physics and chemistry of hybrid organic-inorganic materials lecture 5: naturally occurring hybrids
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Physics and Chemistry of Hybrid Organic-Inorganic Materials
Lecture 5: Naturally occurring hybrids
Biological hybrids: key points
• Hybrids made by plants or animals• Strong composites from very weak components
– Wet protein and carbohydrates are very soft– calcium carbonate is also weak and soft
• Multiple phases, hierarchical structures
Hybrid Organic-Inorganic materials are common in nature: composites
Nacre
Argonite (CaCO3) plates as inorganicwith protein (polyamide) as organic
Animals
Plants
phytolith
Teeth, spines in echindermsMussel shells, sponges, diatoms and corals are utilize hybrid organic-inorganic materials
Organic phase is biopolymers
Carbohydrates are the template and organic phase
What is a hierarchical structure?
In materials, a structure with different structures at different length scales: like in tendons (above)
The Building PlanFabrication Conditions in Living Organisms
only few elements: C, H, O, N, P, S, Ca, Si, Mg
mild pH
ambient pressure and temperature
Calcite Crystals Extracted from the Prismatic Layer of Pinna Nobilis Shells
www.cutgana.it/acquario/specie Marin et al., J. Biol. Chem., 2005, 40, 33895
The Building Plan
Hierarchical Design – Morhpology Control on Several Levels
Interaction of an Organic and an Inorganic Component
Fabrication Conditions in Living Organisms
only few elements: C, H, O, N, P, S, Ca, Si, Mg
mild pH
ambient pressure and temperature
Incorporation of biopolymers increased fracture resistence
&
aspartate residue in peptide bond
chitin network
Nudelman et al., Faraday Discuss. 2007, 136, 9
Colloidal silica in diatoms: Hierarchical structure
Silica walls are build up from ca. 5nm particles to give ca. 40nm diameter particles that are organized within the frustule.
pH ≈ 5
Silica (SiO2) & protein
radiolaria diatoms
Proteins act as templates for building silica architectures
Bio-Hybrids based on CaCO3: NacreArgonite (CaCO3) plates as inorganic phasewith protein (polyamide) as organic phase
Mother-of-pearl
Opalescence from light diffraction in nacre (argonite blocks height ≈ λ light)
Fracture strength is 3000 times higher than its mineral constituent CaCO3.
The hierarchical structure of nacre
Barthelat F Phil. Trans. R. Soc. A 2007;365:2907-2919
argonitecrystalstructure
Phasemorphology
Long range order: stacked crystals
Growth rings (mesolayers)
Macromolecular
Inner surface of shell (mother or pearl)
The shell itself
Lobster exoskelton
CaCO3
& Carbohydrate & protein
Teeth: Enamel, dentin, & cementum
Apatite – hydrated CaPO4
Protein– collagen & others
The layered, rod structure of hydroxyapatite (a calcium phopshate) in dental enamel. Very tough for a ceramic.
Hierarchical structure of alligator gar, a primitive fish, scales. Ganoine is mostly mineral, like enamel, with tougher bone beneath.
Enamel and collagen
Regular Fish Scales
Fish scale puncture resistance
fish scales are better than polycarbonate.note how they give, and then reload. This is just one scale.
200 MPa yield strength 30 MPaM0.5 toughness
Apatite – hydrated CaPO4
Protein– collagen
Bones
The Building Plan
Hierarchical Design – Morhpology Control on Several Levels
Interaction of an Organic and an Inorganic Component
structural optimization from the atomic to the macroscopic scale
Fabrication Conditions in Living Organisms
only few elements: C, H, O, N, P, S, Ca, Si, Mg
mild pH
ambient pressure and temperature
&
Bone
Fratzl et al., Progr. Mat. Science, 2007
Peterlik et al., Nat. Mat., 2006
Gupta et al., PNAS, 2006
Echinoderm spine
CaCO3
Protein templating
Phytoliths
Horsetail, banana leaves
2-3% silicon by weight
SiO2 silica
Silica in Sponges
Templated by proteins
hierarchical structures
Euplectella sp.
7 hierarchical levels
Stress-deflection responses of synthetic silica rod and sponge spicule in flexuretesting. (Courtesy of M. Sarikaya and G. Mayer.)
conch shell Almost no protein 3 hierarchical levels of layers made from layers of calcite.
Chiton Teeth
the tips of the teeth are hard magnetite (Fe3O4) with a tough fibrous calcite interior
Metal in Spider Fangscarbohydrate fibers in a protein matrixwith zinc and magnesium ions
Politi, Y., Priewasser, M., Pippel, E., Zaslansky, P., Hartmann, J., Siegel, S., Li, C., Barth, F. G. and Fratzl, P. (2012), A Spider's Fang: How to Design an Injection Needle Using Chitin-Based Composite Material. Adv. Funct. Mater., 22: 2519–2528
Biomaterial: Toucan Beak
(a) Toucan beak; (b) external shell made of keratin scales. Cellular materials: (a) synthetic aluminium foam; (b) foamfound in the inside of toucan beak.(Courtesy of M. S. Schneider andK. S. Vecchio.)
Bio Hybrid Organic-Inorganic MaterialsSophisticated, highly evolved hybrids
-nominally weak, but bio-accessible minerals (eg. CaCO3)-hydrophilic, water plasticized biopolymers (eg. protein) -Integrated at nano-length scales-Phase separation templating of hierarchical structures-All water based chemistry!! The ultimate green
chemistry
Optimized to give non-additive property (synergistic effects)
Models for many research programs in hybrid materials