with octanethiol or hexadecanethiol molecules. The monolayers are transferred onto silicon wafers for X-ray analysis and onto copper grid for TEM analysis. For Au-hexadecanethiol nanoparticles, they form monoalyers with monoclinic lattice structure as indicated by the ratio of the two broad diffraction peaks respectively centered at scattering vector Q= 0.165 and 0.243 1/Å. As for the Au-octanethiol nanoparticles, the grazing-incident scattering pattern shows only one broad diffraction peak centered at Q= 0.253 1/Å. The structural order is affected by the size of the gold nanoparticle as well as the chain length of the thiol molecules. For the mixed Au-octanethiol nanoparticle/DPPC lipid monolayer system, at low compression pressure, the Au-octanethiol nanoparticles form a monolayer on top of disordered lipid molecules. When the surface pressure is increased, ordered lipid monolayer is formed and the Au-octanethiol nanoparticle monolayer is supported by the lipid monolayer as revealed by the X-ray reflectivity measurement. It is favorable for the hydrophobic thiolated gold nanoparticles to sit on the hydrophobic lipid tails instead of staying on the water surface. It seems that thiolated gold nanoparticles have strong affinity to form large closely packed domains on smooth surface and it is not easy to disperse the thiolated gold nanoparticles into isolated ones on a surface. It is found that the presence of sudium dodecyl sulfate (SDS) could disperse the originally large Au-octanethiol/DPPC domains into thread-like domains. It is also found that the addition of SDS could increase the distance between the neighboring Au-octanethiol nanoparticles which indicates that SDS could be inserted between the Au-octanethiol nanparticles to change the interface interactions.

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Soft matter in the subzero degree Celsius regime: studying frozen food with x-ray phase contrast tomography Annabelle Medebach 1; Bernd Rupert Pinzer 1; Cedric Dubois 2; Hans Jorg Limbach 2; Martin Schneebeli 3; Marco Stampanoni 1 1Paul Scherrer Institute, Swiss Light Source, Villigen PSI, Switzerland; 2Nestle Research Center, Department of Food Science and Technology, Lausanne, Switzerland; 3WSL Institute for Snow and Avalanche Research SLF, Snow and Permafrost, Davos Dorf, Switzerland

The microstructure as well as the components of composite materials influence the properties of the material. The microstructure itself is influenced by the manufacturing process. In the case of food the microstructure impacts the sensory perception. The interactions within this complex system are not yet completely understood due to the vast variety of ingredients and interactions spanning large time and length scales involved. To complement the traditionally used imaging techniques, synchrotron x-ray tomographic microscopy can provide direct information about the microstructure in a non-invasive way at a high spatial and temporal resolution. To study the microstructure of frozen food and its evolution a new sample environment at the TOMCAT beamline at the Swiss Light Source has been taken into operation. We present the new sample environment that allows for in-situ experiments under controlled thermal conditions between -40°C and 0°C with a stability of less than ±0.1°C. The sample environment allows for time lapse studies, in particular the investigation of structural changes due to heat shocks. The benefits of using x-ray tomography on ice cream samples enriched with a contrast agent has been shown before (1). Propagation based phase contrast imaging (PCI) at a synchrotron allows for the differentiation of similarly absorbing materials like sucrose solution and ice crystals without the addition of contrast agents. We present first results regarding the structural characterization and evolution of ice cream obtained with PCI under constant thermal boundary conditions. In particular we study non-equilibrium Ostwald-ripening and coalescence of the air cells and the ice crystals. Fat aggregates have so far not been observed. The experiments will provide insight into the fundamental physics behind coarsening and other evolutionary effects of the micro structure. (1) Pinzer, B. R., Medebach, A., Limbach, H. J., Dubois, C., Stampanoni, M., & Schneebeli, M. (2012). 3D-characterization of three-phase systems using X-ray tomography: tracking the microstructural evolution in ice cream. Soft Matter, 8(17), 4584-4594.

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Structure and dynamics of large hydrophobic ions in concentrated aqueous solutions Debsindhu Bhowmik 1; Natalie Malikova 1; Guillaume Meriguet 2; Olivier Bernard 2; Jose Teixeira 1; Pierre Turq 2 1CEA Saclay, Laboratoire Leon Brillouin, Gif-sur-Yvette, France; 2UPMC (Univ. Paris 6), PECSA, Paris, France

Tetrabutylammonium, beyond its application as a phase transfer catalyst due to its large solubility either in water or organic solvents, has been the subject of investigations for long due to its antagonist ionic and hydrophobic features. The present study examines the result of the balance between the hydrophobic and electrostatic effects on the structural and the dynamical properties of concentrated solutions. For that purpose, molecular dynamics simulations of tetrabutylammonium bromide solutions have been carried out in close connection with static and quasi-elastic neutron scattering experiments. Computed scattered intensities and intermediate scattering functions I(Q,t) will be discussed together with experimental ones. The cation-cation correlation is found to be unexpectedly small even for concentrated (around 1 mol L-1 ) solutions, which suggests a compensation of the electrostatic interaction between cations. No cation-cation aggregation due to hydrophobic effect is observed. The tetrabutylammonium cation appears to be highly solvated and its hydrocarbon arms are almost fully stretched. The internal and global dynamics are probed at the molecular scale either by molecular dynamics or neutron scattering. A strong decrease of the translational diffusion coefficient is detected. Finally, as the tetrabutylammonium diameter (~ 1 nm) places it at the lower boundary of the colloidal domain, the limits of validity of such a description will be discussed in the light of the previous results.

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Calcite crystallisation in the presence of biopolymers: A neutron reflection study Kathryn Miller 1; Seung Yeon Lee 1; Rebecca Welbourn 1; Maximilian Skoda 2; Christian Kinane 2; Stuart Clarke 1 1University of Cambridge, BP Institute, Cambridge, United Kingdom; 2ISIS, Rutherford Appleton Laboratory, Didcot, United Kingdom

Here we report the first molecular level adsorption study of heparin on calcite using neutron reflection. Our intention is to address how these species influence biomineralisation and the inhibition of mineral crystallisation. Calcium carbonate crystallisation in nature produces intricate and complex crystal structures through subtle control of crystal polymorphs. Organic molecules are interspersed through polycrystalline media affecting both growth rates and mechanical stability. Biopolymers have also been shown to inhibit or slow the growth of calcite crystals in egg formation allowing the embryo to develop before calcification of the shell. This effect can be exploited to stop limescale formation, a problem experienced both industrially and in the home. Heparin, a non-hazardous sugar, can be added to water in very low quantities to inhibit scale formation. Understanding how this works can help to design more efficient inhibitor molecules. Previous work suggests that heparin specifically adsorbs to the calcite stable crystal face, dramatically reducing the effective crystal growth area. This effect is enhanced after incubation of seed crystals with heparin before transfer to a crystallisation medium. This clearly suggests an adsorption mechanism for the inhibition. Neutron Reflection of calcite is a technique which has not previously been used to study biopolymer interactions of this kind. It is a sensitive technique to study the density and structure of layers at interfaces and therefore very powerful for investigating this particular system directly. Our initial experiments have shown a highly hydrated diffuse polymer layer which would easily allow ion transport to the crystal surface. Sulphate groups on molecules are reported to increase the adsorption to calcite due to the high affinity with calcium ions. In this work, the role of the sulphate groups on the molecule has been examined directly by the study of both sulphated and de-N-sulphated heparin molecules. By removing 1/3rd of the sulphate groups we find that the adsorption is essentially switched off supporting the model that sulphated molecules have a high affinity for the calcite surface

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Nucleolipid bilayers: a neutron reflectometry and QCM study Costanza Montis 1; Giovanna Fragneto 2; Tommy Nylander 3; Piero Baglioni 1; Debora Berti 1 1University of Florence and CSGI, Department of Chemistry, Firenze, Italy; 2Institut Laue-Langevin, Grenoble, France; 3Lund University, Department of Chemistry, Lund, Sweden

Nucleolipids are bio-inspired amphiphiles with a phospholipid backbone and nucleoside polar head. Thanks to the nucleoside head they facilitate specific interactions between the polar head and DNA. They can therefore trigger complex formation with nucleic acids with molecular recognition. They have therefore scientific interest for the development of novel DNA vectors. This study aims to reveal how the nucleobase units affect the structure of the bilayer and specific interaction with nucleic acids. Mixed lipid bilayers from the anionic nucleolipid POP-Ade (1-Palmitoyl-2-oleoyl-sn-glycero-3-phosphatidyladenosine) with POPC (1-Palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine) were prepared on sapphire and silica supports both through a Langmuir-Blodgett and a vesicle fusion technique and characterized by QCM and Neutron Reflectometry. In order to highlight the effect of nucleic polar headgroup on membrane structure and interaction, the experimental results were compared with those obtained for the same systems with the phospholipid POPG (1-Palmitoyl-2-oleoyl-sn-glycero-3-phosphatidylglycerol), substituting POP-Ade. The interaction between the supported bilayers and ss- and ds- nucleic acids mediated by Ca2+ was then investigated. A specific interaction between POP-Ade polar head and polyU (poluridylic acid) was found to drive polyU binding to POP-Ade membranes. Moreover, the association was stronger with polyU (with A-U Watson-Crick complementary bases in RNA) with respect to polyA, highlighting hence a specificity in the interaction between nucleolipid membranes and polynucleotides. The association of ds-DNA to POP-Ade was significantly different from the interaction with POPG bilayers, showing that the nucleolipid polar headgroup indeed have molecular recognition capability.

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Effect of adsorbed polyelectrolytes with different degree of polymerization on lipid monolayers between fluid and solid state Jens-Uwe Günther ; Heiko Ahrens ; Thomas Ortmann ; Christiane A. Helm Greifswald University, Greifswald, Germany

Electrostatic and entropic interactions in monolayers of dioctadecyldimethyl-ammonium bromide (DODA) with adsorbed Polystyrene sulfonate (PSS) are studied by isotherms, Grazing Incidence Diffraction and X-ray reflectivity. The polymer concentration is kept constant with respect to the monomer concentration (0.01 mM). PSS adsorbs flatly, the surface coverage is controlled by the lipid molecular area and can be varied by a factor of two. The PSS polymer molecular weight has very little influence on the surface coverage. However, on increase of the polymer weight the lipid phase transition pressure decreases, until it levels off. Constant and low phase transition pressure is observed when the PSS contour length exceeds the persistence length. Therefore, the solidification is attributed to the immobilization of lipids by one large stiff rod of increasing length. A subtle effect due to entropic interactions is the non-monotonic polymer weight dependence of the monolayer phase transition enthalpy. A maximum occurs at 6.5 kDa. The maximum can be explained by the different phases of adsorbed PSS. The X-ray techniques show that PSS adsorbs to the lipids in the solid phase as two-dimensional lamellar rods. Yet, PSS adsorbs to fluid lipids in the two-dimensional lamellar phase only for polymer weights above 6.5 kDa. For smaller polymer weight, it adsorbs to the fluid monolayer as disordered sticks. Then, the fluid/solid transition of the lipids and the disordered / ordered transition of the PSS occur simultaneously. In this special case, the transition enthalpy increases with the PSS molecular weight.

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Equation of state and structure of highly concentrated globular protein solutions Coralie Pasquier 1; Sylvie Beaufils 2; Antoine Bouchoux 1; Bernard Cabane 3; Sophie Rigault 1; Javier Perez 4; Valérie Lechevalier 5; Cécile Le Floch-Fouéré 5; Gilles Paboeuf 2; Maryvonne Pasco 5; Stéphane Pezennec 1 1INRA, UMR1253 STLO, Rennes, France; 2CNRS, UMR6251 IPR, Rennes, France; 3CNRS, UMR7636 PMMH, Paris, France; 4Synchrotron SOLEIL, SWING, Gif sur Yvette, France; 5Agrocampus Ouest, UMR1253 STLO, Rennes, France

In food technology, proteins are classically subject to operations leading to high local concentrations (membrane filtration, drying, stabilization of dispersed systems through the formation of dense interfacial films). However, few studies have for now been conducted on the behaviour of globular proteins in “highly crowded” situations, despite interesting observations in some cases and a growing interest in the subject [1,2]. Our goal is to study the crowding of proteins in an extended concentration range, up to volume fractions about 0.5, using highly concentrated solutions obtained via the osmotic stress method [3]. Recently, this method has been used to study the behaviour of milk casein micelles upon concentration [4]. Equations of state, which relate concentration and osmotic pressure, were established for two well-known globular proteins, lysozyme and ovalbumin, in different charge and ionic strength conditions. We then conducted a SAXS study of the structure of the highly concentrated lysozyme and ovalbumin samples. We showed that the structure of the samples, depending on the protein, the charge and the range of interactions, underwent drastic structural changes and phase transitions upon concentration. In this communication, we will discuss the equations of state obtained for lysozyme and ovalbumin, then the structural properties of crowded lysozyme and ovalbumin as determined by SAXS studies, in the light of the molecular structure and physico-chemical properties of these two proteins, as well as the general behaviour and interaction properties of proteins. [1] A. Stradner, H. Sedgwick, F. Cardinaux, W.C. Poon, S.U. Egelhaaf and P. Schurtenberger, Nature, 2004, 432, 492-495 [2] A. Shukla, E. Mylonas, E.D. Cola, S. Finet, P. Timmins, T. Narayanan and D.I. Svergun, Proc. Nat. Acad. Sci., 2008, 105, 5075-5080 [3] V.A. Parsegian, N. Fuller and R.P. Rand., Proc. Nat. Acad. Sci., 1979, 76, 2750-2754. [4] A. Bouchoux, G. Gesan-Guiziou, J. Perez and B. Cabane, Biophys. J., 2010, 99, 3754-3762

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Deposition from AAm/MAPTAC SDS formulations on hydrophobised and hydrophilic silica – how composition and deposition are affected by dilution and co-deposants Asger B. Petersen 1; Eric S. Johnson 2; Lennart Piculell 3; Tommy Nylander 3 1Lund University, Physical Chemistry, Lund, Sweden; 2P&G Beauty & Grooming, Cincinnati, United States; 3Lund University, Physical Chemsitry, Lund, Sweden

Formulations in pharmaceutics, and personal care products often contain cationic polymers (polyions, PIs), anionic surfactants (surfactant ions, SIs), and silicone emulsions. The silicone emulsions are added to modify surface properties and improve the feel of the skin and hair treated with the product. In aqueous systems consisting of oppositely charged PI/SI mixtures there is an onset of the SI binding to PI called the critical aggregation concentration (cac) where SI micelles start to form at the PIs. The SI cac is usually lower than the critical micelle concentration (cmc) of the SI alone, and is affected by the PI concentration, charge density, hydrophobicity, and flexibility. This SI binding is typically accompanied by associative phase separation. For some systems a further increase in SI concentration results in a second cooperative binding step, leading to a resolubilisation of the complexes, at a second critical association concentration (cac(2)). The present study focuses on the actual composition of the deposited layer(s) from a PI/SI formulation initially above cac(2) on hydrophobised and hydrophilic surfaces before and after dilution. The dilution mimics the deposition by rinsing protocol used in applications such as shampoo. Earlier work in the group lead us to chose a formulation comprising of poly(acrylamide/methacrylamidopropyl trimethylammonium chloride) (AAm/MAPTAC) as the PI and sodium dodecyl sulfate (SDS) the SI with a concentration above cac(2). A commercially available silicone emulsion was chosen for formulations containing surfactant stabilised hydrophobic silicone droplets, and hydrophilic colloidal silica particles of similar size were chosen for comparison. On this poster we discuss the structure and composition of mixed PI/SI layer(s) deposited on hydrophobised and hydrophilic silica under aqueous conditions that resemble rinsing protocols for testing shampoo formulations. The depositions before and after rinsing were investigated with neutron reflectometry and ellipsometry. We found that formulations with high ratios of silicone oil emulsion or colloidal silica significantly lowered the deposition of material on the surface.

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Synchrotron Scattering Techniques for Industrial Applications Diego Pontoni ; Manfred Burghammer ; Oleg Konovalov ; Edward Mitchell ; Theyencheri Narayanan ; Michael Sztucki ; Alexei Vorobiev European Synchrotron Radiation Facility, Grenoble, France

The European Synchrotron Radiation Facility is pursuing an ambitious Upgrade programme whose objectives include further enhancement of user support in the field of applied soft materials. New infrastructure such as the Partnership for Soft Condensed Matter and the Technology Platform will provide complementary sample characterisation capabilities allowing optimal preparation of cutting-edge synchrotron X-ray experiments. This poster illustrates the state-of-the-art performance of various synchrotron scattering techniques for the nanoscale characterisation of soft materials bearing industrial relevance. The high detection capability of simultaneous small and wide angle X-ray scattering (SAXS/WAXS) in probing shape changes and bilayer phase transitions in surfactant systems is demonstrated by the investigation of dilute suspensions of DODAB unilamellar vesicles [1]. The unique capability of X-ray reflectivity and grazing incidence diffraction in revealing the nanoscale structure and complexity of liquid surfaces is highlighted by the study of water-based ferrofluids [2]. Finally, the power of scanning microbeam SAXS/WAXS is exemplified by the detection of calcium carbonate mineralisation at the surface of evaporating solution droplets deposited on super-hydrophobic surfaces [3]. The ESRF is a world-leading synchrotron light source and encourages industrially relevant research both via collaborations and partnerships with industry, as well as via proprietary access. [1] P. Saveyn et al., Soft Matter 5,1735,2009 [2] A. Vorobiev et al., J. Appl. Phys. 110, 102219,2011 [3] A. Accardo et al., Langmuir 27, 8216, 2011

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Modelling phospholipid stabilized dispersions of colloidal crystals by means of small angle x-ray and neutron scattering Martin Schmiele ; Tobias Unruh Friedrich-Alexander University Erlangen-Nuremberg, Crystallography and Structure Physics, Erlangen, Germany

In modern pharmaceutical research dispersions of triglyceride solid lipid nanoparticles are studied as a promising drug delivery system [1]. Our group focuses on dispersions of tripalmitin nanocrystals that are stabilized by well-tolerated phospholipids and bile salts in an aqueous dispersion medium. These dispersions can be considered as a representative model for many similar colloidal dispersions intended as a potential drug delivery system. Understanding the molecular arrangement of the phospholipids at the interface between the tripalmitin core and the aqueous phase is crucial to comprehend the nanoparticle's stabilization mechanism but also to control drug encapsulation. However, up to now the knowledge about the structural arrangement of the phospholipid molecules in the stabilizer layer is rather vague. Numerous software packages do exist for the simulation of small angle scattering patterns of dispersions of homogeneous nanoparticles. Basically, they all rely on the calculation of the particle form factor. However, tripalmitin and other (organic) nanocrystals that possess long crystallographic c-axes give rise to Bragg peaks in the small angle range. Interestingly, in a previous SAXS study it turned out that tripalmitin's 001-Bragg reflection is very sensitive on the stabilizer layer what can be utilized to resolve their structure [2]. The existing simulation routines can take Bragg reflections into account solely by heuristic models for their peak profiles. To remedy this shortcoming and to compute the small angle scattering patterns from colloidal crystal dispersions the "X-Ray Powder Pattern Simulation Analysis" method has been developed [2] and extended for neutron scattering. It facilitates the computation of the small angle and Bragg scattering contributions directly from a statistical particle model and the crystal's and stabilizer layer's geometry. [1] H. Bunjes. Structural properties of solid lipid based colloidal drug delivery systems. Curr. Opin. Colloid & Interface Sci., 16, 405–411 (2011) [2] T. Unruh. Interpretation of SAXS patterns of crystalline triglyceride nanoparticles in dispersion. J. Appl. Cryst., 40, 1008-1018 (2007)

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Small-angle neutron scattering (SANS) as a tool to study charging in nonpolar liquids Gregory Smith 1; Julian Eastoe 1; Roger Kemp 2 1University of Bristol, School of Chemistry, Bristol, United Kingdom; 2Merck Chemicals Ltd, Southampton, United Kingdom

The formation of charged species in nonpolar liquids is important for applications such the electrophoretic displays used as electronic paper in e-Reader devices. Unlike in water, in nonpolar solvents, aggregate structures, such as surfactant inverse micelles, are required to stabilize charge. Small-angle neutron scattering (SANS) is a powerful tool that can be used to obtain important structural information about the components in these charged systems. It has been employed to understand how the structure of inverse micelles changes with concentration and whether inverse micelles form at a single concentration, as in aqueous systems, or not. The existence of a critical micelle concentration (CMC) for the formation of inverse micelles in nonpolar fluids is an unresolved question in colloid science and is also important in determining the concentrations of surfactant required in display applications. Contrast-variation SANS experiments have been devised to determine the location of surfactant molecules when charging colloids, whether on the surface or in the bulk, by using systematic isotopic labelling of H and D. This will not only provide a deeper understanding of the mechanism behind charge formation in nonpolar solvents but will also enable more effective surfactants to be designed.

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NREX Neutron/x-ray contrast reflectometer Olaf Soltwedel ; Yury Khaydukov ; Thomas Keller Max Planck Institute For Solid State Physics, Stuttgart, Germany

NREX is a classical angle dispersive, fixed wavelength reflectometer at the cold neutron source of the FRM II in Garching/Munich. It is operated by the Max Planck Society. The instrument provides grazing incidence small angle scattering (GISANS), specular and off specular reflectometry all in polarized and non-polarized modes. This techniques are well suited to determine structural properties such as chemical aggregation, polymer and surfactant adsorption, interdigitation etc. in low dimensions (surfaces, interfaces and thin film systems) at solid/liquid - and solid/air interfaces. With a conventional x-ray add on (Cu-Kα), the instrument offers the unique possibility to combine x-ray- and neutron-reflectometry in situ. The resent developments, exemplary measurements and future perspectives of NREX will be presented.

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Dynamical heterogeneities in phospholipid membranes Sebastian Busch 1; Tobias Unruh 2 1University of Oxford, Biochemistry, Oxford, United Kingdom; 2Friedrich-Alexander-Universität Erlangen-Nürnberg, Physik, Erlangen, Germany

Phospholipids are the main constituent of biological membranes. They are also used as stabilizers for emulsions and suspensions and form the main component of vesicular formulations. All of these systems have a variety of applications, for example in the pharmaceutical industry. Taking into account that the molecular dynamics of the phospholipid molecules is accepted to reflect significant properties of the stabilizing membrane with respect to permeability for molecules, interaction with molecules such as proteins and the stabilizing properties for emulsions and suspensions, it is surprising that it is not yet understood in detail. Against this background we studied the picosecond dynamics of phospholipid molecules in multibi-, bi- and monolayers with and without additives. A comprehensive overview of the various experimental results extracted from quasielastic neutron scattering (QENS) studies will be presented. For the liquid crystalline phase of dimyristoylphosphatidylcholine the mechanism of the lateral long-range motion of the molecules was found to be not diffusive but flow-like. These collective motions can be interpreted in terms of a general feature of dense systems known as dynamical heterogeneities. Simple structural models allow the understanding of the influence of additives on the phospholipid dynamics. The dynamics of phospholipid molecules in monolayers as in the stabilizing layer of emulsion droplets was found to be determined mainly by their packing density.

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Self-assembly of cationic surfactant and block copolymers in protic ionic liquids Norman Wagner ; Carlos Lopez-Barron University of Delaware, Newark, United States

In this work we study self-assembly and the structure-rheological properties relationships of amphiphilic Pluronic block copolymers (triblock copolymers made of a central polypropylene oxide (PO) and two end polyethylene oxide (EO) blocks) dissolved in a protic ionic liquid (ethylammonium nitrate, EAN). Using a combination of experimental methods including rheology, cross-polarized light microscopy, and small angle neutron scattering, we characterized the phase diagram of the Pluronic/IL model system: F127 (EO106PO70EO106)/EAN and L121(EO5PO70EO5)/EAN. The length of the EO block has a significant effect on the shear viscosity and elastic modulus of the micellar aggregates. Spherical micelles are formed for higher Mw EO blocks, which stabilizes the highly curved spherical interface. For lower EO Mw steric effects are less significant and the interface curvature is lowered, forming cylindrical (wormlike) micellar aggregates. Spherical micellar solutions behave as non-birefringent Newtonian liquids whereas wormlike micelles show a considerable viscoelasticity and strong flow birefringence. A comparison with pluronic self-assembly in water is interpreted with molecular thermodynamics, providing guidance for the self-assembly of non-ionic surfactants and block copolymers in ionic liquids The self-assembly of didodecyldimethylammonium bromide (DDAB) in a protic ionic liquid, ethylammonium nitrate (EAN), in the high concentration regime, is studied using five different experimental techniques. A thermo-reversible first order sponge (L3) to lamellar (La ) transition occurring at [DDAB] > 80 wt% was evidenced by (1) a sharp increase in the elastic and viscous moduli, (2) a transition peak recorded by differential scanning calorimetry, (3) formation of Maltese cross birefringence textures observed via polarizing optical microscopy, (4) a decrease in the inter-bilayer mean distance measured by small angle neutron scattering and (5) an abrupt increase in the conductivity obstruction factor. In contrast to aqueous DDAB solutions, this surfactant forms a stable L3 phase in EAN in a wide window of compositions and temperatures.

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Functional group dependence of lubrication additive behaviour Rebecca Welbourn 1; Stuart Clarke 1; Ian Collins 2; Ali Zarbakhsh 3 1University of Cambridge, Chemistry, Cambridge, United Kingdom; 2BP (UK), Sunbury, United Kingdom; 3Queen Mary, University of London, Chemistry, London, United Kingdom

Here we present a comparison of phosphate and sulphonate group adsorption at a model metal oxide surface, to aid the understanding of additives used in lubrication. The mechanisms of adsorption of organic molecules at the metal/liquid interface (chemisorption and physisorption) are of paramount importance for understanding the principles of many surface interactions, such as for lubrication or cooling. The surface selectivity of the adsorbate compounds can be controlled by tuning properties such as alkyl chain length, functional groups, polarity and solubility. This creates the possibility of producing ‘designer’ additives. Phosphates are extensively used in lubrication and understanding their adsorption behaviour is key to furthering this research. Here we draw a direct comparison of phosphates to sulphonates, another functional group widely used in lubrication. Metals are central to lubrication research, because of their frequent use in close contact environments, often at high temperatures and pressures. A good example of this is aluminium: an essential material in many industries, such as aviation, construction and packaging. This work uses aluminium oxide (α-alumina) as a model for the natural surface oxide formed on aluminium metal. This model has limitations arising from the differences in crystal structure of alumina to the natural oxide. Therefore, this study is extended to the aluminium metal surface (terminated by a natural oxide layer) to offer a comparison of adsorption at these two oxide surfaces. Through lab-based solution studies and neutron reflection experiments, the adsorption of the sulphonate surfactant aerosol-OT (AOT) and its phosphate analogue sodium bis-(2-ethylhexyl)phosphate (NaDEHP) has been observed and compared. Here these results from the alumina/liquid interface are presented and compared to the first neutron reflection studies from the aluminium metal/liquid interface.

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A neutron spin-echo study of membrane dynamics in disconnected lamellar phases Stefan Wellert 1; Matthias Karg 2; Lukas Szymanski 3; Cosima Stubenrauch 3 1TU Berlin, Berlin, Germany; 2University of Bayreuth, Bayreuth, Germany; 3University of Stuttgart, Stuttgart, Germany

This contribution discusses the results of a neutron spin-echo (NSE) experiment addressing the dynamics in disconnected lamellar phases. The binary water-surfactant systems D2O-C12E5, D2O-C12E6 and the pseudobinary system D2O-C12E5/C12E6 were investigated. The combination of a surfactant forming a continuous lamellar phase extending to low surfactant concentrations with a surfactant forming a lamellar phase only at high concentrations results in a disconnected lamellar phase. Regarding the stabilization of the lamellar phase in the dilute and the concentrated regime, respectively, it is known that the dilute lamellar phases, where the interlamellar distances are larger than the membrane thickness, are stabilized by membrane undulations. In the case of the concentrated lamellar phases, attractive van der Waals and repulsive steric forces are the stabilizing mechanisms. It was shown that the disconnection only takes place if the distance between two bilayers is similar to the thickness of the bilayers and it was argued that the disconnection is tuneable by the rigidity of the monolayer. In this combined small angle neutron scattering and NSE experiment we discuss the influence of the structure factor on the dynamics. By applying the theoretical approach of Zilman and Granek we determine the bending elasticity constants in the respected systems.

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Wednesday 5 Sept: Poster presented 17.00-18.00 PLate:1

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PLate:2 Wednesday 5 Sept: Poster presented 18.00-19.00

Effect of electrolyte and temperature on the adsorption properties of quaternary derivatives of lysosomotropic substances Monika Rojewska ; Krystyna Prochaska Poznan University of Technology, Poznan, Poland

Quaternary derivatives of lysosomotropic substances (QDLS) are compounds exhibiting both surface properties as well as special biological activity. QDLS diffuse into the cellular lysosomal compartment where the low pH causes them to become protonated and trapped. As a consequence membrane’s permeability is changed what leads to release of hydrolytic enzymes and the destruction of the living cell. These action of QDLS could supporting cytostatic or antifungal drugs. In view of the biological application of QDLS and their mixtures is necessary to carry out research at the cellular environmental conditions. Living organisms constitute a rich environment in various electrolytes. In turn, the presence of electrolyte strongly influences on the surface properties of QDLS and their biological activity. Therefore, the aim of study was to analyse the adsorption properties of QDLS and their mixtures in air/electrolyte systems. As electrolytes were used 4 different sodium salts. This choice allows to determine the effect of anion of electrolyte on adsorption properties of investigated substances. The measurements were performed for two temperatures: 298K and 309.6 K. QDLS used in our investigations were obtained by quaternization of the appropriate tertiary amines with methyl bromide in diethyl ether. Equilibrium surface tension at the air/electrolyte solution of QDLS was measured by du Noüy ring method. Surface tensions isotherms were approximated by Frumkin’s equation and reorientation model. Based on the dynamic surface tension curves the values of micelle dissociation rate constant were estimated. Moreover, size of micelle was measured by dynamic light scattering method (Zetasizer Nano, Malvern Instrument). Contact angle of considered solution of QDLS was investigated on several surfaces of different hydrophobicity. The obtained results indicate, that addition of salt and temperature rise led to improved surface activity and accelerated the process of adsorption of QDLS at the air/electrolyte interface. However, the observed enhancement of adsorption properties is affected by the type of added anion as well as its concentration.

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Electrochemistry at the oil-water interface in microemulsion Christoffer Johans Aalto University, Department of Chemistry, Espoo, Finland

Electrochemistry at the oil/water interface has been actively studied since the late 1960’s. These systems are since also ions can carry the charge across the interface. Oil/water electrochemistry has been very fruitful for understanding charge equilibriums and ion transfer reactions at soft interfaces. The electrochemical approach is less obvious for dispersed systems, since the microstructure limits electrode arrangement and the huge surface area requires substantial amounts of charge to polarize the interface. Due to these problems electrochemical studies of oil/water interfaces in microemulsion are virtually non-existent. Here, it is shown electrochemical potentials across oil-water interfaces in microemulsion can be followed by choosing one electrode that is selective for the oil phase and one electrode that is selective for the aqueous phase, e.g. decamethylferrocene/decamethylferrocenium at a Pt wire for the oil phase and a saturated calomel electrode for the aqueous phase. The electrochemical potential of any species is constant throughout the system under equilibrium conditions, and thus it is irrelevant where in the system an electrode is placed. Furthermore, the potential across the oil/water interface can be changed by using potential determining salts, which consist of a hydrophilic ion and a hydrophobic ion. These salts polarize the interface by oppositely charging the oil and aqueous phases. In microemulsion, the electroneutrality condition applies only to the system as a whole - the water and oil domains can be charged. The polarization and charge can be calculated using a Debye-Hückel type approach with partition coefficients (transfer potentials) for each ion in the system. The Gibbs-Guggenheim principle states that electric potential between two points of different composition cannot be strictly measured, and must be considered in this context.

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A demonstration of enhancements in interfacial rheological characterisations Stefania Baldursdottir 1; Peter Hodder 2 1Faculty of Health and Medical Sciences, Dept. of Pharmacy, Copenhagen, Denmark; 2TA Instruments, Applications, Elstree, United Kingdom

It has been a number of years since the rotational rheometer have really become sensitive enough to provide a suitable platform to help characterise an interface, whether liquid / air or liquid /liquid. It has been a path to discovery all and many iterations of designs of the actual measuring system (the component actually in the interface) has taken place culminating in the Double Wall Ring (DWR) a joint patented device between two great pioneers of interfacial rheology Jan Vermant and Gerry Fuller in the collaboration with TA Instruments. Such technology has become the basis of many projects and publications associated with the field of interfacial rheology. After previous experimentation by Dr. Stefania Baldursdottir, there was a keen interest in the ability to reduce the concentrations of proteins used for interfacial characterisations so that expensive therapeutically active proteins can be studied as well as the typically used model proteins as bovine serum albumin (BSA) and lysozyme. Previously there was a need for high enough concentrations to produce a signal strong enough to be measured, a limitation of the technology to date. With the introduction of the new Discovery Hybrid Rheometer such limitations were lessened and this poster presents data that shows that it is now possible to define a “control” base interface rheologically, and so provide the investigator with the potential to characterise the effect of additives at varying concentrations. This potential extends into studying concentration below which a monolayer is formed and beyond, and so shows the benefits of enhanced sensitivity which has given rise to the potential to measure an even greater spectrum of interfaces and a means to determine the development of any interface with time or concentration. In this study we have compared the performance of two models of the new Discovery Hybrid Rheometer and the AR G2 rheometer when studying the interfacial adsorption of lysozyme (from hen egg white, Sigma-Aldrich, Denmark) using the double wall ring geometry. The results show great improvement in the detection limit of the protein and the sensitivity of the new rheometers.

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Impact of oxidized phospholipids on the structural and dynamic organization of phospholipid membranes Marcus Wallgren 1; Lenka Beranova 2; Quoc Dat Pham 3; Linh Khanh 1; Martin Lidman 1; Jan Procek 4; Konrad Cyprych 4; Paavo K.J.Kinnunen 5; Martin Hof 4; Gerhard Gröbner 1 1Umeå University, Department of Chemistry, Umeå, Sweden; 2J. Heyrovsky Institute of Physical Chemistry, Prague, Czech Republic; 3Lund University, Physical Chemistry 1, Lund, Sweden; 4Wroclaw University of Technology, Institute of Biomedical Engineering and Instrumentation, Wrocław, Poland; 5Aalto University, Helsinki Biophysics and Biomembrane Group, Department of Biomedical Engineering and Computational Science, Espoo, Finland

Under conditions of oxidative stress, oxidized phospholipids (OxPls) can be formed with profound differences in structural and molecular features from their parent molecules. Once integrated into the membrane, they can dramatically change the membrane's properties and structures that can affect lipid–protein interactions and thereby alter the functions of membrane protein. These changes can have severe consequences which range from the development of several chronic diseases, trigger of immune responses, inflammation, amyloid formation to apoptosis. We applied a combination of macroscopic calorimetric studies with atomic resolution solid state nuclear magnetic resonance (NMR) methods to obtain a direct molecular insight into the impact of OxPls on the organization of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) based biological model membranes. Incorporation of defined OxPls with either a carboxyl group (1-Palmitoyl-2-azelaoyl-sn-glycero-3-phosphocholine (PazePC)) or aldehyde (1-Palmitoyl-2-(9’-oxononanoyl)-sn-glycero-3-phosphocholine (PoxnoPC)) at their truncated sn-2-chain ends enabled us to reveal OxPl species dependent differences. The calorimetric studies showed drastic changes in the phase behavior of lipid membranes upon the presence of OxPls. Temperature dependent changes in the solid state 31P NMR spectra which provided information of the lipid headgroup region in these mixed membrane systems, reflected this complex phase behavior. In the temperature region between 293 K (onset of Lα-phase) and 298 K two overlapping NMR spectra were visible which reflect the co-existence of two liquid-crystalline lamellar phases as visible in the deconvoluted DSC profiles. The observed phase transitions were moved to higher temperatures in the presence of heavy water due to its condensing effect, where additional wideline 2H NMR studies revealed a complex hydration pattern in the presence of OxPls.

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Competing ordering processes at liquid crystal surfaces laden with semifluorinated alkane molecules Xunda Feng 1; Ahmed Mourran 2; Martin Moeller 2; Christian Bahr 1 1Max Planck Institute for Dynamics and Self-Organization, Goettingen, Germany; 2DWI an der RWTH Aachen e.V. and Institute for Technical and Macromolecular Chemistry, Aachen, Germany

We report for the first the tuning of the surface ordering and anchoring behavior at the isotropic liquid crystal/air interface by the adsorption of semifluorinated alkanes. Ellipsometric measurements elucidate the interplay between the surface order at the and a structural phase transition in a Gibbs film on the same interface. Gibbs films formed by the semifluorinated alkane C18H37-C12F25 exhibit a sharp transition from a dilute state at higher temperatures to a dense state at lower temperatures. The transition temperature can be tuned by controlling the C18H37-C12F25 concentration in the bulk liquid crystal phase. When the transition takes place in the temperature range in which a molecular thin smectic or nematic film exists at the isotropic liquid crystal/air interface, the smectic surface order is destroyed while the nematic surface order is affected by a change of the orientation of the liquid crystal molecules. Polarized light microscopy characterization indicates that both behaviors result from a change of the anchoring condition of the liquid crystal molecules in contact with the Gibbs film.

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Aggregation and dispersion of nanoparticles in physiological solutions Anna Godymchuk 1; Evgenia Arzamastseva 1; Elena Yunda 1; Svetlana Milyaeva 2; Denis Kuznetsov 2 1Tomsk polytechnic university, Div. of Nanomaterials and Nanotechnologies, Tomsk, Russian Federation; 2National Research Technological University "MISIS", Inter-chair of teaching and research laboratory "Nanomaterials", Moscow, Russian Federation

The increasing dispersion of engineered nanoparticles into our environment has become a major cause for concern from the viewpoint of environmental and occupational health. Although, thermodynamic instability and high surface energy make nanoparticles lose mobility due to the aggregate in environmental medium; aggregation is considered to be a main problem to prepare stable dispersions of nanoparticles in toxicological testing of nanoparticles. This study was focused on the preparation of stable nanoparticles dispersions on the base of nontoxic physiological liquids. Metal nanopowders of Cu (24.66 m2/g, particles size 27 nm) and zinc (13.58 m2/g, particles size 62 nm), produced with the electrical explosion of wires, and nanostructured powders of Al2O3 (54.75 m2/g) and ZrO2 (8.10 m2/g), obtained with plasma-chemical method, have been used in the work. To make nanoparticles dispersions, phosphate buffering saline, aqueous solution of glucose and synthetic alveolar fluid were used. Aggregation stability of nanoparticles was demonstrated to depend on the powders composition (disperse phase) as well as biological matrix composition (dispersion phase). Experiments included the help of laser diffraction method, electro-acoustic measuring, and transmission electron microscopy. It was figured out that in dispersions, based on nanopowders and physiological media, double dispersions had been formed: unstable suspensions with dispersoid size ~ 10-5-10-4 m, and lyosol’s being stable to aggregation during more than 60 hours (particles size ~ 10-7-10-6). Obtained results can be competitively used to prepare stable nanoparticles dispersions to help toxicologists to deliver nanoparticles to target-organs in their experiments.

412


Colloidal mobility of nanoparticulate extracellular polymeric substance (EPS)coated iron oxides Sneha Narvekar ; Kai Uwe Totsche Friedrich Schiller University of Jena, Chair of Hydrogeology, Institute of Geosciences, Jena, Germany

Solubility and transport of nutrients and pollutants is affected by the presence of colloidal and (organo) mineral compounds which may act as mobile geosorbents. In soils and aquifers, pure and organically modified Fe and Mn oxy-hydroxides are of particular importance as they are progressively used for environmental cleanup. Yet, colloidal stability, reactivity and thus the mobility of such colloids is governed by processes like flocculation/dispersion, filtration and straining, accumulation at the air-water interface, and sorptive interactions with the immobile solid surfaces. The dynamic interactions of the colloidal particles, organic coatings and the components of the natural environments can affect colloidal properties like size, surface charge and hence influence the colloidal stability. In natural systems like soils, sediments and aquifers, Extracellular polymeric substances (EPS) are an important component of the soil organic matter pool. EPS are a complex mixture of biopolymers consisting primarily of polysaccharides and proteins, with variable amounts of lipids and nucleic acids. EPS and its components may form organomineral associates with soil borne iron oxide via adsorption and co-precipitate. Components of EPS are neutral moieties which can ionize as a function of pH, which can affect the colloidal properties of the iron oxides in the soil. These can also change the size and geometry of the particles and bring about a new arrangement of surface sites. The objective of our study is to fundamentally understand how the interactions with EPS affects the surface and colloidal properties of mobile natural geosorbents and their their reactivity and mobility.

413


DNA gels: a new approach for the co-transport of pDNA and drugs Diana Costa 1; Artur Valente 2; Maria Graça Miguel 2; João Queiroz 1 1CICS - Centro de Investigação em Ciências da Saúde, Universidade da Beira Interior, Covilhã, Portugal; 2Department of Chemistry, University of Coimbra, Coimbra, Portugal

In this communication we report the dual release of plasmid DNA (pDNA) and solutes with pharmaceutical interest from pDNA gels cross-linked with ethylene glycol diglycidyl ether. The disruption of pDNA gels over time, after the irradiation of the gel with ultraviolet light (400 nm), was characterized through the cumulative pDNA release, the evolution in dry weight, the extent of swelling and also by the variations in the gel mesh size. The controlled release of different molecular weight solutes (lysozyme, bovine serum albumin (BSA) and fluoresceinisothiocyanato-dextran (FITC-dextran)) from plasmid DNA gels was investigated and the influence of both, the hydrogel degradation and cross-linker density on the release kinetics were addressed. While the release of lysozyme follows a Fickian process, the release of BSA and FITC-dextran is characteristic of a Super Case II release phenomena. In addition, the size of the three solutes partially influences the release behaviour; polymer chains mobility and the degree of swelling also play a role. To gain a fundamental understanding of drug release profile from pDNA matrices, in vitro release studies were evaluated using several anti-inflammatory drugs. The quantification of the release mechanism indicates a Super Case II release profile, which can be related with the gel swelling degree. A correlation between the drug release trend and the drug hydrophobicity can be found, with more hydrophobic drugs showing a slower release rate. In brief, this new pDNA gel system is biocompatible, degradable upon light irradiation and allows for the controlled and sustained release of pDNA and incorporated solutes. This co-delivery of pDNA and drugs would find relevant clinical uses due to the possibility of gene and non-gene therapy combination in order to improve the therapeutic efficiency.

414


Brush-like layers of adsorbed bottle-brush polyelectrolyte: effect of backbone architecture Erik Wernersson ; Per Linse Lund University, Department of Chemistry, Lund, Sweden

Polymer brushes are useful for keeping surfaces separated on the microscopic scale, which is conducive for, e.g., colloidal stability and lubrication. Here, we investigate the structure of brush-like layers, formed by adsorption of hierarchical polyelectrolytes, by molecular simulation of a coarse-grained model. This work is motivated by extensive experimental studies on a novel class of synthetic macromolecules by the group of P. Claesson, KTH, Stockholm. The hierarchical polymers consist of a methacrylate backbone grafted with polyethylene oxide chains and cationic quaternary alkylamine groups in varying proportions, forming a bottle-brush polymer structure with positive charges close to the backbone chain. A simplistic bead-spring model for good-solvent conditions is used, with harmonic springs and Lennard-Jones beads that carry a positive charge where appropriate. The structure of the layer formed by adsorption on a negatively charged surface is found to be sensitive to the density and distribution of charged segments along the backbone chain; a block structure, where cationic groups are concentrated on one side of the backbone, gives rise to a “brush of brushes” structure where the bottle-brush backbones extend perpendicular to the surface, anchored to the surface by the polyelectrolyte block. By contrast, an even distribution of charged sites along the length of the backbone gives rise to an adsorbed layer of a less well-defined structure. The effect of added salt is also considered, and it is found that the structure of adsorbed polymer with the 'block-copolymer' architecture is less strongly affected than for evenly distributed backbone charges, for which extensive desorption is observed.

415


Dissolution of dispersed phase in alveolar suspensions of zinc nanoparticles Elena Yunda ; Anna Godymchuk Tomsk polytechnic university, Div. of Nanomaterials and Nanotechnologies, Tomsk, Russian Federation

Inhaled from the ambient air nanoparticles may reach innermost areas of respiratory tract, alveolar sacs, particularly. In this work the dissolution of electroexplosive zinc nanoparticles (62 nm) in the synthetic alveolar solution has been studied. On the basis of zinc nanopowder and synthetic alveolar solution we prepared suspensions (0.1 wt.%.) being kept for 5…300 minutes with limited access of air. The suspensions then were separated by centrifugation (3000 rot/min) followed by filtration. Afterwards the solutions were conserved with 5% nitric acid solution. The evidence of the total solubility (99 %) of metal nanopowders in the synthetic alveolar fluid has been demonstrated with the help of the stripping voltammetry. Alongside, the mechanism of zinc nanoparticles dissolution related to the electroexplosive zinc nanoparticles completely dissolving in the synthetic alveolar fluid has been proposed. The dissolution was suggested to include the following stages. The first stage comprises the formation of amphoteric zinc hydroxide in the oxygenated suspension of zinc nanoparticles and the synthetic alveolar fluid. The second stage includes the dissolution of zinc hydroxide with the formation of soluble zinc salts. At the third stage the formation of citrate and tartrate complexes of Zn2+ ions has been proposed.

416


Functionalization of titanium surfaces: towards new biofouling resistant materials Vitaly V. Komnatnyy 1; Anna V. Svensson 2; Anne Kathrine K. Overgaard 3; Martin B. Sørensen 2; Graham Broder 4; Peter L. Roach 4; Tim Tolker-Nielsen 5; Michael Givskov 5; Thomas E. Nielsen 1 1Technical University of Denmark, Department of Chemistry, Kgs. Lyngby, Denmark; 2Danish Technological Institute, Center for Plastics Technology, Taastrup, Denmark; 3Coloplast A/S, Humlebæk, Denmark; 4University of Southampton, School of Chemistry, Southampton, United Kingdom; 5University of Copenhagen, Department of International Health, Immunology and Microbiology, Copenhagen, Denmark

Titanium covered with its native oxide layer is a well-known implant material used in pacemaker casings, orthopedic devices and dental applications. A common problem associated with implants is the development of device-related infections which are difficult to treat with antibiotics and cause necrosis of the surrounding tissue, ultimately leading to failure of the medical device. Bacterial biofilm often cover the surface of malfunctioning implants causing specific diseases and the spreading of antibiotic resistance. The development of materials with resistance to biofouling is therefore of highest priority in the medical device industry. In the present work we describe a new approach towards new biofouling resistant materials by the organo-functionalization of titanium, using controlled solid-phase synthesis techniques. Initial acidic and oxidative treatments of the metal surface generate reactive hydroxyl moieties which are subsequently modified with synthetically versatile amine-containing reagents. The resulting material shows high compatibility with standard solid-phase peptide synthesis protocols. Polymer grafting provides amino handles for solid phase chemical synthesis. These initial results are promising for the utility of surface-functionalized titanium for new biofouling resistant material solutions.

417


Study of interaction of human plasma proteins with polymeric nanoparticles as drug carriers with surface plasmon resonance Jaroslav Katrlík 1; Peter Gemeiner 1; Georgi Yordanov 2 1Institute of Chemistry, Slovak Academy of Sciences, Department of Glycobiology, Bratislava, Slovakia; 2Faculty of Chemistry and Pharmacy, Sofia University “St. Kliment Ohridski”, Sofia, Bulgaria

Nanoparticles have a huge potential for use in medicine and biology because their ability of specific and controlled interaction with targeted cells in organisms. The interactions of nanoparticles with individual components of the body can be in general both wanted and unwanted with very serious consequences thus the study of these interactions is of great importance. The blood plasma proteins bind the surfaces of nanoparticles-based colloidal drug carriers immediately upon their entry into an organism. The kinetics of this process is important factor playing a key role in affecting of biodistribution of the drug carriers. For the evaluation of such interactions we have used both drug-free and drug-loaded colloidal nanospheres of poly(butyl cyanoacrylate) as the model system of a colloidal drug carrier. Colloidal drug-free and drug-loaded nanospheres were prepared by emulsion polymerization without and with epirubicin, respectively. The nanospheres were then purified and redispersed in aqueous solutions of surfactant Tween-80. The prepared dispersions were used for study of the interaction with plasma proteins (albumin, fibrinogen, immunoglobulin G) by surface plasmon resonance (SPR) technique using SPR equipment Reichert SR7000DC. The proteins were immobilized on the surface of polycarboxylate hydrogel SPR biochip with medium charge density and the interactions with drug-free and drug-loaded colloidal nanoparticles in physiological phosphate buffer were measured. After detailed evaluation of the results could be obtained quantitative data about studied interactions what is important step to estimate the action of nanoparticles in the body. Acknowledgement: This contribution is the result of the project implementation: Centre for materials, layers and systems for applications and chemical processes under extreme conditions – Stage II supported by the Research & Development Operational Programme funded by the ERDF. This work was supported by CMST COST Action CM1101. G.Y. is thankful to the Bulgarian National Science Fund (project DMU 03-111/2011) for the financial support.

418


419


Importance of charge regulation on the antimicrobial activity

; M. Skepö ; M. Lund Department of Theoretical Chemistry, Lund University, Sweden

Histatins are poly-cationic, salivary peptides which possess antimicrobial activity against oral bacteria and fungi. Unlike the other salivary peptides, histatins are rich in histidines which are proposed in literature as possible reasons of their antimicrobial activity. Since histidine’s pKa value is close to neutral pH, high content of histidine provides histatins an appreciable ability of charge regulation. We are interested in how this charge regulation affects interaction of histatin 5 with charged surfaces. Since microbial membranes are negatively charged, interactions with negatively charge surfaces are of special interest. Here we present Monte Carlo simulations and statistical mechanical modeling of interactions between histatin 5 and charged surfaces as a function of pH where we allow changes in protonation states of titratable groups. We show that histidine residues maximize the charge capacity of histatin 5 around neutral pH. Histatin 5 obtains more positive charges via protonation of histidines in the vicinity of negatively charged surfaces resulting in higher surface affinity. These results support that the charge regulation of histidine residues is a possible mechanism to bind histatins to microbial membranes and to explain their antimicrobial activity. This work was supported by the Linnaeus Center Organizing Molecular Matter and the eSSENCE program at Lund University. Computational resources were provided by LUNARC.

420


Towards nanoengineered templates for improved sers based detection

Bat-El Pinchasik, Admir Masic, Peter Fratzl, Helmuth Mӧhwald and Andre Skirtach. Max Planck Institute for Colloids and Interfaces, Potsdam, Germany.

Microparticles and microcapsules serve as essential building blocks for drug delivery, sensoring and detection in the field of advanced and bio-materials science. In recent years Surface Enhanced Raman Spectroscopy (SERS) attracted attention of the community due to the potential to improve Raman signals several orders of magnitude, down to single molecule detection. Yet, stable and reproducible SERS signals remain a challenge, mostly because of specific morphologies of nanostructures able to induce enhancement. New configurations of chemically modified microcapsules have the potential to improve the stability of the SERS signal.

421

LIST OF POSTERS

List of Posters

P1:1 Cathrine Albèr; Spatial imaging and evaluation of humectants impact on stratum corneum hydration with confocal Raman microscpectroscopy

P1:2 Tehrani-Bagha Ali Reza; Cationic ester-containing gemini surfactants: adsorption at tailor-made surfaces monitored by SPR and QCM

P1:3 Taisuke Banno; Coupling of self-propelled motion and division of oil droplets driven by acetal formation

P1:4 Delfi Bastos-González; Self-assembled PNIPAM nanoparticles: specific ion effects

P1:5 Solmaz Bayati; Temperature-response of γ-cyclodextrin-PNIPAAM diblock copolymer inclusion complexes at the solid/liquid interface

P1:6 Eva Blomberg; Surface-protein interactions on stainless steel – effects of protein adsorption, surface changes and metal release

P1:8 Richard Campbell; Understanding the origin of viscoelasticity in cyclodextrin/surfactant films at the air/water interface

P1:9 Marité Cárdenas; Resolving complexity of the IC2 autoantibody recognized target on the surface of functional β-cells by QCM affinity measurements

P1:10 Xiaoyan Liu; Diblock copolymers with a linear cationic block and a non-ionic bottle-brush block: Adsorption, surface and friction forces

P1:12 Julius de Folter; Interfacial assembly of colloids with a cubic shape

P1:13 Min Wang; The role of association structures in aqueous lubrication

P1:14 Thomas Delclos; Putting a "separation tag" on trivalent lanthanide ions using neutral lipid monolayers and bilayers

P1:15 Marie Delcroix; Mixed PEO/PAA brushes for the control of protein adsorption

P1:16 Katarzyna Dopierala; Polyhedral oligomeric silsesquioxanes (POSS) in mixed Langmuir monolayers

P1:17 Anna Eriksson; Physicochemical characterization of the phosphopeptide/titanium dioxide interaction

P1:18 Andreas Fery; Mechanoresponsive surfaces studied by soft colloidal probe AFM

425

List of Posters

P1:19 Anatoly Filippov; Investigation of opening process of the pores inside hydriphobic membrane under nanofiltration of aqueous-organic mixtures

P1:20 Bartlomiej Gawel; The mutual influence of brine and crude oil composition on interfacial properties of crude oil/brine systems

P1:21 Konstantin Golemanov; Surface shear rheology of triterpenoid and steroid saponins on the air / water interface

P1:22 Carin Hagsten; Removal of protein and mineral based deposit after heat treatment of milk

P1:23 Nicklas Hjalmarsson; Controlling the van der Waals force: a CP-AFM study

P1:24 Virginie Hugouvieux; Self-assembly of amphiphilic block copolymers in solution and close to a surface: a simulation approach

P1:25 Tommi Huhtamäki; Remarks on measuring the contact angle of high contact angle, high hysteresis surfaces

P1:26 Yosuke Imai; Study on the counterion distribution of surfactant adsorbed films by total-reflection XAFS measurement

P1:27 Lucio Isa; Vertical positioning and internal structure of microgel particles at liquid-liquid interfaces

P1:28 Dominic Kehren; Composite microgel-based fibers and films

P1:29 Jacob Judas Kain Kirkensgaard; Complex self-assembly morphologies of multicomponent miktoarm star copolymers

P1:30 Bohinc Klemen; Bacterial adhesion to glass surface. Influence of surface roughness

P1:31 Natalia Kochurova; Adsorption-desorption fenomena on surface of aqueous solutions

P1:32 Juuso T. Korhonen; Local reversible switching between superhydrophobic states on a post array

P1:33 Karina Kovalchuk; Molecular dynamic study of tetra-naphtenic acids at water/oil interfaces

P1:34 Volodymyr Kuznetsov; Study of ion adsorption on modified electrodes by direct force measurements

426

List of Posters

P1:35 Peter Lamberg; Performance of enzymatic biofuel cell in cell cultures

P1:36 Sandrine Le Tirilly; Fragrance Encapsulation: Specific interactions control at the oil-water interface

P1:38 Huihui Li; Chain length effects on the miscibility and distribution of the counterions at the surface of ionic liquids aqueous solution

P1:39 Daniela Meroni; Surface free energy of bare and fluorinated siloxanes: comparing experimental evaluation and dipole moments calculations

P1:40 Daniela Meroni; Roughness influence on the attachment modes of siloxanes on TiO2 surfaces

P1:41 Samir Mezdour; Effect of surface properties on bubble size of a foam produced in a rotor-stator mixer

P1:42 Elena Mileva; Hydrodynamic boundary layers on rising bubbles as a tool for granulometric separation of fine solids

P1:43 Tahereh Mokhtari; Effect of humidity on PEI-CTAB film formation at the air-water interface

P1:44 Adrienne Nelson; Studying complex nanoparticle self-assembly at liquid interfaces using pendant drop tensiometry and microrheology

P1:45 Viet Nguyen-Kim; Solubilization in aqueous media: mechanism and optimization

P1:46 Yoshimune Nonomura; How do we recognize water and oil through our tactile sense?

P1:47 Shogo Oshima; Time-resolved measurement of interfacial tension gradient around a self propelled oil droplet using quasi-elastic laser scattering method

P1:48 Periklis Papadopoulos; Electrokinetics on superhydrophobic surfaces

P1:49 Karthik Reddy Peddireddy; Spontaneous emulsification and dissolution processes of thermotropic liquid crystal compounds in aqueous surfactant solutions

P1:50 Jilska Perera; Competitive adsorption at the n-heptane-water interface

P1:51 Nikolay Puretskiy; Synthesis and properties of robust raspberry-like particles

427

List of Posters

P1:52 Elena Reshetova; Enantioselective adsorption of profen enantiomers on a chiral adsorbent with grafted eremomycin antibiotic

P1:53 Lorand Romanszki; Langmuir films of N-alkanoyl amino acids

P1:54 Juan M. Ruso; Silicon nanowires: fabrication and biofilm formation

P1:55 Jayati Sarkar; Formation of miniaturized patterns at soft interfaces

P1:56 Laurie Saulnier; How does a soap film burst during generation?

P1:57 Stevia Sutanto; Cleanability of textile materials in liquid CO2

P1:58 Olof Svensson; Antibody-antigen interaction on polystyrene: an in situ ellipsometric study

P1:59 Hiroki Takumi; Effect of hydrogen bonding between 1-hexyl-3-methylimidazolium and tetrafluoroborate on miscibility in the mixed adsorbed film

P1:60 Ryo Tanaka; Time-resolved measurement of surface tension of chemical wave in BZ reaction

P1:61 Yuhei Tokiwa; A thermodynamic study on the condensed film formation of cationic surfactant at oil / water interface

P1:62 Eric Tyrode; Preferential adsorption of ions to hydrophobic and polar surfaces studied by vibrational sum frequency spectroscopy

P1:63 Deborah Wakeham; Probing the protic ionic liquid surface using x-ray reflectivity

P1:64 Stefan Wellert; Wetting of solid surfaces by bicontinuous microemulsions

P1:65 Mark Vis; Donnan potentials at the interface between aqueous dextran and gelatin solutions

P1:66 Mary Wood; Revealing metal-liquid interfaces using a wealth of surface-specific techniques

P1:67 Nadja Wulff; Photochemical synthesis of amphiphiles in microemulsions

P1:71 Hamad Allohedan; Using of new modified poly(propylene oxide)/poly(ethylene glycol) block and graft copolymers as demulsifier for petroleum crude

428

List of Posters

P1:72 Nihal Aydogan; Self-assembled nanotubes by the anthraquinone containing-stimuli responsive molecule: effect of pH and redox state

P1:73 Nihal Aydogan; Comparison of the surface behavior of novel ion pair surfactant with natural lung surfactant in the presence of fibrinogen

P1:74 Justas Barauskas; Lipase action on self-assembled lipid liquid crystalline nanoparticles

P1:75 Romain Bordes; Physical chemical study of amino acid-based surfactants

P1:76 Clotilde Bouaoud; Nano-liposomes for the encapsulation of food preservatives

P1:77 Wuge H. Briscoe; Fundamentals of nanotoxicity: Effect of nanoparticles on lowering the energetic barrier of membrane fusion

P1:78 Tinatin Butkhuzi; Infrared study of structural changes of water encapsulated in AOT reverse micelles

P1:79 Celen Cagri Cenker; Towards understanding peptide self-assembly: a model system study

P1:80 Doroty Codoni; The development of lipid-based liquid crystal nanoparticles for protein/peptide drug delivery

P1:81 Jean-Francois Dufreche; Modeling of the topology of semi- rigid bicontinuos microemulsions : frustreated and un-frustrated structures

P1:82 Felix Ertel; Structure of gel-like surfactant solutions

P1:83 Olena Fomina; Quantum chemical analysis of incorporation of alkanes in the fatty alcohol monolayers at the water/vapor of alkanes interface

P1:84 Jonas Fuchs; Distribution of organic additives in micellar solution of surfactants

P1:85 Luigi Gentile; Interaction between Dioctadecyldimethylammonium Bromide (DODAB) Vesicles and Pluronic F127 polymer network

P1:86 Soumen Ghosh; Physicochemical investigation on the bulk and surface properties of the binary mixtures of sodium N-dodecanoyl sarcosinate, SDDS and N-decanoyl -N-methylglucamine, MEGA 10 in aqueous medium

429

List of Posters

P1:87 Juan J. Giner-Casares; Polyoxometalate surfactants as unique molecules for interfacial self assembly

P1:88 Gesche Graf; pH- and salt-dependent aggregation behavior of symmetric single-chain bolaphospholipids

P1:89 Marta Gubitosi; Characterization of carbon nanotube dispersions in solutions of bile salts and their derivatives

P1:90 Manuela Hod; Tailored self-assembly structures of magnetic nanoparticles by tuning interparticle interactions

P1:91 Ibrahim Kayali; Formulation of bicontinuous and water- in - diesel microemulsions using nonionic surfactants and hydrophilic alcohol ethoxylates as co- surfactant

P1:92 Kaushik Kundu; Physicochemical investigation of mixed reverse micellar systems in biocompatible oils: II. Microstructure by conductance and DLS

P1:93 JongChoo Lim; Synthesis of an amineoxide zwitterionic surfactant and characterization of its dual function of detergency and softness

P1:94 Anni Maattanen; Printed gold nanoparticle-based electrodes on paper

P1:95 Yasuharu Nakagawa; Requirement of charged lipids for the hexadecanol-induced gelation in the phospholipid bilayer system

P1:96 Hiromichi Nakahara; Change in secondary structure of model peptide in pulmonary surfactant systems at the air-water interface

P1:97 Hiromichi Nakahara; Langmuir monolayer properties of a series of partially fluorinated alcohols

P1:98 Takayuki Narita; Fabrication of silver nanosheet by reduction on gas-liquid interface

P1:99 Samuli Ollila; Combining molecular dynamics simulations (MD) and solid state nuclear magnetic resonance (NMR) methods for amphiphilic systems

P1:100 Gerardo Palazzo; Tuning microstructure of non-ionic micellar networks: rheology and self-diffusion investigations

P1:101 Claudia Pigliacelli; Characterisation of polymer-bile salts aggregation and its impact on poorly water soluble drugs solubilisation in the gut

430

List of Posters

P1:102 Ana Maria Percebom; EO-grafted polyanions with a cationic surfactant to prepare water-soluble complex salts or stabilized inorganic nanoparticles

P1:103 Irina Portnaya; Mixed micellization between kappa- and beta-caseins

P1:104 Krystyna Prochaska; Physicochemical and functional properties of surfactants and their mixtures used in wetting agents in fire fighting

P1:105 Carlotta Pucci; Albumin binding onto synthetic vesicles

P1:107 Ferran Roig; Hyaluronan based hydrogels as drug delivery system for catanionic sugar-derived surfactants

P1:108 Edvaldo Sabadini; Rheology of wormlike micelle formed by CTAB and different aromatic co-solutes

P1:109 Kazutami Sakamoto; Spontaneous internalization of protein transduction domain into giant unilamellar vesicle by membrane curvature modulation

P1:110 Rüdiger Scheu; Probing oil-surfactant interaction in oil-in-water emulsions using Sum-Frequency-Scattering-Spectroscopy

P1:111 Natalia Selivanova; Lanthanide containing lyotropic liquid crystal based on surfactants: complexation, structure and phase behavior

P1:112 Suraj Sharma; The effect of fluorocarbon/hydrocarbon miscibility on microstructure, phase behavior, and emulsification of Tween 80/oil/water systems

P1:113 Osamu Shibata; Langmuir monolayer behavior of partially fluorinated alcohols (F8HmOH) and dipalmitoylphosphatidylcholine (DPPC)

P1:114 Yutaka Takahashi; Photoinduced viscosity change in mixtures of an anionic photoresponsive amphiphilic compound and a cationic surfactant solution

P1:115 Ali Reza Tehrani-Bagha; Solubilization of two organic dyes by cationic ester-containing gemini surfactants

P1:116 Ali Reza Tehrani-Bagha; Growth of gold nanoparticles using cationic gemini surfactants: effects of structure variations in head and tail groups

P1:117 Leana Travaglini; Between peptides and bile acids: extremely narrow nanotubes by self-assembly of amino acid-substituted cholic acid

431

List of Posters

P1:118 Alexey Victorov; Bending rigidity of a diblock copolymer monolayer containing weak polyelectrolyte subchains and pH-induced shape transitions of copolymer's aggregates in solution

P1:119 Kazimiera A. Wilk; Aggregation of nonionic N-oxide surfactants; experimental and computational approaches

P1:120 Letícia Vitorazi; Structural characterization of systems formed by different cationic surfactants and anionic-neutral block copolymers

P1:121 Doris Vollmer; Phase behavior of microemulsions with weak and strong surfactants

P1:122 Tatsuya Yaguchi; Fluctuation measurement of free-standing bilayer lipid membranes by laser-induced surface deformation spectroscopy

P2:1 Simon Aben; Investigation of the stability of depletion-flocculated emulsions using creep measurements and diffusive wave spectroscopy (DWS)

P2:2 Manja Behrens; Crystalline nanoparticle dispersions do not ripen

P2:3 Philip Born; Agglomeration in sterically stabilized nanoparticle suspensions revisited

P2:4 Stefanie Burger; Influence of the polymer size on depletion attraction-induced gel and glass transitions of microgel colloids

P2:5 Alexander V. Butenko; Dense colloidal fluids form denser sediments

P2:6 Ronja F. Capellmann; Colloidal gels under shear

P2:8 Vivianne Deniz; Effect of non-electrostatic physisorption on charge-regulated surface forces

P2:9 Karla Doermbach; Silica-coated hematite nanoparticles using water-soluble polyalkoxysiloxanes

P2:10 Aude Vernhet; Protein conformation and aggregation in white wines: effect of physico-chemical parameters

P2:11 Ben Erné; DHS equations of state from slow analytical centrifugation in ultrathin capillaries

P2:12 Florian Evers; Particle dynamics in one- and two-dimensional random potentials

432

List of Posters

P2:13 Mathias Fleury; Colloidal Stability of emulsions and nanoparticles in pharmaceutics

P2:14 Jan Forsman; Many-body interactions in colloidal dispersions

P2:15 Andrea Fortini; Fluid mediated gelation and crystallization of hard spheres

P2:16 Luigi Gentile; Physical chemistry analysis of bitumen as a colloidal system

P2:17 Nicoletta Gnan; Critical Casimir forces in colloidal suspensions: a numerical study

P2:18 Konstantin Golemanov; Effect of cationic polymers on the foam rheological properties

P2:19 Anna Große; Sensitive polymer-clay composite particles: stability and adsorption mechanism

P2:20 Yannick Hallez; Effect of particle anisotropy or polydispersity on the equation of state of colloidal dispersions

P2:21 Mathias Hanisch; Colloid titration of silica particles – Determination of specific interactions by a surface-sensitive method

P2:22 Peter Holmqvist; Concentration dependent swelling of loosely cross-linked ionic microgel dispersions in the fluid regime

P2:23 Manuel Häuser; pH-triggered polyelectrolyte desorption from electrostatically surface modified poly(lactic-co-glycolic acid) nanoparticles

P2:24 Baptiste Jaquet; Stabilization of polymer colloid dispersions with pH-sensitive poly(acrylic acid) brushes

P2:25 Malgorzata Jaworska; Characterization of gel formulations used for paint stripping

P2:26 Marek Kosmulski; Enhanced electrolytic dissociation in low-dielectric-constant systems

P2:27 Marco Lattuada; Breakup dynamics of colloidal clusters in shear flows

P2:28 Jérôme G.J.L. Lebouille; Self-consistent field predictions for quenched spherical biocompatible triblock copolymer micelles

433

List of Posters

P2:29 J.G.J.L. Lebouille; Controlled nanoparticle formation by diffusion limited coalescence

P2:30 Chang-Soo Lee; Synthesis of Janus particles using micromolding technique

P2:31 Per Linse; Adsorption versus aggregation. Particles and surface of same material

P2:32 Shlomo Magdassi; Coalescence of Metallic Nanoparticles at Room Temperature and Application in Printed Electronics

P2:33 Paul Menut; Acid coagulation of natural rubber latex

P2:34 Adriana M. Mihut; Interactions and self-assembly of soft magneto-responsive anisotropic colloids

P2:35 Jules Mikhael; Fractionation of Complex Industrial Colloidal Systems

P2:36 Priti Mohanty; Dipolar ionic microgels

P2:37 Gemma Montalvo; Colloidal metallic nanoparticles as surface-enhanced raman Spectroscopy substrates for forensic analysis of questioned documents

P2:38 Maria Morga; Streaming potential studies of hematite nanoparticle monolayers on mica

P2:39 Solenn Moro; Open colloidal structures by hydrophobization of silica aqueous suspensions

P2:41 Magdalena Oæwieja; Controlled desorption of silver nanoparticles from the heterogeneous surfaces

P2:42 Marc Obiols-Rabasa; Depletion interaction in mixed thermoresponsive microgel systems

P2:43 Victoria Proskurina; Flocculation of TiO2 by hybrid polymer-inorganic nanosystems

P2:44 Kareem Rahn-Chique; Theoretical-experimental evaluation of the flocculation rate of nanoemulsions from turbidity measurements

P2:45 Kevin Roger; Nano-emulsifications through surfactant hydration : the PIT and PIC methods revisited

P2:46 Kevin Roger; Why are hydrophobic/water interfaces negatively charged?

434

List of Posters

P2:47 Akira Satoh; On the viscosity-modifying method for generating the Brownian motion of dispersed particles in a magnetic suspension

P2:48 Jeroen van Duijneveldt; Controlling the behaviour of aqueous montmorillonite suspensions through surfactant adsorption

P2:49 Jenny Algotsson; Monte Carlo simulations of Donnan equilibrium in cartilage

P2:50 Mohd. Sajid Ali; Ascorbic acid induced α-helix to β-sheet transition of bovine serum albumin

P2:51 Paulino Alonso-Cristobal; Detection of heavy metal ions using water soluble conjugated polymer

P2:52 Luís Alves; Ionization by pH and anionic surfactant binding gives the same thickening effects of crosslinked polyacrylic acid derivatives

P2:53 Dan-Florin Anghel; Assessing the properties of a DTAF-labeled hydrophilic-hydrophobic copolymer in water and surfactant micelles

P2:54 Ayman Atta; Facile preparation of stabilized core- shell magnetite acrylamide-co-acrylic acid nanoparticles

P2:55 Alejandro Barrantes; Biocompatibility of poly-L-lysine/heparin multilayers

P2:56 Artem Bezrukov; Association of Cationic Polyelectrolytes with Sodium Alkylsulphates in Aquoeus-Organic Solutions

P2:57 Romain Bordes; Polyelectrolyte gels: effect of material homogeneity on swelling

P2:58 Leonardo Chiappisi; Mixtures of chitosan and oppositely charged alkyl ethoxy carboxylates:How surfactant micelles affect the structure of polyelecte

P2:59 Yoo Seong Choi; Coacervated recombinant mussel adhesive proteins as a model system of complex coacervates for biomedical applications

P2:60 Lucie Grebikova; Study of mechanical properties of dendronized polymers at single molecule level

P2:61 Charlotte Gustavsson; Deposition of structured polymer-surfactant particles onto different substrates – a study using time-resolved ellipsometry

435

List of Posters

P2:62 Per Hansson; Segregation and mixing of proteins in polyelectrolyte gels

P2:63 Chrisitiane A. Helm; Temperature-induced transition from odd–even to even–odd effect in polyelectrolyte multilayers

P2:64 João Henriques; Theoretical studies of intrinsically disordered proteins in solution and adsorbed to surfaces

P2:65 Sheng-Shu Hou; The influence of tetraalkylammonium bromides on the complexation behavior between poly(N-vinyl pyrrolidone) and sodium dodecyl sulfate

P2:66 Benson K. Money; Role of polymer-nanofiller interaction for polymer electrolyte dynamics

P2:67 Katarzyna Kilan; Multilayer polymer films as functional membranes and coatings for nanocapsules in application for molecular biomedicine

P2:68 Konstantinos Kyriakos; Cononsolvency in aqueous solutions of P(S-b-NIPAM) diblock copolymers

P2:70 Flavia Laffleur; Slippery surface nanoparticles for enhanced mucus penetration

P2:71 Marco Laurenti; Searching for the mechanism of fluorescence quenching by cytochrome c in conjugated polymers

P2:72 Olga Mednova; Long-term modification of a polymer microfluidic device for easy chromosome spreading

P2:74 Alesya Mikhailovskaya; Impact of denaturants on the dynamic surface properties of globular protein solution

P2:75 Reinhard Miller; Stabilization of emulsion by polyelectrolyte/surfactant mixtures

P2:76 Sebastian Orban; Investigation of the pH dependent Poly(acrylacid)/Porphyrin complex formation

P2:77 Jacek Patkowski; Influence of magnetic field on adsorption of PEI on hematite

P2:78 Torbjorn Pettersson; Sacrificial bonds between surfaces coated with PEC and PEM containing nanoparticles

P2:79 Alois Popp; Xanthan gelation

436

List of Posters

P2:80 Mark Pothecary; Challenges in the measurement of protein zeta potential

P2:81 Roland Ramsch; Hydrogel analysis by microrheology in the drug delivery field

P2:82 Cesar Rios; Stretchable silicone-supported hydrogel for mechanotransduction systems

P2:83 J. Ray Runyon; Asymmetric flow-field flow fractionation of cationic nanomaterials using surface modified regenerated cellulose ultrafiltration membranes

P2:84 Hideo Sawada; Amphiphilic fluoroalkyl end-capped N-(1,1-dimethyl-3-oxobutyl)acrylamide – acryloylmorpholine cooligomer possessing solvatochromic and thermochromic behaviors

P2:85 Yulia Sergeeva; Multilayered films for studying cell adhesion in chemically well-defined conditions

P2:86 Borislav Soklev; Thermoresponsive vesicles obtained by self-assembly of PNIPAM-g-PEO double hydrophilic graft copolymer for delivery of indomethacin

P2:87 Adriana Sturcova; Associative processes in thermoresponsive polymers: charge formation and the effect of additives

P2:88 Krzysztof Szczepanowicz; Polyelectrolyte nanocapsules with emulsion core

P2:89 Krzysztof Szczepanowicz; Protein – furcellarane complexes for nanocapsule formation

P2:90 Franco Tardani; Protein-based gels as carbon nanotubes dispersants

P2:91 Ulrika Lundgren; Studying Structural Changes of Polymer Films in Real-Time using QCM-D

P2:92 John Erik Wong; Ultrafiltration membranes modified using the LbL technique for enhanced performances

P2:94 Justas Barauskas; Hydration behavior, functions and medical applications of soy phosphatidyl choline and diglyceride lipid compositions

P2:96 Jonas Carlstedt; Role of hydration on the physicochemical properties of native, acid hydrolyzed, and cross-linked starch

437

List of Posters

P2:97 Gesche Graf; Hydration of biofilms studied with a high-resolution QCM-D scanning technique

P2:98 Sanna Gustavsson; Understanding salt dissolution in the almost dry regime

P2:99 Marija Jankunec; The phase behavior of dioleoylphosphatidylcholine in water

P2:100 Elena Mileva; Interactions of lipopolysaccharides and antennary glycine compounds in aqueous media

P2:101 Farida Shagieva; Manifestation of ion specificity in the behaviour of dynamic dielectric permittivity of aqueous solutions of alkali halides

P2:102 Yana Znamenskaya; Hydration of pig gastric mucin studied by AFM, two calorimetric techniques and QCM-D

P2:103 Mickael Antoni; Numerical simulations of the hydrodynamics of a water droplet in paraffin oil

P2:104 Victoria Dutschk; Wetting behaviour of water on hydrophobized chemically and mechanically roughened glass and silica surfaces with defined morphologies

P2:105 Michele Ferrari; Amphiphilic molecules and disperse systems at superhydrophobic surfaces

P2:106 Anna Jarzycka; Surface quasi-two-dimensional electrolyte model applied to describe the electrolyte influence upon surface activity of dicephalic pH-responsive sugar surfactants

P2:107 Tania Lind; Antimicrobial dendrimers show different association mechanisms for lipid membranes with different physical properties

P2:108 Reinhard Miller; CFD Simulations of dynamic profiles for growing drops

P2:109 Francesca Ravera; The role of the interfacial properties in the particle stabilized foams and solid foams

P2:110 Victor Starov; Evaporation of sessile droplets of water–based surfactant solutions: experiments and computer simulations

P2:111 Anna Trybala; Kinetics of spreading of nanofluids

P2:112 Asmat Ullah; Deformation based on interfacial tension during microfiltration of oil drops on a slotted pore membrane

438

List of Posters

P2:113 Vinay Chauhan; Synthesis, Characterization and Physico-chemical Investigation of New Piperazinium and Pyridinum Cationic Surfactants

P2:114 Alfredo Gonzalez-Perez; Mechanics of Nerves

P2:115 Ana Kroflic; Interactions of parabens with self-associated structures

P2:116 Róbert Mészáros; Nonequilibrium association of oppositely charged linear polyelectrolytes and surfactants in the presence of dodecyl maltoside

P2:117 Veronica L. Morales; Controlled colloid pattern assembly and attachment strength in evaporating droplets

P2:118 Hideaki Oshima; Development of novel drug delivery system by tunable plasma lipoprotein

P2:119 Aiva Plotniece; Studies of nanoaggregates formed by 1,4-dihydropyridine amphiphiles possessing antiradical activity

P2:120 Bojan Sarac; Thermodynamics of micellization of ionic and non-ionic surfactants from DSC measurements

P2:121 Kamil Wojciechowski; Surface activity of saponin from Quillaja bark at the water/air and water/oil interfaces

P2:122 Anan Yaghmur; Self-assembled nanostructures of fully hydrated monoelaidin-elaidic acid and monoelaidin-oleic acid systems

P2:123 Mirjana I. Comor; A combined theoretical and experimental study of Surface Modified Anatase Colloidal Nanoparticles

P2:124 Edit Fegyer; Effect of linear nonionic polymer additives on the association between poly(diallyldimethylammonium chloride) and sodium dodecyl sulfate

P2:125 Murielle Schmitt; Role of water transfer mechanisms in the struture of water in paraffin oil emulsions

P2:126 H. Ibrahim Unal; Quarternized-poly(N-vinylimidazole)/montmorillonite nanocomposite: synthesis, characterization and electrokinetic properties

P2:127 Bastian Wedel; A simple copolymer system to linearly tune size and phase transition properties of non-NIPAM based microgels

439

List of Posters

P2:128 Michael Zeiser; Phase behavior of linearly thermoresponsive core-shell microgels

P2:129 Jie Zhao; Formulation of A Nano-additive Inkjet Ink for Fabric Functionalization

P2:130 Tereza Halasova; Polyelectrolyte-surfactant interaction in Hyaluronan-CTAB system around critical aggregation concentration

P2:131 Jaroslav Katona; Shear-induced structure formation in a mixture of hydroxypropylmethyl cellulose and sodium dodecyl sulfate

P2:132 Jitka Krouská; Tensiometric study of surfactant micellization induced by hyaluronan

P2:133 Miloslav Pekaø; Binding of hyaluronan to CTAB micelles - a turbidimetric study

P2:134 Arunas Ramanavicius; Enzymatic synthesis of conducting polymers

P2:136 Ozlem Erol; Colloidal behaviors of poly(3,4-ethylenedioxythiophene)/TiO2 nanotube hybrid nanoparticles

P2:137 Jordi Esquena; Synthesis and characterization of meso/macroporous TiO2-P2O5 and TiO2-P2O5-SiO2 materials, using highly concentrated emulsions as templates

P2:138 Davide Gardini; Silica-coating as protective shell for the risk management of nanoparticles

P2:139 Gospodinka Gicheva; Purification of water from nanosized pollutants

P2:140 Vilcinskas Karolis; Self-assembly of polymer-graphene oxide barrier films

P2:141 Margarlta Sanchez-Dominguez; CeO2, CuO and CuxCe(1-x)Oy NPs prepared in O/W microemulsions

P2:142 Anna Bratek-Skicki; Electrokinetic studies of protein adsorption on latex particles

P2:143 Eduardo Guzman; Impact of nanoparticles on the interfacial properties and structure of lipid monolayers

P2:144 Davor Kovacevic; Complexation of lysozyme with sodium poly(styrenesulfonate)

440

List of Posters

P2:145 Polina Prokopovich; Controlling bacterial adhesion via surface micro/nano-patterning

P2:146 Almira Ramanaviciene; Evaluation of immobilization technique influence on the efficiency of immunosensors

P2:147 Xiantao Shen; Multi-functional micro-containers constructed from molecularly imprinted nanoparticles

P2:148 Anan Yaghmur; In-situ formation of lipidic bupivacaine-loaded formulations: SAXS characterization and in vitro drug release properties

P2:149 Kell Mortensen; Nano-Composite Gel composed of Micellar Network and Silica Nano-Particles. A combined SAXS and SANS Study.

P3:1 Antoine Bailly; Morphogenesis from deformation of biomimetic microcapsules

P3:2 Urszula Bazylinska; Polymeric nanocapsules and nanospheres for photodynamic therapy use; optimization and stability

P3:5 Desire' Di Silvio; Study of the biophysical interactions between core-shell nanocarriers and liquid-supported model of cell membranes

P3:6 Jana Dulle; Sonochemical formation/activation of metal alloy based heterogeneous catalysts

P3:7 Alexandre Emelyanenko; The interaction of superhydrophobic and hydrophobic coatings on magnesium surface with aqueous solutions

P3:8 Stefanie Eriksson; Isotropic diffusion weighting in microscopically anisotropic systems with PGSE NMR using a magic-angle sweep of the q-vector

P3:9 Mustafa Ersoz; Immobilization and characterization of human serum albumin onto polyelectrolyte coated ITO surface

P3:10 Betul Ertekin; Synthesis of silver-deposited silanized magnetite nanoparticles and their biosensor application

P3:11 Magnus Falk; Membrane- and mediator-less miniature nanostructured biofuel cells for ex vivo and in vivo applications

P3:12 Emiliano Fratini; Cement: a two thousand year old nano-colloid

P3:13 Jerome Fresnais; Polymer / nanoparticle interactions: From hydrohobic to hydrophilic materials

441

List of Posters

P3:14 Rodorico Giorgi; Inhibition of iron-gall ink corrosion and deacidification of historically valuable manuscripts by using earth-alkaline Hydroxide

P3:15 Hanna Gustafsson; QCM-D as a method for monitoring enzyme immobilization in mesoporous silica particles

P3:16 Lu Han; Structural study of mesoporous crystals with bicontinuous structures

P3:17 Mathias Hanisch; Facile synthesis of silver nanoparticle necklaces on sub-micron silica spheres

P3:18 Imren Hatay Patir; The self assembled monoloyers (SAMs) of silanes on ITO electrodes and their electrochemical behaviour

P3:19 Fritz Huguenin; Lithium ion electro-insertion in self-assembled films from TiO2, chitosan, and silver nanoparticles

P3:20 Malgorzata Jaworska; The effect of cosurfactants on the physicochemical properties of Crodamol PC-based nanoemulsions

P3:21 Helka Juvonen; Modification of surface properties of latex coatings for enhanced print quality of silver nanoparticle ink

P3:22 Andreas Keilbach; Studying the microwave-assisted synthesis of CdSe quantum dots by small-angle X-ray scattering

P3:23 Tomas Kjellman; Transient colloidal stability controls the particle size of mesoporous silica SBA-15

P3:24 Daniel Kluge; Probing nanomechanical structure-property relationships of micro- and nanofibers by AFM bending experiments

P3:25 Marta Kolasinska-Sojka; Influence of ionic strength and pH on electroactive properties of the multilayer films containing conductive nanoparticles

P3:26 Vida Krikstolaityte; Investigation of viscoelastic properties of assembled gold nanoparticle mono- and multilayer structures using QCM-D

P3:27 Niall Maclean; The shape evolution of cobalt ferrite in a one-pot synthesis

P3:28 Laurent Maillaud; Improvement of nanotube based conductive inks via depletion interactions

442

List of Posters

P3:30 Daisuke Nagao; Synthesis of asymmetric composite dumbbells and their directed orientation in electric field induced assembly

P3:31 Kazuya Nakajima; Preparation of low-molecular organic crystals with gold luster and expression mechanism of gold luster

P3:32 Thomas Neicke; Quantitative characterization of biomaterials and their interaction with living cells by atomic force microscopy

P3:33 Silke Nemeth; Zinc modified by ultrasound for photocatalytic wastewater treatment

P3:34 Cécile Noirjean; Solidified microemulsions

P3:35 M.R. Noor El-Din; Investigating factors affecting water-in-diesel fuel nanoemulsions

P3:36 Keita Okuno; Preparation and thermal tability of novel fluoroalkyl end-capped styrene dimer/silica nanocomposites

P3:37 Mustafa Ozmen; Synthesis of magnetic core-shell Fe3O4-Ag nanoparticles for biomolecule immobilization

P3:38 Andreea Pasc; Solid lipid nanoparticles as novel template for porous silica and hybrid anticancer drug loaded materials

P3:39 Andrij Pich; Multifunctional nanogels as building blocks for nanostructured materials

P3:40 Francesca Ridi; Effect of chemical admixtures on the hydration kinetics of cementitious materials

P3:41 Francesca Ridi; Hydration reaction of Portland cement in the presence of carbonate and a superplasticizer: influence of the temperature

P3:42 J. Ray Runyon; Tackling complex nanomaterial with field-flow fractionation

P3:43 Seiichi Sakamoto; Construction and expression of fluobody against Amphiphilic Saponin, Ginsenosides for Fluorescence-Linked Immunosorbent Assay

P3:44 Karin Schillen; Internally structured nanoparticles of surfactant ion-polyion complex salt and nonionic surfactant

P3:45 Saki Souma; Preparation and thermal stability of fluorinated sulfonic acid derivatives/silica nanocomposites

443

List of Posters

P3:46 Taiki Tsuzuki-ishi; Controlling photochromism between fluoroalkyl end-capped oligomer/polyaniline and /N,N’-diphenyl-1,4-phenylenediamine nanocomposites induced by UV-light-responsive titanium oxide nanoparticles

P3:47 Kazimiera A. Wilk; CdSe quantum dots encapsulated in polymeric micelles

P3:48 Patrick Wuennemann; Modification of wrinkled surfaces through defects and their application for nanostructures of soft matter particles

P3:49 Hiroshi Yao; Ion-based organic dye nanoparticles with versatile fluorescence colour tunability: efficient antenna effect

P3:50 Salih Yildiz; Interaction of donepezil and human serum albumin on amine-modified magnetic nanoparticles

P3:51 Damien Bazin; Controlled deposit of polymer nanoparticles onto a conductive solid substrate and its functionalization by a protein

P3:52 Sebastian Bjorklund; Molecular mobility of the skin barrier by polarization transfer solid-state NMR

P3:53 Alexander Böker; Ultrathin membranes from polymer-protein conjugates: from self-assembly to membrane performance

P3:55 Chia-Chen Chang; Aptamer-based colorimetric detection of platelet-derived growth factor using unmodified gold nanoparticles

P3:56 Anton Fagerström; Effects of adjuvants on tebuconazole leaf cuticle penetration

P3:57 Marie Grey; Membrane interaction of α-synuclein in different aggregation states

P3:58 Argyro Kalaitzaki; Formulation and structural characterization of o/w nanoemulsions as effective carriers of bioactive compounds

P3:59 Ishara Kamalanathan; Characterisation of biosurfactants for industrial applications

P3:60 Sebastian Kapp; Protein adsorption to hydrophobic nanospheres

P3:61 Liselott Lindh; Saliva adsorption onto different materials studied by QCM-D

P3:62 Antonia Mallardi; Immobilization of biomolecules for biosensing application

444

List of Posters

P3:63 Sania Maurer; Behaviour of oil bodies under processing conditions

P3:64 Silvia Milani; Modelling the kinetics of Nanoparticles interacting with plasma proteins

P3:65 Jadranka Milanovic; Surface and viscous properties of gelatin/Na caseinate mixtures

P3:66 Maura Monduzzi; Interfacial properties of proteins: Hofmeister effects on surface charge of BSA

P3:67 Costanza Montis; Smart lipid assemblies for DNA complexation: structure at the nanoscale and interaction with membrane models

P3:68 Fereshteh Naderi; Interaction between fullerene and vitamins

P3:69 Yushi Oishi; Pressure dependence on penetration behavior of Vibrio cholerae Hemolysin into lipid monolayers on PBS subphase

P3:70 Gerardo Palazzo; Interfacial effects in bio-molecules integrated into organic field effect transistors

P3:71 Liliya Petrova; Effects of calcium and bicarbonate on phase distribution of the reaction products and cholesterol as studied in in-vitro model

P3:72 Ilya Reviakine; The role of surface ion binding in TiO2-platlet interactions.

P3:73 Marina Juliane Richter; Template-directed synthesis of mineral hollow capsules and investigations on dynamics of protein adsorption

P3:74 Seiichi Sakamoto; Interaction of Glycyrrhizin with Lipid Rafts Model by Langmuir Monolayer Study

P3:75 Ulrike S. Schmidt; Pectins from different plant sources and their effect on emulsion stability

P3:76 Veronique Schmitt; Reverse emulsions stabilized by water-dispersible microgels: anti-Bancroft Pickering emulsions

P3:77 Mireia Subinya Albrich; Structure and Dynamics of Candida Antactica B in Microemulsions

P3:78 Peter H. Thiesen; Characterization of human dental enamel by imaging spectroscopic ellipsometry

445

List of Posters

P3:80 Pauline Vandoolaeghe; Challenges around colloid and interface science when formulating agrochemical active ingredients

P3:81 Huihui Wang; Bioinspired synthesis of silica capsules

P3:82 Zahari Vinarov; In-vitro study of the effect of surfactants on triglyceride lipolysis under conditions mimicking the human digestive tract

P3:83 Aristotelis Xenakis; Reverse micellar nanosystems for enzymic biocatalysis: structure-activity relationship

P3:84 Marianna Yanez Arteta; Interactions of PAMAM dendrimers with designer biosurfactants

P3:85 Jarzycka Anna; New sunscreen emulsions containing polyphenolic extracts; stability and in vitro photoprotective activity and photostability efficacy

P3:86 Dominik Burger; Synthesis and polymerization kinetics of sterically stabilized perfluorinated aqueous latex

P3:87 Julius de Folter; Generic, thermo-reversible assembly of colloids in microtubes

P3:88 Shigeru Deguchi; Nanoemulsification process inspired by extreme environment in deep-sea

P3:89 Reinaldo Digigow; Functional silica coated superparamagnetic iron oxide nanoparticles (SPIONs) – preparative aspects and characterization

P3:90 David French; Production of monodisperse Pickering emulsions

P3:91 Rodorico Giorgi; Semi-interpenetrating p(HEMA)/PVP hydrogels for the cleaning of water-sensitive canvas paintings

P3:92 Gemma Gutierrez; Preparation of HIPEs with controlled droplet size containing lutein

P3:93 Gaelle Bealle; Surface decoration of catanionic vesicles by magnetic iron oxide nanoparticles for on-demand delivery in mild hyperthermia

P3:94 Michael Klossek; Completely water dilutable green microemulsions

P3:95 Michael Klossek; Formulation of homogeneous, nano-structured mosquito repellent solutions with p-menthane-3,8-diol (PMD) as active in presence of ethanol and sesame oil

446

List of Posters

P3:96 Charlotte Knittel; DNA mediated complex formation of cationically modified triglyceride nanocrystals for gene delivery

P3:97 Maria Matos; Preparation of water-in-oil-in-water (W1/O/W2) double emulsions containing Resveratrol

P3:98 Helene Monteillet; Ionic liquid-in-water emulsions for separation purposes

P3:99 Maria del Carmen Moran; Nuclear proteins on the formation of DNA gel particles as controlled DNA delivery systems

P3:100 Monica Mosca; Liposomes as carriers of anti-inflammatory compounds for ophthalmic applications

P3:101 Maxime Nollet; Encapsulation of B12 vitamin in concentrated double emulsion

P3:102 Luigi Paduano; Ruthenium-based complex nanocarriers for cancer therapy

P3:103 Veronique Schmitt; Thermo-breakable capsules

P3:104 Terhemen Andrew Tyowua; Fluorosilica particles at air-oil surfaces

P3:105 Roberta Angelini; Relaxation dynamics in an ageing glassy colloidal suspension

P3:106 Beate-Annette Brüning; Influence of charge density on bilayer bending rigidity in lipid vesicles: a combined dynamic light scattering and neutron spin-echo study

P3:107 Beate-Annette Brüning; Fluctuation dynamics in unilamellar phospholipid vesicles: Influence of temperature, cholesterol and trehalose

P3:108 Luigi Gentile; Viscosity oscillations in a lamellar phase system

P3:109 Christina Graf; Improved magnetic properties of iron oxide nanoparticles for magnetic resonance imaging by post-synthesis oxidation and surface-modification

P3:111 Matthias Karg; Gold nanocrystal superlattices: a small angle neutron scattering study

P3:112 Tsang-Lang Lin; X-ray reflectivity and grazing-incident X-ray scattering studies on mixed thiolated-gold nanoparticle/lipid monolayer

447

List of Posters

P3:113 Annabelle Medebach; Soft matter in the subzero degree Celsius regime: studying frozen food with x-ray phase contrast tomography

P3:114 Guillaume Meriguet; Structure and dynamics of large hydrophobic ions in concentrated aqueous solutions

P3:115 Kathryn Miller; Calcite crystallisation in the presence of biopolymers: A neutron reflection study

P3:116 Costanza Montis; Nucleolipid bilayers: a neutron reflectometry and QCM study

P3:117 Thomas Ortmann; Effect of adsorbed polyelectrolytes with different degree of polymerization on lipid monolayers between fluid and solid state

P3:118 Coralie Pasquier; Equation of state and structure of highly concentrated globular protein solutions

P3:119 Asger B. Petersen; Deposition from AAm/MAPTAC SDS formulations on hydrophobised and hydrophilic silica – how composition and deposition are affected by dilution and co-deposants

P3:120 Diego Pontoni; Synchrotron Scattering Techniques for Industrial Applications

P3:121 Martin Schmiele; Modelling phospholipid stabilized dispersions of colloidal crystals by means of small angle x-ray and neutron scattering

P3:122 Gregory Smith; Small-angle neutron scattering (SANS) as a tool to study charging in nonpolar liquids

P3:123 Olaf Soltwedel; NREX Neutron/x-ray contrast reflectometer

P3:124 Tobias Unruh; Dynamical heterogeneities in phospholipid membranes

P3:125 Norman Wagner; Self-assembly of cationic surfactant and block copolymers in protic ionic liquids

P3:126 Rebecca Welbourn; Functional group dependence of lubrication additive behaviour

P3:127 Stefan Wellert; A neutron spin-echo study of membrane dynamics in disconnected lamellar phases

448

List of Posters

PLate:2 Monika Rojewska; Effect of electrolyte and temperature on the adsorption properties of quaternary derivatives of lysosomotropic substances

PLate:3 Christoffer Johans; Electrochemistry at the oil-water interface in microemulsion

PLate:4 Stefania Baldursdottir; A demonstration of enhancements in interfacial rheological characterisations

PLate:6 Quoc Dat Pham; Impact of oxidized phospholipids on the structural and dynamic organization of phospholipid membranes

PLate:7 Xunda Feng; Competing ordering processes at liquid crystal surfaces laden with semifluorinated alkane molecules

PLate:8 Anna Godymchuk; Aggregation and dispersion of nanoparticles in physiological solutions

PLate:9 Sneha Narvekar; Colloidal mobility of nanoparticulate extracellular polymeric substance (EPS)coated iron oxides

PLate:10 Artur Valente; DNA gels: a new approach for the co-transport of pDNA and drugs

PLate:11 Erik Wernersson; Brush-like layers of adsorbed bottle-brush polyelectrolyte: effect of backbone architecture

PLate:12 Elena Yunda; Dissolution of dispersed phase in alveolar suspensions of zinc nanoparticles

PLate:13 Anna V. Svensson; Functionalization of titanium surfaces: towards new biofouling resistant materials

PLate:14 Jaroslav Katrlík; Study of interaction of human plasma proteins with polymeric nanoparticles as drug carriers with surface plasmon resonance

PLate:16 ; Importance of charge regulation on the antimicrobial activity

PLate:17 Bat-El Pinchasik; Towards nanoengineered templates for improved sers based detection

449

AUTHOR INDEX

Author index (* = presenting author)

Aastrup, Teodor P1:9 Abariute, Laura P3:26 Abdulin, Nail P1:31 Abe, Masahiko P1:109 Aben, Simon P2:1* Aberg, Christoffer O6:2* Abraham, Alexandra O4:4 Ábrahám, Ágnes O1:7 Aburai, Kenichi P1:109 Adamczyk, Zbigniew OC:19,

P2:142, P2:38, P2:41

Adel, Ruud den P2:79 Adelsberger, Joseph P2:68 Agmo Hernandez, Victor P1:17 Agog, H OC:1 Agogo, Hezekiah P2:110 Agrawal, Garima P2:9 Ahrens, Heiko P3:117 Aidarova, Saule P2:75 Åkesson, Anna OC:18,

P1:9 Åkesson, Torbjörn P2:49 Albèr, Cathrine P1:1* Alexander, Cameron P2:135 Alfredsson, Viveka P3:23 Algotsson, Jenny P2:49* Ali, Mohd. Sajid P2:50* Ali Reza, Tehrani-Bagha P1:2* Alla, Synytska O3:8* Allohedan, Hamad P1:71*,

P2:54 Al-Lohedan, Hamad P2:50 Almdal, Kristoffer P2:72 Alonso Cristóbal, Paulino KNC:2,

P2:51* Alvarez, Rubén O1:18 Alvarez Asencio, Rubén P1:23 Alves, Luís P2:52* Ambrosone, Luigi P3:100 Amin, Samiul P1:100 An, Junxue P1:13 Anachkov, Svetoslav OC:10* Ananthapadmanabhan, Kavssery

P2:18, OC:10

Andoralov, Viktor P3:11 Andre, Xavier OC:26 Andreeva, Daria V. P3:33,

P3:6 Andrew, Piers P1:32 Angela M., Falchi O8:1 Angelico, Ruggero P1:100 Angelini, Roberta P3:105* Angelov, Borislav O2:9 Anghel, Dan-Florin P2:53* Angione, Maria D. P3:70 Angus-Smyth, Anna O9:6

Ankerfors, Caroline P2:78 Anna, Jarzycka P3:85* Annaka, Masahiko P2:149 Annunziata, Rita P1:40 Antoni, Mickael P2:103*,

P2:125 Antunes, Filipe E. P2:52 Arabadzhieva, Dimi O4:13 Arashi, Yuichiro P1:46 Aratono, Makoto O1:14,

P1:26, P1:38, P1:59, P1:61

Ardizzone, Silvia O6:8, P1:39, P1:40

Arleth, Lise P1:81 Arndt, Karl-Friedrich P2:19 Arnebrant, Thomas O7:5,

P1:35, P1:58, P2:102, P2:55, P3:11, P3:26, P3:61

Ashiba, Koji P3:49 Atanasov, Yasen P3:82 Atkin, Rob O1:18,

P1:63 Atta, Ayman P2:54* Aura, Susanna O6:14* Avni, Sharon P1:103 Axelos, Monique A. V. P1:24 Aydogan, Nihal P1:72*,

P1:73* Azzam, Eid OC:25* Baran, Adriana P2:53 Backov, Renal P3:103 Baghbanzadeh, Mostafa P3:22 Baglioni, Piero OC:13*,

P3:116, P3:12, P3:14, P3:3, P3:40, P3:41, P3:67, P3:84, P3:91

Bahr, Christian P1:49 Plate:7

Bailly, Antoine P3:1* Balaceanu, Andreea P3:81 Baldelli Bombelli, Francesca P1:101,

P3:5, P3:64

Baldi, Giacomo KNC:1

453


Baldursdottir, Stefania O7:8 Balevicius, Zigmas P2:146 Ballauff, Matthias O3:12 Banc, Amélie O6:12 Banchelli, Martina OC:13 Banerjee, Sulalit P1:20 Baniukevic, Julija OC:24 Banno, Taisuke P1:3* Baoukina, Svetlana O2:6* Barabanov, William P2:56 Barauskas, Justas P1:74*,

P2:94*, P2:99

Barrantes, Alejandro O7:5, P2:55*, P3:26, P3:61

Bartsch, Eckhard P2:4, P3:86

Basheva, Elka OC:10 Basinska, Teresa P2:53 Bastani, Dariush P2:108 Bastos-González, Delfi P1:4* Bauduin, Pierre O2:5 Baulin, Vladimir O7:7 Bawab, Abeer Al PLate:5*,

PLate:1* Bayati, Solmaz P1:5*,

P3:44 Bazin, Damien O3:9,

P3:51* Bazylinska, Urszula P3:2* Bealle, Gaelle P3:93* Beaufils, Sylvie P3:118 Beddoes, Charlotte M. P1:77 Behrens, Manja P2:2* Belayeva, Elena P1:83 Benaglia, Maurizio P1:39 Benyahia, Lazhar O2:8,

O6:6* Beranova, Lenka PLate:6 Bergenholtz, Johan P2:6 Berger, Ruediger O1:1 Berger, Sebastian O3:8,

P3:39 Bergström, Karin P3:56 Bergström, Lennart O9:2*,

P1:23 Bernard, Dominique O4:3 Bernard, Olivier P3:114 Bernkop-Schnürch, Andreas P2:70 Berret, Jean François P1:120 Berti, Debora O6:5,

OC:13, P3:116, P3:67, P3:84

Bertinetti, Luca OC:9*

Bester-Rogac, Marija P2:115, P2:120

Bezrukov, Artem P2:56* Bhowmik, Debsindhu P3:114 Biaggi, Cinzia P1:39 Billsten, Peter P1:1 Binks, Bernard P3:104 Bjorklund, Sebastian P3:52* Blanzat, Muriel P1:107 Blin, Jean Luc P3:38 Block, Stephan P2:63 Blomberg, Eva P1:6* Blosi, Magda P2:138 Blum, Marc-Michael O7:6 Blum, Zoltan P3:11 Blume, Alfred O2:1,

P1:88 Boeglin, Christine P3:109 Boeker, Alexander OC:20,

O6:9, P3:48, P3:73, P3:81

Boinovich, Ludmila P2:101, P3:7

Böker, Alexander O3:13, P3:53*

Bollen, Dirk OC:26 Bone, Stephane P1:36 Bonelli, Nicole P3:91 Bonfils, Frederic P2:33 Bonini, Massimo OC:13,

P3:3* Boom, Remko O3:10 Bordes, Romain P1:75*,

P2:57* Borkovec, Michal O4:10,

P2:60 Born, Philip P2:3* Borzacchiello, Assunta O4:1 Bothe, Dieter P2:108 Bouaoud, Clotilde P1:76* Bouchoux, Antoine P3:118 Boufarguine, Majdi O6:6 Boulmedais, Fouzia P2:82 Bourgeois, Damien P1:14 Boutonnet, Magali OC:12,

P2:141 Bower, Chris P1:32 Boyko, Volodymyr P2:35 Bozeya, Ayat Plate:5 Brandner, Birgit D. P1:1 Bratek-Skicki, Anna OC:19*,

P2:142* Braunova, Alena P2:87 Braz, André P2:37 Bresch, Stefan O1:2

454


Brezesinski, Gerald O2:1, OC:8, P1:87

Briscoe, Wuge O2:12 Briscoe, Wuge H. OC:4*,

P1:77* Broder, Graham Plate:13 Brogren, Carl-Henrik P1:9 Brost, Michèle O1:2 Brückel, Thomas O9:2 Brûlet, Annie P3:3 Brundin, Patrik P3:57 Brüning, Beate-Annette P3:106*,

P3:107* Brusselle, Damien O2:5 Bucak, Seyda P1:79 Bucciarelli, Saskia O7:2* Bulpett, Jennifer O2:12* Bünsow, Johanna P1:18 Burger, Dominik P3:86* Burger, Stefanie P2:4* Burghammer, Manfred P3:120 Busch, Sebastian P3:124 Buschard, Karsten P1:9 Butenko, Alexander V. P2:5* Butkhuzi, Tinatin P1:78* Butt, Hans-Juergen O1:1,

O1:6, O1:15

Buzoglu, Leman P3:50 Bysell, Helena O7:4 Cabane, Bernard P2:39,

P2:45, P2:46, P3:118

Çakmak, M. Ekrem P2:117 Calvimontes, Alfredo P1:57 Calzolari, Davide O9:3 Calzolari, Davide C.E. O9:1 Campbell, Richard O9:6*,

O1:7 Campbell, Richard A. O9:4,

P1:5, P1:8*

Campos-Terán, José P1:8 Cao, Yuanyuan O6:7 Capellmann, Ronja F. P2:6* Cappelletti, Giuseppe P1:39,

P1:40 Carboni, Maura O8:1 Cardenas, Marite OC:18* Cárdenas, Marité P1:9*,

P2:107 Cardona-Castro, Maria-Antonia OC:12 Cardoso, Marcus P2:95* Carlstedt, Jonas P2:96* Carriere, David P3:93 Carrière, David P3:34 Caserta, Sergio PLate:1*

Castro, E. P2:7* Castro, Emilio P3:4* Ceglia, Gaetane O4:3 Ceglie, Andrea O6:4,

P1:100, P3:100

Cekavicus, Brigita P2:119 Cellesi, Francesco P2:135 Cenker, Celen Cagri P1:79* Ceotto, Michele P1:39 Cha, Hyung Joon P2:59 Chaikin, P.M. KN8 Chang, Chia-Chen P3:55* Chang, Debby P1:74 Chauhan, Vinay P2:113* Che, Shunai O6:7*,

P3:16 Chen, Philipp W. O1:4* Chen, Yi-Tang P3:112 Chevalier, Sébastien P3:51 Chiappisi, Leonardo P2:58* Chiara, Sinico O8:1 Chida, Shigeki O1:3 Chirazi, Ali O4:3 Choi, Chang-Hyung P2:30 Choi, Yoo Seong P2:59* Christensen, Jørn B. O8:4 Christoforou, Maria OC:8 Chuliá, Raquel O1:11 Ciani, Laura P1:106 Claesson, Per P1:10 Clarke, Paul P2:80 Clarke, Stuart P1:66,

P3:115, P3:126

Clegg, Paul P3:90, O8:3

Coca, Jose P3:92, P3:97

Codoni, Doroty P1:80* Cogan, Uri P1:103 Cohen Stuart, M.A. P2:28,

P2:29 Collins, Ian P3:126 Colonna, Alfredo P3:102 Comor, Mirjana I. P2:123* Conn, Charlotte O2:2 Coppola, Luigi P1:85 Cordeiro, Y P3:83 Costa, Anna Luisa P2:138 Costa, Diana PLate:10 Costa-Balogh, Fatima O2:10 Costas, Miguel P1:8 Cotrone, Serafina P3:70 Cottet, Hervé O8:4 Cranston, Emily O1:18 Crassous, Jerome O3:1*,

O3:12, P2:34

455


Crawford, Russell O7:7* Cristofolini, Luigi KNC:1* Cugia, Francesca P3:66 Cui, Yannan P2:48 Cuomo, Francesca O6:4* Curtis, Robin P3:59 Cuvelier, Gerard P1:41 Cyprych, Konrad PLate:6 Dabkowska, A.P. O6:1* Dabrowska, Paulina OC:19,

P2:142 Daillant, Jean O9:1 Damyanova, Borislava P3:82 Dane, Thomas G. OC:4 Danino, Dganit OC:11*,

P1:103 D'Annibale, Andrea P1:117 Danov, Krassimir OC:2,

OC:10 Darbha, Gopala Krishna P1:11* Darmanin, Connie O2:2 Davies, John P1:66 Davis, Sean O2:12 Dawson, Kenneth O6:2,

P3:64 de Aguiar, Hilton B. P1:110 de Campo, L PL1 de Campo, Liliana O2:2 De Diego Vindel, Maria Pilar P2:71 de Folter, Julius P1:12*,

P3:87* De Santo, Maria P. P2:16 de Souza, Rodrigo O.M.A. P3:83 Decher, Gero P2:85 Dedinaite, Andra P1:10,

P1:13 Degand, Simon O6:13* Deguchi, Shigeru P3:88* Delclos, Thomas P1:14* Delcroix, Marie P1:15* Delpivo, Camilla P2:138 Deme, Bruno OC:6 Demé, Bruno O1:5 Deng, Xu O1:6,

P1:48 Denier, Claude O8:2 Deniz, Vivianne P2:8* Denkov, Nikolai P1:21,

P2:18, P3:71, P3:82

Derre, Alain P3:28 D'Errico, Gerardino O4:1* D'errico, Gerardino P3:102 D'Espinose de LaCaillerie, Jean-Baptiste

P2:39

Destdribats, Mathieu P3:103 Destribats, Mathieu O1:17*,

P3:76

Deutsch, Moshe O9:1 Di Cola, Emanuela P1:106 di Gregorio, Maria Chiara O2:11* Di Matteo, Nicola P3:100 Di Silvio, Desire' P3:5* Dias, Rita O4:5* Diat, Olivier O2:5,

O1:5, OC:6, P1:14

Diatta, Joseph P2:20 Dietsch, Hervé O3:1,

P2:34, P3:89

Digigow, Reinaldo P3:89* Dijkstra, Marjolein O3:5,

O3:14 Dilli, Gokce P1:73 Dobbrow, Celin P1:90 Dobner, Bodo P1:88 Doermbach, Karla P2:9* Domingues, Joana A.L. P3:91 Dopierala, Katarzyna P1:16* Douzan, Stephan O2:10 Drazic, Goran P1:30 Drescher, Simon P1:88 Drummond, Calum O2:2* Drummond, Carlos P1:4 Duan, Yingying O6:7 Dubois, Cedric P3:113 Ducept, Fabrice P1:41 Duenweg, Burkhard O1:15 Dufreche, Jean-Francois P1:81* Dufrechou, Marie P2:10* Duignan, Timothy OC:7 Dul, Marie-claire P1:14 Dulle, Jana P3:33,

P3:6* Dulle, Martin OC:15 Dupont-Gillain, Christine O6:13,

P1:15 Dutschk, Victoria P1:57,

P2:104* Duvail, Magali P1:81 Dybal, Jiri P2:87 Eastoe, Julian P3:122 Edler, Karen J. KN1*,

P1:43 Edwards, Katarina P1:17 Egel, Laura P3:95 Egelhaaf, Stefan U. O7:3,

O3:3*, P2:12, P2:6

El-Hamouly, Sabrnal P3:35 Elling, Lothar OC:20 Eltes, Felix O9:4 Emelyanenko, Alexandre P3:7* Endress, Hans-Ulrich P3:75

456


Engblom, Johan P1:1, P2:102, P3:56

Engelskirchen, Sandra P3:77 Erath, Johann P1:18 Erb, Randall M O8:2 Erb, Randall M. O1:4 Eriksson, Anna P1:17* Eriksson, Caroline P3:84 Eriksson, Stefanie P3:8* Erné, Ben O3:11*,

P1:65, P2:11*

Erol, Ozlem P2:126, P2:136*

Ersoz, Mustafa P3:10, P3:18, P3:37, P3:9*

Ertekin, Betul P3:10*,

P3:37 Ertel, Felix P1:82* Esquena, Jordi P1:107,

P2:137* Evangelatov, Alexander OC:23 Evans, M E PL1 Evers, Florian O7:3*,

O3:3, P2:12*

Ewa, Skiba P3:2 Fagerström, Anton P3:56* Fainerman, Valentin P1:83 Faizova, Regina P2:43 Falk, Magnus P1:35,

P3:11* Falsini, Sara P1:106 Falus, Peter P3:106,

P3:107 Farago, Bela P3:106 Farras, Pau O2:5 Faul, Charl OC:4 Faure, Chrystel O3:9*,

P3:51 Fayyad, Manyer Plate:5 Fegyer, Edit P2:124* Fegyver, Edit P2:116 Feiler, Adam A. P1:23 Félix, Olivier P2:85 Feng, Xunda Plate:7* Feracci, Hélène P3:51 Ferrari, Michele P2:105*,

P2:109, P2:143

Ferreira, Tiago P1:99 Fery, Andreas P1:18*,

P3:24 Filippelli, Luigi P2:16 Filippov, Anatoly P1:19*

Fischer, Cornelius P1:11 Fischer, Viktor O6:11 Fleury, Mathias O3:4*,

P2:13* Fluerasu, Andrei P3:105 Fomina, Olena P1:83* Forcada, Jacqueline O6:12 Forsman, Jan O4:7*,

P2:14*, P2:49

Fortini, Andrea P2:15*, Fortuño, Joana P3:99 Frackowiak, Renata P3:47 Fragneto, Giovanna P3:116 Franssila, Sami P1:32 Franze, Kristian P1:32 Fratini, Emiliano P3:12*,

P3:40 Fratzl, Peter OC:9 French, David P3:90* Frenkel, Daan KN7 Fresnais, Jerome O6:5*,

P3:13* Freudensprung, Ines P2:128 Früh, Johannes P2:69 Fuchs, Jonas P1:84* Fujinami, Masanori O2:7*,

P1:122, P1:47, P1:60

Fujita, Ichiro P1:97 Fuller, Gerry P1:36 Furlan, Marco O6:10 Futaki, Shiroh P1:109 Fyhr, Peter P2:96 G. Rubio, Ramón O1:11 Galantini, Luciano O2:11,

P1:117, P1:89, P3:44

Galiote, Nelson P3:19 Galyametdinov, Yuriy P2:43 Galyametdinov, Yury P1:111 Gancarz, Roman P3:85 García Ruiz, Carmen P2:37 Garcia-Blanco, Francisco P2:51 García-Celma, MªJosé P1:107 Garcia-Garcia, Alejandro P2:141 Gardini, Davide P2:138* Gavryushov, Sergei O5:2* Gawel, Bartlomiej P1:20* Gawlitza, Kornelia OC:17* Gazeau, Florence P3:93 Gazzoli, Delia P1:89 Geisel, Karen P1:27 Geitenbeek, Robin P1:12 Gemeiner, Peter PLate:14 Genix, Anne-Caroline O6:12

457


Gentile, Luigi P1:85*, P2:16*, P3:108*

German, Natalija OC:24, P2:134

Gernandt, Jonas P2:62 Ghosh, Soumen P1:86* Gicheva, Gospodinka P2:139* Gillich, Torben O9:3,

P1:44 Giner-Casares, Juan J. P1:87* Giorgi, Rodorico P3:14*,

P3:91* Givskov, Michael PLate:3 Giustini, Mauro P3:62 Glasson, Sarah P1:50 Glatter, Otto OC:15 Gnan, Nicoletta P2:17* Godic Torkar, Karmen P1:30 Godymchuk, Anna Plate:8*,

Plate:12 Goerigk, Günther P1:82 Golemanov, Konstantin OC:2,

P1:21*, P2:18*

Gomes, Wellington P3:19 Gonçalves, Karen P3:83 Gong, Xiaojuan O2:2 González Sanchez, Maria Isabel

P2:71

Gonzalez-Perez, Alfredo P2:114* Gorel, Florence P3:91 Gosecka, Monika P2:53 Gosteva, Marina P2:119 Goto, Yuki P3:36 Gottlieb, Moshe P1:90 Gradzielski, Michael O2:9,

P1:45, P2:58

Graf, Christina P3:109* Graf, Gesche P1:88*,

P2:97* Grandner, Stefan PL4 Granmo, Marcus P3:11 Grassia, Paul P3:59 Grebikova, Lucie P2:60* Grey, Marie P3:57* Grillo, Isabelle O6:12,

O4:9, P2:68

Grimes, Brian P1:33 Gröbner, Gerhard PLate:6 Groenewold, Jan O3:14 Große, Anna P2:19* Grouchko, Michael P2:32 Gubitosi, Marta P1:89* Guido, Stefano Plate:1 Gumus, O. Yunus P2:126 Gunning, Patrick P1:101

Günther, Jens-Uwe P3:117 Gupta, Swati P3:72 Gurnon, Kate O9:5 Gustafsson, Emil O1:16 Gustafsson, Hanna P3:15* Gustavsson, Charlotte P2:61* Gustavsson, Sanna P2:98* Gutierrez, Gemma P3:92*,

P3:97 Guzman, Eduardo P2:143* Guzmán, Eduardo P2:105,

P2:109 Gyurova, Anna P2:100 Hagfeldt, Anders P1:17 Hagsten, Carin P1:22* Halasova, Tereza P2:130* Hallez, Yannick P2:20* Hamberg, Lars P1:22 Hamit-Eminovski, Jildiz P3:26 Han, DongSung P1:93 Han, Lu O6:7,

P3:16* Hanes, Richard D. L. O3:3,

P2:12 Hanisch, Mathias P2:21*,

P3:17* Hansson, Per O7:4,

P2:62* Hansson, Petra O1:10 Hariharan, K. P2:66 Harries, Daniel OC:14 Harshe, Yogesh M. P2:27 Harwigsson, Ian O8:4,

P2:99 Hasan, Jafar O7:7 Hassan, Natalia P1:54 Hatay Patir, Imren P3:18*,

P3:37, P3:9

Häuser, Manuel P2:23* Hawley, Adrian O2:2 Hedberg, Jonas P1:6 Hedberg, Yolanda P1:6 Heimburg, Thomas P2:114 Heinen, Marco P2:22 Hellweg, Thomas O7:6*,

P1:64, P2:127, P2:128, P3:107

Helm, Chrisitiane A. P2:63* Helm, Christiane A. O4:8*,

P3:117 Hemar, Yacine P2:33 Hendy, Shaun P1:37 Henriques, João P2:64* Hermann, Raphael, P. O9:2 Herminghaus, Stephan P1:49 Hernández-Pascacio, Jorge P1:8

458


Heux, Laurent P3:1 Hidalgo-Álvarez, R. P2:7 Hijnen, Niek O8:3* Hiltl, Stepanie O3:13 Hiltl, Stephanie O6:9* Hirano, Chikayo P1:113 Hirano, Taka-aki P3:69 Hjalmarsson, Nicklas P1:23* Hochwald, Shir R. P2:5 Hod, Manuela P1:90* Hodder, Peter Plate:4 Hoeppener, Stephanie O6:8 Hof, Martin Plate:6 Holdaway, James A. KN1 Holdich, Richard P2:112 Holmberg, Krister BLS4*,

P1:115, P1:116, P1:2, P1:75, P3:15

Holmqvist, Peter O3:6*, P2:22*

Holtze, Christian P2:1 Hou, Sheng-Shu O4:6*,

P2:65* Hu, Yuan P3:112 Huang, Jianbin P3:87 Huck, Wilhelm T. S. P1:18 Huet, Gilles P1:15 Hugouvieux, Virginie P1:24* Huguenin, Fritz P3:19* Huhtamäki, Tommi P1:25* Hung, Chin-Hua P3:112 Hyde, S T PL1* Ieva, Baleviciute P2:146 Ifuku, Nao P3:88 Ihalainen, Petri P1:94,

P3:21 Iizuka, Mari P3:36,

P3:46 Ikigai, Hajime P3:69 Ikkala, Olli P1:32 Imai, Yosuke P1:26*,

P1:38 Imaz, Ainara O6:12 In, Martini P1:106 Innings, Fredrik P1:22 Ionov, Leonid O1:13,

P1:51 Iovescu, Alina P2:53 Irace, Carlo P3:102 Isa, Lucio O9:3*,

P1:27*, P1:44

Isaksson, Hanna KN9b* Ishii, Haruyuki P3:30 Ito, Thiago P1:108 Ivanov, Evgeni P2:86

Ivanov, Vladimir P1:19 Ivanova, Elena O7:7 Izumi, Shunsuke P2:84 J. Bonales, Laura O1:11 Jaber, Robben KN1 Jachimska, Barbara P2:89 Jain, Titoo P1:116 Jaksch, Sebastian O4:9*,

P2:68 Jamroz, Ewelina P2:89 Janiak, John P1:102,

P3:44 Jankovic, Ivana A. P2:123 Jankunec, Marija P2:94,

P2:99* Jaquet, Baptiste P2:24* Jaroslav, Voroanovic P2:134 Jarzycka, Anna P2:106* Javadi, Aliyar P2:108 Jaworska, Malgorzata P2:25*,

P3:20* Jena, Kailash C. P1:110 Jeng, U-Ser P3:112 Jensen, Henrik P2:148 Jensen, Kathrine Louise P1:9 Jezierski, Adam P1:119 Jiang, Lingxiang P3:87 Jierry, Loic P2:82 Jódar-Reyes, A.B. P2:7 Johannsmeier, Julia O3:2 Johans, Christoffer Plate:3* Johansson, Erik O1:16,

P2:78 Johnson, Eric S. P3:119 Johnsson, Markus P2:99

P2:94 Jokinen, Ville P1:32 Jonas, Ulrich O4:14 Jönsson, Bengt O1:8 Jordan, Rainer O4:9 Jorgensen, Lene O7:8*,

P3:60 Josten, Elisabeth O9:2 Jover, Aida O2:11 Jud, Corinne O7:2 Julija, Baniukevic P2:134 Jung, Laura P2:85 Justina, Kirlyte P2:146 Juvonen, Helka P3:21* K. Money, Benson P2:66* Käck, Camilla P1:9 Kai, Yoshinobu P1:98 Kalaitzaki, Argyro OC:21,

P3:58* Kaldre, Dainis P2:119 Kamalanathan, Ishara P3:59* Kang, Sung-Min P2:30 Kanie, Kiyoshi O6:3*,

P1:97

459


Kapp, Sebastian P3:60* Kappe, C. Oliver P3:22 Karasiewicz, Joanna P1:16 Karbaschi, Mohsen P2:108 Karg, Matthias P3:111*,

P3:127 Karlsson, Ola P2:61 Karolis, Vilcinskas P2:140* Kasavi, Yaron O2:11 Kasimova, Marina P3:60 Kaszuba, Michael P2:80 Kato, Satoru P1:95 Katona, Jaroslav OC:26*,

P2:131* Katrlík, Jaroslav PLate:14

* Kausaite, Asta OC:24,

P2:134 Kausaite-Minkstimiene, Asta P2:146 Kayali, Ibrahim P1:91* Kegel, Willem O3:14,

P1:12, P3:87

Kehren, Dominic P1:28*, P3:39

Keilbach, Andreas P3:22* Keller, Thomas P3:123 Kemp, Roger P3:122 Kennedy, Danielle O2:2 Keyser, Ulrich KN3* Kezwon, Aleksandra P2:121 Khanh, Linh Plate:6 Khaydukov, Yury P3:123 Kibar, Guenes P3:81 Kida, Tetsuya P1:98 Kiesow, Andreas P3:78 Kijima, Tetsushi P3:46 Kikuchi, Mieko P3:45 Kilan, Katarzyna OC:16,

P2:67* Kim, Jong Ah O6:2 Kinane, Christian P3:115 Kinnunen, Paavo K.J. Plate:6 Kirby, Andrew P1:101 Kirby, Nigel O2:2 Kirillova, Alina O3:8 Kirkensgaard, Jacob Judas Kain

P1:29*

Kitahara, Yuichi P1:61 Kitahata, Hiroyuki P1:60 Kjellman, Tomas P3:23* Kjellström, Sven O4:11 Klapp, Sabine PL4 Klemen, Bohinc P1:30* Kleshchanok, Dzina O3:6 Klitzing, Regine v. OC:17 Klosseck, Michael OC:6

Klossek, Michael O1:5*, P3:94*, P3:95*

Klucereva, Marina P2:104 Kluge, Daniel P3:24* Klupp Taylor, Robin N. P2:21,

P3:17 Knittel, Charlotte P3:96* Kochan, Jozef P2:92 Kocherbitov, Vitaly O5:1*,

P2:102, P2:96, P2:97, P2:99, P3:56

Kochurova, Natalia P1:31* Kodama, Shun P3:45 Koehler, Karsten P3:75 Kohlbrecher, Joachim P3:108 Köhler, Ralf O4:8,

P2:69* Kolasinska-Sojka, Marta P3:25* Kolb, Max P1:24 Komnatnyy, Vitaly V. Plate:13 Kondo, Yukishige P1:114,

P3:31, P3:31

Konno, Mikio P3:30 Konovalov, Oleg P3:120 Koos, Erin O3:2* Koper, Ger P2:140 Korhonen, Juuso T. P1:25,

P1:32* Kosmulski, Marek P2:26* Kovacevic, Davor P2:144* Kovalchuk, Karina P1:33* Kovalchuk, Nina O1:2 Koynov, Kaloian O1:15 Krafft, Marie Pierre P1:113 Kraft, Daniela O3:14* Krägel, Jürgen OC:3 Kralchevsky, Peter OC:2*,

OC:10 Krastev, Rumen P2:69 Kraus, Tobias P2:3 Krebs, Thomas O3:10* Kressler, Jörg O2:1 Krikstolaityte, Vida OC:24,

P2:134, P3:26*

Kriz, Jaroslav P2:87 Krodkiewska, Irena O2:2 Kroflic, Ana P2:115* Krouská, Jitka P2:132* Kuliesius, Jurgis OC:24,

P2:134 Kundu, Kaushik P1:92*

460


Kunz, Werner O1:5, OC:6, P3:94, P3:95

Kupka, Julia P3:77 Kuroha, Rie P1:3 Kurtanidze, Manoni P1:78 Kurz, Tomas P3:75 Kuwahara, Haruka P1:109 Kuznetsov, Denis PLate:8 Kuznetsov, Volodymyr P1:34* Kwasny, Dorota P2:72 Kyriakos, Konstantinos O4:9,

P2:68* La Mesa, Camillo P1:105,

P2:90 Laffleur, Flavia P2:70* Lah, Jurij P2:120 Lamberg, Peter P1:35* Lampis, Sandrina O8:1 Landfester, Katharina O6:11 Landsmann, Steve P1:87 Langdon, Blake O7:1* Langer, Klaus P2:23 Langevin, Dominique P1:56 Lapeyre, Veronique P3:76 Larpent, Chantal O3:9,

P3:51 Larsen, Claus P2:148 Larsson, Anette P2:57 Larsson, Iben P3:60 Larsson, Kåre BLS1* Lartigue, Lenaic P3:93 Laschewsky, André P2:68 Lasic, Samo P3:8 Lattuada, Marco O6:10*,

P2:27* Laurati, Marco P2:6 Laurenti, Marco KNC:2,

OC:5, P2:51, P2:71*

Lavalle, Philippe P2:82 Lazzara, Giuseppe P1:5 Le Floch-Fouéré, Cécile P3:118 Le Tirilly, Sandrine P1:36* Leal, Ivana P3:83 Leal-Calderon, Fernando O1:17,

P3:76 Lebouille, J.G.J.L. P2:29* Lebouille, Jérôme G.J.L. P1:76,

P2:28* Lechevalier, Valérie P3:118 Lee, Chang-Soo P2:30* Lee, Chung-Han P3:55 Lee, Ming-Tao P3:112 Lee, Sannamu P1:96 Lee, Seung Yeon P3:115 Lee, Thomas P1:37*

Leech, Ralph OC:22 Leermakers, F.A.M. P3:98 Leermakers, Frans A.M. P2:28 Lekhlifi, Adil P2:103 Lekkerkerker, Henk N. W. O3:6 Leontidis, Epameinondas OC:8*,

P1:14 Lesaint, Caterina P1:20 Leunissen, Mirjam KN7* Lewandowska, Joanna P2:121 Lewinska, Agnieszka P1:119 Li, Huihui P1:26,

P1:38* Lidman, Martin Plate:6 Liggieri, Libero P2:105,

P2:109, P2:143

Liley, Jessica O2:3* Lim, JongChoo P1:93* Lim, Seonghye P2:59 Limage, Stéphanie P2:125 Limbach, Hans Jorg P3:113 Lin, Chii-Wann P3:55 Lin, Jia-Hsien O4:6 Lin, Shi-Yow P2:74 Lin, Tsang-Lang P3:112* Lind, Tania OC:18,

P2:107* Lindfors, Lennart P2:2 Lindh, Liselott O7:5,

P3:61* Lindman, Björn O6:4,

P2:52, P3:99

Linke, H. O6:1 Linnros, Jan O1:10 Linse, Per P2:31*,

Plate:11 Linse, Sara P3:57 Lips, Alex P2:18,

P3:71, P3:82

Liu, Ben O6:7 Liu, Chao P1:13 Liu, Feng O6:3 Liu, Ruixue P2:135 Liu, Shaohua O6:7 Liu, Xiaoyan P1:10* Liyanage, Chathudina J. O8:4 Löbbe, Christian O7:7 Loglio, Giuseppe P2:74 Loh, Watson P1:102,

P1:120 Longtin, Rémi O4:10 Lopez, Francesco O6:4 López Cabarcos, Enrique P2:71 Lopez-Barron, Carlos P3:125

461


Lopez-Cabarcos, Enrique KNC:2, OC:5*, P2:51

López-López, J. M. P2:7 López-López, María P2:37 Lorén, Niklas P1:22 Ludwig, Roland P3:11 Luetzenkirchen, Johannes P1:11 Luigjes, Bob P2:11 Lund, Mikael P2:64 Lundin, Maria P1:6 Lundin, Tom P1:94 Luo, Shuangjiang P2:93 Ly, Isabelle O4:3 Maattanen, Anni P1:94*,

P3:21 Maciejewski, Hieronim P1:16 Mackovic, Mirza P3:17 Maclean, Niall P3:27* Maczka, Edward P2:26 Madsen, Anders KNC:1,

P3:105 Maeno, Takashi P1:46 Maenosono, Shinya P3:27 Magdassi, Shlomo P2:32* Magliulo, Maria P3:70 Maheo, Laurent O4:3 Maillaud, Laurent P3:28* Majumdar, Himadri P1:94 Makaraviciute, Asta P2:146 Makievski, Alexander OC:3 Makuska, Ricardas P1:10 Malikova, Natalie P3:114 Mallardi, Antonia P3:62*,

P3:70 Malmsten, Martin O7:4* Maltas, Esra P3:50 Malte, Paßvogel O4:8 Manca, Maria L. O8:1 Mangiapia, Gaetano O4:1,

P3:102 Mano, João F. P3:4 Månsson, Ronja O7:4 Marais, Andrew O1:16 Marcelja, Stjepan P1:81 Marcus, Julien P3:94 Marguerre, Ann-Kathrin P1:45 Mari, Margherita O6:11 Maroni, Plinio O4:10*,

P2:60 Marschall, Holger P2:108 Martin, Peter P3:59 Martinez Pedrero, Fernando O1:11 Mateescu, Anca O4:14 Matos, Maria P3:92,

P3:97*

Matsubara, Hiroki P1:26, P1:38, P1:59, P1:61

Matsubara, Masaki O6:3 Matsumoto, Akiko P3:31 Matthias, Karg OC:17 Maurer, Sania P3:63* Mayama, Hiroyuki O1:3 Mayes, Andrew P3:5 Mazeiko, Viktor OC:24,

P2:134 McGillivray, Duncan P3:110 McNaughter, Paul P3:5 Medda, Luca P3:66 Medebach, Annabelle P3:113* Mednova, Olga P2:72* Meesters, Gabrie M.H. P1:76 Meijer, Janne-Mieke O3:6 Meijide, Francisco O2:11 Meinders, Marcel O1:9 Meireles, Martine P2:20 Meister, Annette P1:88 Melin, Thomas P2:92 Melzak, Kathryn O4:14* Menager, Christine P3:93 Mendez-Villuendas, Eduardo O2:6 Mendoza, Alma O1:11 Menut, Paul P2:33* Meriguet, Guillaume P3:114* Meroni, Daniela O6:8*,

P1:39*, P1:40*

Messina, Paula V. P1:54 Mészáros, Róbert P2:116*,

P2:124 Mezdour, Samir P1:41* Mezzenga, Raffaele O9:3 Miasnikova, Anna P2:68 Micciulla, Samantha P1:64 Michailova, Viktoria O4:13,

P2:86 Michel, Aude O6:5 Miguel, Maria da Graça O6:4,

P3:99, PLate10

Mihut, Adriana O3:1 Mihut, Adriana M. P2:34* Mikhael, Jules P2:35* Mikhailovskaya, Alesya P2:74* Milani, Silvia P3:64* Milanovic, Jadranka P3:65* Mileva, Elena O4:13,

P1:42*, P2:100*, P2:86

Milinkovic, Kristina O3:5* Miller, Kathryn P3:115*

462


Miller, Reinhard OC:3*, P1:83, P2:108*, P2:74, P2:75*

Milyaeva, Svetlana Plate:8 Miranda, Paulo P1:108 Mishrif, Marwa R. P3:35 Mitchell, Edward P3:120 Miyasaka, Keiichi P3:16 Moehwald, Helmuth P1:87 Moghaddam, Minoo O2:2 Moghaddam, Mojtaba Mirhosseini

P3:22

Moeller, Martin Plate:7 Mognetti, Bortolo KN7 Mohamed, H. M. P3:35 Mohanty, Priti P2:22,

P2:36* Möhwald, Helmuth P2:69 Mokhtari, Tahereh P1:43* Mondain-Monval, Olivier O4:3 Monduzzi, Maura BLS3*,

O8:1, P3:66*

Monopoli, Marco P3:64 Montalvo, Gemma P2:37* Monteillet, Helene P3:98* Montesarchio, Daniela P3:102 Monteux, Cecile P1:36 Montis, Costanza P3:116*,

P3:67* Morales, Veronica L. P2:117* Moran, Maria del Carmen P3:99* Morbidelli, Massimo P2:24 Morga, Maria P2:38*,

P2:41 Morimoto, Satoshi P3:43 Morishita, Taku P1:109 Moro, Solenn P2:39* Morozova, Olga P3:11 Mortensen, Kell P2:149*,

P3:108 Mosalam, Mostafa Ali O8:4 Mosca, Monica P3:100* Mosgaard, Lars D. P2:114 Mosquera, V. P2:7 Moth-Poulsen, Kasper P1:116 Mourran, Ahmed Plate:7 Mravec, Filip P2:130 Mulder, Fokko P2:140 Mulet, Xavier O2:2 Müller-Buschbaum, Peter P2:68 Mulvaney, Paul OC:17 Muñoz-Espí, Rafael O6:11* Muramatsu, Atsushi O6:3,

P1:97 Mureşan, Laura O4:10 Muresan, Laura P2:60

Murgia, Sergio O8:1*, P1:100

Murphy, Ciaran P2:80 Mutch, Kevin J. P2:6 Mzareulishvili, Natia P1:78 Naderi, Fereshteh P3:68* Nagao, Daisuke P3:30* Nägele, Gerhard P2:22 Nakagawa, Yasuharu P1:95* Nakahara, Hiromichi P1:113,

P1:96*, P1:97*, P3:74

Nakajima, Kazuya P3:31* Nakamura, Shohei P1:97 Nakaya, Masafumi P1:97 Nakazawa, Hiromitsu P1:95 Nanikashvili, Pilkhaz P2:5 Nappini, Silvia OC:13 Narayanan, Theyencheri P3:120 Narita, Takayuki P1:98*,

P3:69 Narvekar, Sneha PLate:9* Nedeljkovic, Jovan M. P2:123 Neicke, Thomas P3:32* Nelson, Adrienne O9:3,

P1:44* Nelson, Andrew P1:63 Nemeth, Silke P3:33* Neri, Wilfrid P3:28 Nestler, Peter O4:8,

P2:63 Neto, Chiara P1:37 Neubauer, Ralph O7:6 Neuber, Matthias P3:78 Neugirg, Benedikt P3:24 Neumann, Tanja P3:32 Nguyen, Le Anh Thu P2:92 Nguyen-Kim, Viet P1:45* Ni, Ran O3:14 Niaura, Gediminas P3:26 Nicol, Erwan O2:8 Nicolai, Taco O2:8 Nicotera, Isabella P1:85 Nielsen, Thomas E. Plate:13 Nikitin, Egor P2:74 Nikolov, Ljubomir P1:42 Nilsson, Christian O8:4 Nilsson, Lars KN4*,

P2:83, P3:42

Nilsson, Lena P1:22 Nilsson, Staffan O8:4* Niman, C. O6:1 Nipiè, Damijan P1:30 Noemi, Baldino P2:16 Nogueira, Daniele R. P3:99 Nogueira, Vanessa O4:5 Noirjean, Cécile P3:34*

463


Nollet, Maxime P3:101* Nolting, Frithjof P3:109 Nomoto, Tomonori O2:7,

P1:122, P1:47, P1:60

Nonomura, Yoshimune O1:3*, P1:46*

Noor El-Din, M.R. P3:35* Nørgaard, Kasper P1:116 Noskov, Boris P2:74 Nowacka, Agnieszka O2:10,

P3:52 Nyikos, Lajos P1:53 Nyk, Marcin P3:47 Nylander, T. O6:1 Nylander, Tommy O9:4,

O9:6, O4:12, P1:22, P1:5, P1:74, P3:84, P3:116, P3:119

Nystrom, Bo P1:5 Oæwieja, Magdalena P2:38,

P2:41* Oberdisse, Julian O6:12* Obiols-Rabasa, Marc P2:42* O'Connell, Maria P1:80 Oder, Martina P1:30 Odnevall Wallinder, Inger P1:6 Ogonowski, Jan P3:20 Oguey, C PL1 Ohtomi, Eisuke P1:61 Oishi, Yushi P1:98,

P3:69* Okada, Ayako P3:30 Okoli, Chuka OC:12 Okoye, Adaora P2:111 Okuno, Keita P3:36* Oliviero Rossi, Cesare P2:16 Ollila, Samuli P1:99* Olsson, Ulf P1:100,

P1:117, P1:79, P1:91, P2:2, P2:45, P3:108

Oltmanns, Jens O6:9 Orban, Sebastian P2:76* Orsi, Davide KNC:1 Ortega, Francisco O1:11* Ortmann, Thomas P3:117* Ose, Velta P2:119 Oshima, Hideaki P2:118* Oshima, Shogo P1:47*

Osterbacka, Ronald P1:94 Østergaard, Jesper P2:148 Ota, Masahiro P1:95 Ouazzani, Jalil P2:103 Overgaard, Anne Kathrine K. Plate:13 Oye, Gisle P1:20 Ozmen, Mustafa P3:10,

P3:37*, P3:50, P3:9

Oztekin, Yasemin OC:24, P2:146

Paboeuf, Gilles P3:118 Padding, Johan O3:5 Paduano, Luigi O4:1.

P3:102* Pais, Alberto O4:5 Pajor-Swierzy, Anna P3:25 Pajuste, Karlis P2:119 Palacci, J. KN8* Palazzo, Gerardo P1:100*,

P3:62, P3:70*

Pantoustier, Nadege P1:36 Papadakis, Christine P2:68 Papadakis, Christine M. O4:9 Papadimitriou, Vassiliki OC:21,

P3:58, P3:83

Papadopoulos, Periklis O1:12*, P1:48*

Papastavrou, Georg O4:10, P1:34

Para, Andrzej P2:89 Para, Grazyna P2:89 Park, Hyunji OC:20* Parker, Roger P3:5 Parkin, Ivan P. OC:22 Parlange, Jean-Yves P2:117 Paroor, Harsha P1:121 Parsons, Drew OC:7* Parsons, Drew F. P2:8 Partch, Richard Plate:15 Pasc, Andreea P3:38* Pasco, Maryvonne P3:118 Pashinin, Andrey P3:7 Pasquier, Coralie P3:118* Patkowski, Jacek P2:77* Paul, Alexis P2:79 Paulsson, Marie P1:22 Pavel, Nicolae V. P1:117,

P1:89 Pavel, Nicolae Viorel O2:11 Pavel, Viorel P3:44 Pazos, Carmen P3:92,

P3:97 Pechar, Michal P2:87

464


Peddireddy, Karthik Reddy P1:49* Pedersen, Ida Dalgaard P1:9 Pekaø, Miloslav P2:130,

P2:132, P2:133*

Pelan, Edward P1:21 Peltonen, Jouko P1:94,

P3:21 Pemartin, Kelly OC:12,

P2:141 Penfold, Jeffrey O2:3 Penicaud, Alain P3:28 Percebom, Ana Maria P1:102* Perera, Jilska P1:50* Perez, Javier P3:118 Perez-Carrillo, Lourdes A. P2:137 Pérez-Fuentes, Leonor P1:4 Perni, Stefano OC:22,

P2:145 Perrin, Patrick P1:36 Petersen, Asger B. P3:119* Petkov, Jordan O2:3 Petkova, Yana P3:82 Petricenko, Oksana P2:119 Petri-Fink, Alke P3:89 Petrova, Liliya P3:71* Petrovic, Lidija P2:131,

P3:65 Pettersson, Carmen P3:32 Pettersson, Torbjorn P2:78* Pettersson, Torbjörn O1:16 Peukert, Wolfgang P2:21 Pezennec, Stéphane P3:118 Pham, Quoc Dat Plate:6* Philipse, Albert O3:11,

P1:12, P1:65, P2:11, P3:87

Phillip, Martine P2:68 Pich, Andrij O3:13,

P1:28, P2:9, P3:39*, P3:48, P3:81

Piculell, Lennart O9:4, P1:102, P2:61, P3:119

Piekoszewska, Joanna OC:16 Pigliacelli, Claudia P1:101* Pihl, Maria O1:8* Pilat, Dominik O1:1* Pimienta, Véronique O1:2* Pine, D.J. KN8 Piñeiro, Ángel P1:8 Pinzer, Bernd Rupert P3:113

Piotrowski, Marek P2:88 Piret, G. O6:1 Pirolt, Franz OC:15 Pizzey, Claire O2:12,

P2:48 Plamper, Felix P3:48 Plotniece, Aiva P2:119* Plotniece, Mara P2:119 Podgórna, Karolina P2:88 Podor, Renaud P3:93 Poggi, Giovanna P3:14 Pogodin, Sergey O7:7 Pojják, Katalin P2:124 Polarz, Sebastian P1:87 Politova, Nadia P2:18 Polzer, Frank P1:82 Pommella, Angelo Plate:1 Poncet-Legrand, Céline P2:10 Pongkitwitoon, Benyakan P3:43 Pontoni, Diego O9:1*,

O9:3, P3:120*

Popa, Ionel O4:10 Popp, Alois P2:79* Porcar, Lionel O9:5 Portnaya, Irina P1:103* Porus, Maria O4:10 Pothecary, Mark P2:80* Poulin, Philippe P3:28 Poulopoulou, Marilena OC:21 Pozar, Josip P2:144 Preska Steinberg, A. KN8 Prevost, Sylvain O2:5*,

O2:9 Prévost, Sylvain P3:107 Preziosi, Valentina Plate:1 Prinz, C.N. O6:1 Procek, Jan PLate:6 Prochaska, Krystyna P1:104*,

P1:16, Plate:2

Prochazka, Karel O2:9 Prokopovich, Polina OC:22*,

P2:145* Proskurina, Victoria P2:43* Puaud, Fanny O2:8* Pucci, Carlotta P1:105* Puertas, Antonio M. P2:44 Pulkkinen, Petri P1:94 Puretskiy, Nikolay O1:13*,

O3:8, P1:51*

Qamhieh, Khawla O4:12* Qi, Sheng P1:101,

P1:80 Queiroz, João Plate:10 Quilliet, Catherine P3:1 Radulescu, Aurel P3:102 Radulova, Gergana OC:2

465


Raedler, Joachim P3:64 Raessi, Sabet P3:68 Ragab, Ahmad M. P3:35 Rahn-Chique, Kareem P2:44* Raimondi, Laura P1:39 Rajarao, Gunaratna Kuttuva OC:12 Rakowska, Joanna P1:104 Ramanaviciene, Almira OC:24,

P2:134, P2:146*

Ramanavicius, Arunas OC:24*, P2:134*, P2:146, P3:26

Ramsch, Roland P2:81* Rappolt, Michael P2:122,

P2:148 Ras, Robin H. A. P1:32 Ras, Robin H.A. P1:25 Raspor, Peter P1:30 Ratautaite, Vilma OC:24 Ravaine, Valerie O1:17,

P3:76 Ravaux, Johann P3:93 Ravera, Francesca P2:105,

P2:109*, P2:143

Reck, Bernd P2:24 Regev, Oren O2:11,

P1:89 Reichardt, Nina P1:5 Reichert, Harald O9:1 Reimer, Johan P2:98 Reimhult, Erik O9:3 Reshetova, Elena P1:52* Restagno, Frederic P1:56 Reviakine, Ilya P3:72* Richardt, Andre O7:6 Richter, Marina Juliane P3:73* Richtering, Walter P1:27 Ridi, Francesca P3:12,

P3:3, P3:40*, P3:41*

Riehle, Mathis O6:13 Rigault, Sophie P3:118 Rio, Emmanuelle P1:56 Rios, Cesar P2:82* Ristori, Sandra P1:106* Roach, Peter L. Plate:13 Roblin, Pierre P2:10 Roger, Kevin P2:45*,

P2:46* Roig, Ferran P1:107* Rojas, Clara P2:44 Roke, Sylvie KN2*,

P1:110 Röling, Christian P3:78 Rojewska, Monika Plate:2*

Romanszki, Lorand P1:53* Romero-Cano, Manuel S. P2:44 Ronneburg, Hendrik P3:109 Rosencrantz, Ruben R. OC:20 Rosenholm, Jarl B. BLS5* Rothen-Rutishauser, Barbara P3:89 Ruan, Juanfang P3:23 Rubio, R G OC:1 Rubio, Ramon G. P2:110 Rubio Retama, Jorge P2:71 Rubio-Retama, Jorge KNC:2*,

OC:5, P2:51

Rucins, Martins P2:119 Rühl, Eckart P3:109 Rühm, Adrian P2:69 Rukhadze, Marina P1:78 Runyon, J. Ray P2:83*,

P3:42* Ruocco, Giancarlo P3:105 Ruso, Juan M. P1:54* Rutland, Mark O1:18*,

P1:10 Rutland, Mark W. P1:23 Ruzgas, Tautgirdas P1:35,

P3:11, P3:26, P3:56

Ruzicka, Barbara P3:105 Saadaoui, Hassan O3:9,

P3:51 Sabadini, Edvaldo P1:108* Sacanna, S. KN8 Sadeghpour, Amin OC:15* Sagnella, Sharon O2:2 Sainiemi, Lauri P1:32 Sakai, Hideki P1:109 Sakai, Kenichi P1:109 Sakamoto, Kazutami P1:109* Sakamoto, Seiichi P1:113,

P1:97, P3:43*, P3:74*

Sakamoto, Yasuhiro P3:23 Salazar-Alvarez, German O9:2 Salis, Andrea P3:66 Salvati, Anna O6:2,

P3:64 Salvucci, Anthony E. P2:117 Samoc, Marek P3:47 Samuelson, Lars PL2* Sanchez, Christian P2:33 Sanchez-Dominguez, Margarita OC:12* Sanchez-Dominguez, Margarlta P2:141* Sanchez-Ferrer, Antoni O9:3 Sander, Jonathan O8:2*,

O3:7* Sang, Wenjing P2:117 Sanson, Nicolas P2:39

466


Santini, Eva P2:105,

P2:109, P2:143

Saponjic, Zoran V. P2:123 Sarac, Bojan P2:115,

P2:120* Sarkar, Jayati P1:55* Sartori, Barbara P2:122 Satoh, Akira P2:47* Sauerbeck, Christian P2:21 Saulnier, Laurie P1:56* Saunders, Brian R P2:135 Sauvage, Francois-Xavier P2:10 Savic, Tatjana D. P2:123 Sawada, Hideo P2:84*,

P3:36, P3:45, P3:46

Schaaf, Pierre P2:82 Schaefer, Thorsten P1:11 Schaeffel, David O1:15* Scheu, Rüdiger P1:110* Schiedt, Birgitta P3:63 Schillén, Karin P1:117,

P1:5, P3:44* O2:11 O9:4, P1:102

Schipper, Oliver P2:127 Schlüter, A. Dieter P2:60 Schmidt, Annette P1:90 Schmidt, Claudia P1:82 Schmidt, Hans-Werner P3:24 Schmidt, Jochen P2:21 Schmidt, Judith O8:1 Schmidt, Karin P3:75 Schmidt, Ulrike S. P3:75* Schmiele, Martin P3:121*,

P3:96 Schmitt, Mechthild P2:148 Schmitt, Murielle P2:125* Schmitt, Veronique O4:3*,

O1:17, P3:103*, P3:76*

Schmitt, Véronique P3:101 Schmitz, Roman O1:15 Schneebeli, Martin P3:113 Schneider, Rene P3:86 Schofield, Andrew P3:90 Schön, Sebastian PL4 Schönhoff, Monika P1:84,

P2:23, P2:76

Schouenborg, Jens P3:11 Schroen, Karin O3:10 Schubert, Ulrich S. O6:8

Schuchmann, Heike P. P3:75 Schuerings, Marco Phillipp P3:48 Schulreich, Christoph O7:6 Schulz, Alexander P3:73 Schulze, Anita O4:9 Schürings, Marco-Philipp O3:13* Schurtenberger, Peter O7:2,

O3:1, P2:1, P2:22, P2:34, P2:36, P2:42

Schwaneberg, Ulrich P3:81 Schwartz, Daniel O7:1 Schwebler, Linda O3:2 Schweins, Ralf O6:12 Schwieger, Christian O2:1* Scipioni, Anita P1:105 Seguineau de Preval, Eungenie P1:41 Seino, Eri O1:3 Šejnohová, Michaela P2:130 Selivanova, Natalia P1:111* Sellier, Elisabeth P3:76 Semenov, S OC:1 Semenov, Sergey P2:110,

P2:111 Senden, Tim J. O4:2 Sennato, Simona P1:117,

P1:89 Sergeeva, Yulia P2:85* Serrano-Ruiz, David OC:5 Seto, Hiroshige P3:69 Setyamukti, Howard O4:4 Shagieva, Farida P2:101* Shahidan, Nur Nabilah P2:135* Shakesheff, Kevin M P2:135 Sharipova, Altynay P2:75 Sharma, Suraj P1:112* Shebanova, Olga O2:12 Shen, Xiantao P2:147* Shibata, Osamu P1:113*,

P1:96, P1:97, P3:43, P3:74

Shikhobalova, Oxana P1:111 Shilova, Svetlana P2:56 Shleev, Sergey P1:35,

P3:11 Siegel, Günter BLS2* Sikora, Elzbieta P3:20 Silva, Bruno F.B. P3:108 Singer, Julia P3:24 Singh, Rajdeep G. P1:115 Singh, Sukhprit P2:113 Sjöblom, Johan BLS6*,

P1:33 Skantze, Urban P2:2

467


Skepö, Marie O4:11*,

O1:8, P2:64

Skoda, Maximilian P3:115 Skorb, Ekaterina V. P3:33,

P3:6 Skrivele, Baiba P2:119 Skrobanska, Ralica OC:23 Slomkowski, Stanislaw P2:53 Slot, J.J.M. P2:29 Sloutskin, Eli P2:5 Smallenburg, Frank O3:14 Smith, Gregory P3:122* Sobolev, Arkadij P2:119 Socha, Robert P. OC:16 Soklev, Borislav O4:13*,

P2:86* Solans, Conxita OC:12,

P1:107, P2:137, P2:141

Soliveri, Guido P1:40 Soltwedel, Olaf O4:8,

P3:123* Son, Young-A P2:30 Sørensen, Martin B. PLate:13 Soto Tellini, Victor Hugo O2:11 Sotres, Javier O7:5*,

P2:102, P3:11

Souma, Saki P3:45* Sovilj, Verica P2:131,

P3:65 Sow-Hsin, Chen P3:12 Spadaro, Fabiana P3:41 Sparr, Emma O2:10*,

P1:43, P3:52, P3:57

Spencer, Nicholas D. P1:44 Spiecker, Erdmann P3:17 Stajner, Lara P2:144 Stamm, Manfred O1:13 Stampanoni, Marco P3:113 Starov, Victor OC:1*,

P2:110*, P2:111, P2:112

Starovoytova, Larysa P2:87 Stébé, Marie-José P3:38 Steenhuis, Tammo S. P2:117 Stef, van der Meulen KN7 Stehle, Ralf P3:106,

P3:107 Steinbock, Oliver O1:2 Steitz, Roland P1:64,

P3:107 Stepanek, Miroslav O2:9

Stepanyan, R. P2:29 Stéphane, Viville P2:85 Steudle, Anne P3:77 Stevens, Geoff P1:50 Stevenson, Paul O2:3 Stilke, Carl P2:4 Stîngă, Gabriela P2:53 Stoyanov, Simeon OC:2,

P1:21, P3:71, P3:82

Stoychev, Georgi O1:13 Stradner, Anna O7:2 Strey, Reinhard P1:67 Stubenrauch, Cosima P3:127 Studart, Andre R O8:2,

O3:7 Studart, André R. O1:4 Stumpf, Patrick P3:109 Sturcova, Adriana P2:87* Subinya Albrich, Mireia P3:77* Sugimoto, Maki P3:30 Sugiya, Masashi P3:45 Sukenik, Shahar OC:14* Sutanto, Stevia P1:57* Suyatin, Dmitry P3:11 Suzuki, Ken-ichiro P2:118 Svendsen, Winnie P2:72 Svensson, Anna V. PLate:1* Svensson, Olof O4:11,

O7:5, P1:58*

Swenson, Jan P2:66 Swerin, Agne O1:10 Synytska, Alla O1:13 Szczepanowicz, Krzysztof P2:67,

P2:88*, P2:89*

Sztucki, Michael P3:120 Szyk-Warszyñska, Lilianna OC:16*,

P2:67 Szymanski, Lukas P3:127 Taccardi, Nicola P3:17 Tadros, Tharwat P2:1 Takahashi, Yutaka P1:114*,

P3:31 Takeda, Ken P2:118 Takiue, Takanori O1:14*,

P1:26, P1:38, P1:59, P1:61

Takumi, Hiroki P1:26, P1:59*

Talmon, Yeshayahu KN6*, O8:1

Tanaka, Hirioyuki P3:43 Tanaka, Motomu PL3* Tanaka, Ryo P1:60*

468


Tanida, Hajime O1:14,

P1:26 Taniguchi, Retsu P2:118 Tanizaki, Yusuke P3:43 Tao, Wendy P1:50 Tardani, Franco P2:90* Tatou, Mouna O6:12 Tatsuta, Kazuo O1:14 Tavacoli, Joseph O8:3 Tayati, Ponlawat O4:2* Tcholakova, Slavka P1:21,

P2:18, P3:71, P3:82

Tehrani-Bagha, Ali Reza P1:115*, P1:116*

Teixeira, Jose P3:114 Teixidor, Francesc O2:5 Telegdi, Judit P1:53 Tempesti, Paolo P3:3 Tenhu, Heikki P1:94 Terasaki, Osamu P3:16 Terrill, Nicholas O2:12 Testard, Fabienne P3:34 Thanh, Nguyen T K P3:27 Thiesen, Peter H. P3:78* Thies-Weesie, Dominique P2:11 Thomas, Robert O2:3 Thormann, Esben O1:10*,

P1:10, P1:13

Thorn, Christian P3:15 Thuresson, Krister P2:99 Thurston, George O7:2 Thutupalli, Shashi P1:49 Tiberg, Fredrik P2:94 Tieleman, D. Peter O2:6 Tisserand, Christelle O3:4 Tobin, Mark O7:7 Toca-Herrera, José O4:14 Toccafondi, Nicola P3:14 Tolker-Nielsen, Tim PLate:13 Tokiwa, Yuhei P1:61* Topgaard, Daniel O2:10,

P1:99, P2:98, P3:52, P3:8

Torngren, Bjorn P1:94 Torsi, Luisa P3:62,

P3:70 Totsche, Kai Uwe PLate:9 Tottori, Takuya O1:14 Touraud, Didier O1:5,

OC:6, P3:94, P3:95

Toyota, Taro O2:7, P1:122, P1:3, P1:47, P1:60

Trägårdh, Christian P1:22 Travaglini, Leana P1:117* Tret'yakova, Alla P2:56 Trillo Novo, Juan O2:11 Tromp, Hans O1:9*,

P1:65 Tropel, Philippe P2:85 Truong, Vi Khanh O7:7 Trybala, A OC:1 Trybala, Anna P2:111* Tschierske, Carsten O2:1 Tse, Nicholas O2:2 Tsuzuki-ishi, Taiki P3:46* Tucker, Ian O2:3 Tuinier, R. P2:29 Tuinier, Remco P1:76,

P2:28 Turner, Sarah T. OC:17 Turq, Pierre P3:114 Tutus, Murat P3:53 Twardochleb, B P1:104 Tyowua, Terhemen Andrew P3:104* Tyrode, Eric P1:62* Uchiyama, Koyo O2:7 Uchman, Mariusz O2:9* Uddin, Khan Mohammad Ahsan P2:147 Ullah, Asmat P2:112* Ulvenlund, Stefan P2:98 Unal, H. Ibrahim P2:126*,

P2:136 Ungar, Goran O6:3 Unruh, Tobias P3:121,

P3:124*, P3:96

Unsal, Hande P1:72 Urbanczyk-Lipkowska, Zofia P2:107 Urbina-Villalba, German P2:44 Urtti, Arto P2:148 Uruga, Tomoya O1:14 Utsel, Simon O1:16 Üzüm, Cagri O4:4*,

PL4 v. Klitzing, Regine PL4* Valente, Artur PLate:10

* Valero, Edelmira P2:71 van Blaaderen, Alfons O3:14 van de Weert, Marco P3:60 van Duijneveldt, Jeroen P2:48* van Rijn, Patrick P3:53 van Rijssel, Jos O3:11 Vandoolaeghe, Pauline P3:80* Varga, Imre O9:6,

O1:7*

469


Vargas, Ariel Alfaro O2:11 Varol, Hasan Samet O6:11 Vázquez Tato, José O2:11 Vela-Gonzalez, Andrea-Victoria P2:141 Veljkovic, Dusan Z. P2:123 Venediktova, Anastasia O2:4* Verdinelli, Valeria P1:54 Vereda, F. P2:7 Verho, Tuukka P1:32 Vernhet, Aude KN9a*,

P2:10 Victoria, Dutschk P2:129 Victorov, Alexey P1:118* Vidal, Laia P3:99 Videnichev, Dmitry O2:4 Vilchez, Susana P2:137 Vilgis, Thomas A. P3:63 Vinardell, Maria Pilar P3:99 Vinarov, Zahari P3:71,

P3:82* Vincent-Bonnieu, Sébastien P2:125 Viot, Philippe O4:3 Vis, Mark P1:65* Visnevskij, Ceslav P1:10 Vitasari, Denny P3:59 Vitorazi, Letícia P1:120* Vleugels, Leo F.W. P2:28 Vogt, Cedric P2:82 Vogt, Otmar P2:25 Volkov, Alexey P1:19 Vollhardt, Dieter P1:83 Vollmer, Doris O1:6*,

P1:121*, P1:48

von Klitzing, Regine O4:4, P1:64

Voroanovic, Jaroslav OC:24 Vorobiev, Alexei P3:120 Vysotsky, Yuri P1:83 Wacklin, H.P. O6:1 Wacklin, Hanna P2:107,

P3:79* Waddington, Lynne O2:2 Wadsäter, Maria OC:18 Wadsö, Lars O2:10 Wågberg, Lars P2:78 Wågberg, Lars O1:16* Wagner, Dana O7:3 Wagner, Norman O9:5*,

P3:125* Wakeham, Deborah O1:18,

P1:23, P1:63*

Walder, Robert O7:1 Wallgren, Marcus PLate:6 Wang, Huihui P3:81* Wang, James O7:7 Wang, Min P1:13* Wang, Xin P1:6

Warmoeskerken, Marijn P2:129 Warr, Gregory P1:112 Warr, Gregory G P1:63 Warszynski, Piotr OC:16,

P2:106, P3:25

Warszyñski, Piotr P2:67, P2:88, P2:89

Wasbrough, Matthew J. KN1 Waschatko, Gustav P3:63 Watanabe, Iwao P1:26 Watson, Gregory O7:7 Watson, Jolanta O7:7 Webb, Hayden O7:7 Wedel, Bastian P2:127* Wei, Dan P2:24 Wei, Shih-Chung P3:55 Weitz, David O3:14 Welbourn, Rebecca P1:66,

P3:115, P3:126*

Wellert, Stefan O7:6, P1:64*, P3:127*

Weng Larsen, Susan P2:148 Wennerstrom, Hakan P2:31 Wennerström, Håkan O2:10 Wernersson, Erik PLate:11 Werzer, Oliver O1:18 Weschke, Eugen P3:109 Wessling, Matthias P2:92,

P3:53 Westbye, Peter P3:56 Wetterskog, Erik O9:2 Wiklund, Johan P1:22 Wikström, Jennie P2:91* Wilde, Pete P1:101 Wilhelm, Claire P3:93 Wilk, Kazimiera A. P1:119*,

P2:106, P3:2, P3:47*, P3:85

Willenbacher, Norbert O3:2 Witwicki, Maciej P1:119 Wohlleben, Wendel P2:35 Wojciechowski, Kamil P2:121* Wöll, Christofer OC:25 Won, Jooyoung OC:3 Wong, John Erik P2:92* Wood, Mary P1:66* Woodward, Clifford E. P2:14 Wu, Hua P2:24 Wu, Mingming P2:117 Wuennemann, Patrick P3:48* Wulff, Nadja P1:67* Wünnemann, Patrick O3:13

470


Xenakis, Aristotelis OC:21*, P3:58, P3:83*

Xie, Fei O4:7 Xie, Junjie O6:7 Xu, Changgang P2:147 Yaghmur, Anan P2:122*,

P2:148* Yaguchi, Tatsuya P1:122* Yamamoto, Yuki P1:114 Yanez Arteta, Marianna O9:4*,

O9:6, P3:84

Yang, Qingbo P2:93 Yao, Hiroshi P3:49* Yasemin, Oztekin P2:134 Ye, Lei P2:147 Yethiraj, Anand P2:36 Yildiz, Salih P3:50* Yoon, Kisun O3:14 Yordanov, Georgi OC:23*,

P2:139 , PLate:14

Yordanov, Stoyan O1:15 Yoshida, Amika P2:118 Yoshida, Masato P2:84,

P3:36, P3:46

Yoshikawa, Yoichiro P2:118 Youssry, Mohamed P1:85 Yunda, Elena PLate:8,

PLate:12*

Yushkin, Alexey P1:19 Zabiegaj, Dominika P2:109 Zaccarelli, Emanuela KN5* Zaccone, Alessio O3:12* Zakri, Cécile P3:28 Zarbakhsh, Ali P1:66,

P3:126 Zaric, Snezana D. P2:123 Zeiser, Michael P2:127,

P2:128* Zemb, Thomas O2:5,

O1:5, OC:6*, OC:9, P1:81

Zeng, Xiangbing O6:3 Zeng, Yan PL4 Zhang, Baozhong P2:60 Zhang, Jianqi O4:9 Zhang, Wei P2:117 Zhao, Jiang P2:93* Zhao, Jie P2:129* Zhigunov, Alexander P2:87 Zhu, Kaizheng P1:5 Zirbs, Ronald O9:3

Zitoun, David P2:5 Znamenskaya, Yana P2:102* Zoumpanioti, Maria P3:83 Zulian, Laura P3:105 Zunke, Christoph O3:3

471

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