delayed freezing of water droplet on silver nanocolumnar film

8/12/2019 delayed freezing of water droplet on silver nanocolumnar film

1/5

Highly sensitive superhydrophobic Ag nanorods array substrates for surface enhanced

fluorescence studies

Samir Kumar, Pratibha Goel, Dhruv P. Singh, and J. P. Singh

Citation: Applied Physics Letters 104, 023107 (2014); doi: 10.1063/1.4861836

View online: http://dx.doi.org/10.1063/1.4861836

View Table of Contents: http://scitation.aip.org/content/aip/journal/apl/104/2?ver=pdfcov

Published by the AIP Publishing

article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. Downloaded to IP: 119.2

On: Thu, 13 Feb 2014 15:24:52
http://scitation.aip.org/search?value1=Samir+Kumar&option1=authorhttp://scitation.aip.org/search?value1=Pratibha+Goel&option1=authorhttp://scitation.aip.org/search?value1=Dhruv+P.+Singh&option1=authorhttp://scitation.aip.org/search?value1=J.+P.+Singh&option1=authorhttp://scitation.aip.org/content/aip/journal/apl?ver=pdfcovhttp://dx.doi.org/10.1063/1.4861836http://scitation.aip.org/content/aip/journal/apl/104/2?ver=pdfcovhttp://scitation.aip.org/content/aip?ver=pdfcovhttp://scitation.aip.org/content/aip?ver=pdfcovhttp://scitation.aip.org/content/aip/journal/apl/104/2?ver=pdfcovhttp://dx.doi.org/10.1063/1.4861836http://scitation.aip.org/content/aip/journal/apl?ver=pdfcovhttp://scitation.aip.org/search?value1=J.+P.+Singh&option1=authorhttp://scitation.aip.org/search?value1=Dhruv+P.+Singh&option1=authorhttp://scitation.aip.org/search?value1=Pratibha+Goel&option1=authorhttp://scitation.aip.org/search?value1=Samir+Kumar&option1=authorhttp://oasc12039.247realmedia.com/RealMedia/ads/click_lx.ads/www.aip.org/pt/adcenter/pdfcover_test/L-37/1159426268/x01/AIP-PT/APL_ArticldDL_012214/aipToCAlerts_Large.png/5532386d4f314a53757a6b4144615953?xhttp://scitation.aip.org/content/aip/journal/apl?ver=pdfcov


2/5

Highly sensitive superhydrophobic Ag nanorods array substrates for surfaceenhanced fluorescence studies

Samir Kumar, Pratibha Goel, Dhruv P. Singh, and J. P. Singha)

Department of Physics, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India

(Received 15 October 2013; accepted 21 December 2013; published online 14 January 2014)

We report a facile method to fabricate highly sensitive superhydrophobic Ag nanorods (AgNR)

arrays based surface enhanced fluorescence spectroscopy (SEFS) substrates using glancing angledeposition technique at a substrate temperature of 133 K and then subsequent coating of

heptadecafluoro-1-decanethiol (HDFT) molecules. The SEFS enhancement behaviour of these

substrates was determined by using aqueous solution of Rhodamine 6G. The HDFT coated

superhydrophobic AgNR arrays SEFS substrates exhibit more then 3-fold fluorescence signal

enhancement than conventional AgNR films. These HDFT coated superhydrophobic AgNR

SEFS substrates based sensors may find application for the purpose of trace analysis and

biosensing. VC 2014 AIP Publishing LLC. [http://dx.doi.org/10.1063/1.4861836]

Superhydrophobic surfaces having contact angle more

than 150 has been a topic of great interest of many research-

ers because of its potential applications in anti-biofouling

paints for boats,1 anti-sticking of snow for antennas,2 self-

cleaning of windshields,3 anti-icing,4 anti-corrosion,5 and in

the field of spectroscopy too.6 Superhydrophobic surfaces

can be fabricated either by chemically modifying the rough

surface with a low surface energy material3 or by creating a

porous or the solidair composite surface by synthesis of

micro- and nanostructures of a hydrophobic material.

Superhydrophobic surfaces have been prepared by many

researchers for various applications using glancing angle

deposition (GLAD) technique.79

GLAD has emerged as a versatile technique to grow

nanostructures ofwiderange of materials with various sizes

and morphologies.

1014

These nanostructures find importantapplications in several fields like gas sensing, optically active

films, photocatalysis, photoniccrystals, and in modifying the

surface wetting properties.1517 Recently, silver nanostruc-

tures grown by GLAD have attracted a significant interest

due to their promising applications in surface plasmon based

studies and for the fabrication of highly sensitive surface

enhanced Raman scattering (SERS) substrates.1820

Surface

enhanced fluorescence (SEF) is another surface plasmon

based phenomenon which has recently emerged as a powerful

technique to improve the fluorescence sensitivity and take the

fluorescence signals with higher contrast level.21,22 SEF is a

giant enhancement of fluorescence intensityof a fluorophore

in the vicinity of a rough metal surface.23,24

Enhancement ofmolecular fluorescence is of great interest due to its immense

application in the field of chemistry, molecular biology, mate-

rials science, photonics and medicine. For the practical appli-

cation of active SEF substrates, one of the key issues is high

enhancement ability and good stability. Till now, various

SEF active substrates have been fabricated ranging from

roughenedsilver electrodes,25 light deposited silver,26 silver

fractals,27 and deposited colloids.28 Another way to fabricate

SEF substrate is by tailoring the surface properties which

may heavily influence the intensity of SEF signal as the giant

enhancement only happen in the close vicinity of the metal

surface. Nanorods arrays were also widely used for the con-

struction of SEF substrates.19,29 Recently, fabrication of

superhydrophobic substrates for enhanced fluorescence using

optical lithography and ion-etching was reported by Gentile

and researchers.30 However, the fabrication method implied

was complex, expensive, and also technologically demanding

for the large scale production.

In this study, we report fabrication of heptadecafluoro-1-

decanethiol (HDFT) coated superhydrophobic Ag-nanorods

substrates for SEF using low temperature GLAD technique.

The HDFT coated superhydrophobic AgNR arrays susbtrates

exhibit more then 3-fold fluorescence signal enhancement

than the conventional AgNR films that may be because ofthe superhydrophobic condensation effect.31,32

Silver nanorod arrays were grown on Si(100) substrates

by thermal evaporation of silver powder (99.9%) using

GLAD.10,11,3336 Before the deposition, Si substrates were

ultrasonically cleaned in acetone. Si substrates were mounted

on the sample holder and was inclined in such a way that the

normal of the sample surface made a very high angle

(a 85) with respect to the direction of the incident vapourflux. The substrate temperature was regulated to control the

morphology of the grown Ag nanorods arrays. A customized

substrate holder with a heater and controlled supply of liquid

nitrogen was used to maintain the substrate temperature of

133 K. The temperature was measured with an accuracy of61 K using PT100 temperature sensor placed closed to the

substrate. The chamber pressure during deposition was better

than 2 106 Torr. For reference conventional Ag thin filmswere also grown with the normal incidence (a 0) of vaporflux on Si substrates. The surface morphology of the resulting

nanorods was investigated by scanning electron microscope

(SEM, ZIESS EVO 50).

In order to make the Ag nanorods surface hydrophobic,

the AgNR samples were coated by dipping the AgNR sub-

strates in a solution of 1 mM HDFT prepared in 30 ml etha-

nol for different time varying from 15 min to 60 min. After

a)Author to whom correspondence should be addressed. Electronic mail:

[email protected].

0003-6951/2014/104(2)/023107/4/$30.00 VC 2014 AIP Publishing LLC104, 023107-1

APPLIED PHYSICS LETTERS104, 023107 (2014)


On: Thu, 13 Feb 2014 15:24:52
http://dx.doi.org/10.1063/1.4861836http://dx.doi.org/10.1063/1.4861836http://dx.doi.org/10.1063/1.4861836mailto:[email protected]://crossmark.crossref.org/dialog/?doi=10.1063/1.4861836&domain=pdf&date_stamp=2014-01-14mailto:[email protected]://dx.doi.org/10.1063/1.4861836http://dx.doi.org/10.1063/1.4861836http://dx.doi.org/10.1063/1.4861836


3/5

incubation, the samples were removed from the solution,

gently rinsed with de-ionized (DI) water and dried with a

gentle nitrogen blow. To determine the static contact angle,

water droplets of 5 ll volume were deposited on AgNR sam-

ples. The images of the droplets on samples were captured

using CMOS camera equipped with a magnifying lens. The

contact angle on the Ag nanorods was measured by analyz-

ing the water droplets images with ImageJ software

(National Institute of Health, USA). The contact angle meas-urements were repeated five times at different positions of

each sample. For SEF measurements, 1 mM aqueous solution

of Rhodamine 6G (Rh6G) in DI water was prepared. The

droplet of 5 ll volume of this aqueous dye solution was de-

posited on AgNR samples and was allowed to dry in an am-

bient temperature. The fluorescence measurement was done

using ISS PC1 spectrofluorometer equipped with a 300 W

Xe arc lamp at room temperature (RT) using 511 nm excita-

tion wavelength.

GLAD is a physical vapour deposition technique where

the deposition flux is incident on a substrate with a large

vapour angle (>75) with respect to the surface normal.37

Due to the shadowing effect during growth GLAD produces

AgNR arrays inclined in the direction of vapour flux. The

SEM micrographs of AgNR samples grown at temperature at

313 K and 133 K are shown in Fig.1. It can be observed from

the SEM images that there is a drastic contrast in the surface

morphology of AgNR grown at 133 K and 313 K. The sub-

strate temperatureTssignificantly affects the morphology and

in particularly the size and lateral distribution of Ag nano-

rods. The variation in the size and distribution of AgNR were

calculated in terms of nanorod diameter and nanorod density

(nanorods/cm2). It was found that there was not much varia-

tion in nanorod density (1.3 108 nanorods/cm2 at 313 K to

1.8 108

nanorods/cm

2

at 133 K) but the nanorod diameterdecreases for the low temperature Ts 133K depositedAgNR from 172 nm to 63 nm. Another important difference

is the presence of porous nanostructures in the low tempera-

ture (LT) deposited Ag film, whereas the RT, Ts 313K, de-posited AgNR arrays appear to be solid and more rod like.

The measured contact angle h, on bare AgNR substrates was

found to be 107.16 3 and 134.862.5 for the RT and LT

AgNR substrates, respectively. The superhydrophobic metal-

lic surfaces can be obtained by coating a monolayer of low

surface energy materials like fluorinated compounds. The

AgNR samples were coated with HDFT for different time

varying from 15 min to 60 min. The water contact angle val-

ues were found to increase with the increase in the coatingtime of the HDFT molecules deposited on AgNR substrates

until a critical time was reached after which the water contact

angleh values remained almost unchanged. For example, for

the deposition time of 15 min,hreaches a value of 134.862

and 162.06 2 for RT and LT grown AgNR samples, respec-

tively. However, when the coating time was increased to

30 min, h reaches to a maximum contact angle (hmax) value

attainable on LT AgNR sample of 164.162 and that for the

RT grown AgNR sample hmax was 142.262. Further

increase in the coating time has no effect onh and it remains

almost constant as shown in Fig.2. This is the optimum coat-

ing time for AgNR with HDFT after which no significant

change in the contact angle was observed. The HDFT coating

made the Ag nanorods surface hydrophobic but change in

their surface morphology was not observed after the HDFTcoating (see supplementary material42).

Self assembled monolayers, such as HDFT, are ordered

assemblies ofmolecules that form spontaneously on surface

via adsorption.38 The HDFT surface is nonpolar and the sul-

phur head-group attached to the substrate via covalent bond-

ing promotes close-packing leading to a monolayer covering

the substrate, the tail group serves for the functionalization

purposes to control interfacial properties of the monolayer.

Dipping AgNR substrates in a solution of HDFT supplies a

monolayer of highly fluorinated hydrophobic molecules low-

ering the surface energy and apparently increasing the con-

tact angle.

According to Cassie and Baxter model, the creation ofair gaps because of the roughness can keep the droplet float-

ing thereby increasing its contact angle. The increase in con-

tact angle is given by the relationship39

cos h0 fcos h1 1; (1)

whereh0 is the observed contact angle, h is Youngs contact

angle, and f is the solid fraction on which the droplet sits.

Hence, we can see that the smaller the solid fraction larger

the apparent contact angle.

The decrease in the average nanorod diameter and pres-

ence of porosity decreases the solid fraction due to the

increase in volume of the air entrapped in between the gapsFIG. 1. SEM image of silver nanorods grown on Si substrate at (a) 313 K

and (b) 133 K.

FIG. 2. Variation of water contact angle (h)with HDFT coating time for Ag

nanorods grown at room temperature (313K) and low temperature (133 K).

023107-2 Kumaret al. Appl. Phys. Lett.104, 023107 (2014)


On: Thu, 13 Feb 2014 15:24:52


4/5

of the rough structures of LT deposited AgNR substrates.

The presence of air in place of a solid surface simply reduces

the effective surface energies responsible for spreading of

water on the surface and hence improving the hydrophobic-

ity of the considered surface. This composite structure of air

and solid combination along with the presence of low surface

energy components on the roughened surface reduces the af-

finity of water to the surface and thus increases the contact

angle. Therefore, increase in water contact angle value maybe attributed to the rough nanoscale morphological pattern

obtained on these surfaces as well as the presence of low sur-

face energy fluorinated species present on these surfaces.

The superhydrophobic (having hmax value) AgNR sam-

ples grown at 133 K were employed for further SEF studies.

Fig. 3 shows the variation in the peak intensity of fluores-

cence of Rh6G molecule deposited on HDFT coated LT

grown AgNR samples as a function of coating time. The in-

tensity of the fluorescence signal was initially amplified with

an increase in the coating time and then it decreases with the

coating time. As we have discussed that the contact angle

was also found to increase with HDFT coating time, the

increase in the peak intensity may be attributed to the

increase in the contact angle from 134 to 164. For the

enhancement factor (EF) measurements the fluorescence

spectra of Rh6G molecules on both AgNR and reference

substrates were collected. The conventional Ag thin film

grown at RT was considered as the reference substrate for

SEF measurements. The fluorescence intensity was found to

be increased on the AgNR samples. However, it can be

noticed that the fluorescence intensity was observed to be

much higher on the HDFT coated superhydrophobic AgNR

sample compared to the bare AgNR sample. The SEF

response of AgNR samples canbe understood quantitatively

by measuring the EF as follows:

40

EF IsubstrateIbackgroundIreference Ibackground

; (2)

where Isubstrate is the fluorescence intensity on AgNR sub-

strate, Ireference is the fluorescence intensity on reference

(conventional Ag thin film) substrate, and Ibackground is the

background intensity of the spectra. The calculated SEF

enhancement factors of HDFT coated superhydrophobic

AgNR and bare AgNR samples are shown in Fig. 4.

Interestingly, it can be noticed that the HDFT coated AgNR

samples offer almost 3 times greater SEF enhancement fac-

tor compared to bare AgNR samples. This observed rise inEF clearly suggests that the superhydrophobic HDFT coated

AgNR arrays makes a better and highly sensitive SEF active

substrates. This significant amplification in the SEF intensity

of Rh6G can be explained on the basis of superhydrophobic

condensation effect.31,32 When a droplet of a diluted solution

is put on a substrate which is not superhydrophobic then the

droplet will wet the surface and in turn spread out the dis-

solved fluorescent molecules over a larger area. In case of

the superhydrophobic substrate, the contact area between the

droplet and the underlying surface is highly reduced and

when the droplet is allowed to evaporate it progressively

reduces its volume and contact area during evaporation with-

out changing its quasi-spherical shape. Accordingly, the dis-

solved molecule or compound in the droplet that was

initially diluted becomes more and more concentrated and

localized after the evaporation.30,41 At the end of evapora-

tion, when the droplet reaches a condition of instability it

collapsed and the solute get deposited in a confined region

which results in the amplification of the fluorescence signal.

Hence, by using superhydrophobic surfaces the molecules

can get concentrated over a small area to carry out molecular

detection using plasmonic surface enhancement of electro-

magnetic field in the vicinity of metallic nanostructures.

In summary, we have fabricated HDFT coated superhy-

drophobic AgNR substrates for SEF application with contactangle 16462. For AgNR deposited at correspondingly

lower substrate temperature of 133 K, the nanorods were

observed to have smaller diameter of 63 nm compared to

172 nm for the RT (313 K) grown Ag nanorods. The high

contact angle of the LT deposited AgNR is a manifestation

of increase in the porosity and hence increase in the area of

FIG. 3. Variation in peak intensity with HDFT coating time. The normalized

SEF intensities of the strongest peak with different coating time of

Rhodamine 6G. The t 0 corresponds to an uncoated Ag nanorodssubstrate.

FIG. 4. EF measured on bare and HDFT coated Ag nanorod samples with

respect to a conventional Ag thin film. Both the samples were deposited at

133 K substrate temperature.



On: Thu, 13 Feb 2014 15:24:52


5/5

air entrapped in between the gaps of the nanorods because of

thinner Ag nanorods. The HDFT coated superhydrophobic

AgNR arrays exhibited 3-fold fluorescence signal enhance-

ment than the bare AgNR sample and the signal was found

to increase with increase in the contact angle. These highly

sensitive superhydrophobic SEF active AgNR arrays sub-

strates may offer a potential application such as trace analy-

sis and biosensing.

The author (S.K.) is thankful to IIT Delhi for providing

research fellowship. This research was funded by DST, India

Grant Nos. SR/S2/CMP-13/2010 and RP02395 Nanoscale

Research Facility, IIT Delhi.

1A. Scardino, R. De Nys, O. Ison, W. OConnor, and P. Steinberg,

Biofouling19(Suppl. 1), 221 (2003).2T. Kako, A. Nakajima, H. Irie, Z. Kato, K. Uematsu, T. Watanabe, and K.

Hashimoto, J. Mater. Sci. 39, 547 (2004).3

D. Quere,Rep. Prog. Phys. 68, 2495 (2005).4M. He, J. Wang, H. Li, and Y. Song,Soft Matter7, 3993 (2011).5

B. Yin, L. Fang, A. Tang, Q. Huang, J. Hu, J. Mao, G. Bai, and H. Bai,

Appl. Surf. Sci. 258, 580 (2011).6

B. Kiraly, S. Yang, and T. J. Huang, Nanotechnology24, 245704 (2013).7M. K. Dawood, H. Zheng, N. A. Kurniawan, K. C. Leong, Y. L. Foo, R.

Rajagopalan, S. A. Khan, and W. K. Choi,Soft Matter8, 3549 (2012).8

G. K. Kannarpady, R. Sharma, B. Liu, S. Trigwell, C. Ryerson, and A. S.

Biris,Appl. Surf. Sci. 256, 1679 (2010).9

D. P. Singh and J. P. Singh,Appl. Phys. Lett. 102, 243112 (2013).10K. Robbie, M. J. Brett, and A. Lakhtakia,Nature 384, 616 (1996).11

Y.-P. Zhao, D.-X. Ye, G.-C. Wang, and T.-M. Lu, Nano Lett. 2, 351

(2002).12

C. M. Zhou and D. Gall, J. Vac. Sci. Technol., A 25, 312 (2007).13

D. P. Singh, P. Goel, and J. P. Singh,J. Appl. Phys. 112, 104324 (2012).14

M. Suzuki,J. Nanophotonics7, 073598 (2013).15

H. G. Moon, Y.-S. Shim, D. H. Kim, H. Y. Jeong, M. Jeong, J. Y. Jung, S.

M. Han, J. K. Kim, J.-S. Kim, H.-H. Park, J.-H. Lee, H. L. Tuller, S.-J.

Yoon, and H. W. Jang,Sci. Rep. 2, 588 (2012).16C. Li, Z. Wang, P.-I. Wang, Y. Peles, N. Koratkar, and G. P. Peterson,

Small4, 1084 (2008).17A. G. Mark, J. G. Gibbs, T.-C. Lee, and P. Fischer, Nat. Mater. 12, 802

(2013).18

S. Shanmukh, L. Jones, J. Driskell, Y. Zhao, R. Dluhy, and R. A. Tripp,

Nano Lett. 6, 2630 (2006).

19J. P. Singh, T. E. Lanier, H. Zhu, W. M. Dennis, R. A. Tripp, and Y. Zhao,

J. Phys. Chem. C 116, 20550 (2012).20J. G. Gibbs, A. G. Mark, S. Eslami, and P. Fischer, Appl. Phys. Lett. 103,

213101 (2013).21Y.-J. Liu, H. Y. Chu, and Y.-P. Zhao, J. Phys. Chem. C 114, 8176 (2010).22I. Abdulhalim, A. Karabchevsky, C. Patzig, B. Rauschenbach, B.

Fuhrmann, E. Eltzov, R. Marks, J. Xu, F. Zhang, and A. Lakhtakia, Appl.

Phys. Lett. 94, 063106 (2009).23

R. Aroca, Surface-Enhanced Vibrational Spectroscopy (Google eBook)

(John Wiley & Sons, 2006), p. 260.24

M. Moskovits,Rev. Mod. Phys.57, 783 (1985).25C. D. Geddes, A. Parfenov, D. Roll, I. Gryczynski, J. Malicka, and J. R.

Lakowicz, Spectrochim. Acta, Part A60, 1977 (2004).26

C. D. Geddes, A. Parfenov, and J. R. Lakowicz, Appl. Spectrosc. 57, 526

(2003).27

A. Parfenov, I. Gryczynski, J. Malicka, C. D. Geddes, and J. R. Lakowicz,

J. Phys. Chem. B 107, 8829 (2003).28

M. K. Hossain, G. G. Huang, T. Kaneko, and Y. Ozaki, Phys. Chem.

Chem. Phys. 11, 7484 (2009).29

J. P. Singh, H. Chu, J. Abell, R. A. Tripp, and Y. Zhao, Nanoscale 4, 3410

(2012).30F. Gentile, G. Das, M. L. Coluccio, F. Mecarini, A. Accardo, L. Tirinato,

R. Tallerico, G. Cojoc, C. Liberale, P. Candeloro, P. Decuzzi, F. De

Angelis, and E. Di Fabrizio,Microelectron. Eng. 87, 798 (2010).31

J.-P. Coppe, Z. Xu, Y. Chen, and G. L. Liu, Nanotechnology 22, 245710

(2011).32

F. Xu, Y. Zhang, Y. Sun, Y. Shi, Z. Wen, and Z. Li, J. Phys. Chem. C 115,9977 (2011).

33T. Karabacak, G.-C. Wang, and T.-M. Lu, J. Vac. Sci. Technol., A 22,

1778 (2004).34

J. P. Singh, T. Karabacak, D.-X. Ye, D.-L. Liu, C. Picu, T.-M. Lu, and G.-

C. Wang,J. Vac. Sci. Technol., B: Microelectron. Nanometer Struct. 23,

2114 (2005).35

C. Khare, C. Patzig, J. W. Gerlach, B. Rauschenbach, and B. Fuhrmann,

J. Vac. Sci. Technol., A 28, 1002 (2010).36

D. P. Singh and J. P. Singh,J. Phys. Chem. C 115, 11914 (2011).37

Y. Zhao, D. Ye, G. Wang, and T. Lu, Proc. SPIE 5219, 59 (2003).38

F. Schreiber,Prog. Surf. Sci. 65, 151 (2000).39

A. B. D. Cassie and S. Baxter, Trans. Faraday Soc. 40, 546 (1944).40

J. Dong, H. Zheng, X. Yan, Y. Sun, and Z. Zhang, Appl. Phys. Lett. 100,

051112 (2012).41F. D. Angelis, F. Gentile, F. Mecarini, G. Das, M. Moretti, P. Candeloro,

M. L. Coluccio, G. Cojoc, A. Accardo, C. Liberale, R. P. Zaccaria, G.Perozziello, L. Tirinato, A. Toma, G. Cuda, R. Cingolani, E. D. Fabrizio,

F. D. Angelis, and E. D. Fabrizio,Nat. Photonics 5, 682 (2011).42

See supplementary material at http://dx.doi.org/10.1063/1.4861836 for

SEM images of bare and HDFT coated Ag nanorods.



On: Thu 13 Feb 2014 15:24:52
http://dx.doi.org/10.1080/0892701021000057882http://dx.doi.org/10.1023/B:JMSC.0000011510.92644.3fhttp://dx.doi.org/10.1088/0034-4885/68/11/R01http://dx.doi.org/10.1039/c0sm01504khttp://dx.doi.org/10.1016/j.apsusc.2011.08.063http://dx.doi.org/10.1088/0957-4484/24/24/245704http://dx.doi.org/10.1039/c2sm07279chttp://dx.doi.org/10.1016/j.apsusc.2009.09.093http://dx.doi.org/10.1063/1.4811751http://dx.doi.org/10.1038/384616a0http://dx.doi.org/10.1021/nl0157041http://dx.doi.org/10.1116/1.2539328http://dx.doi.org/10.1063/1.4767634http://dx.doi.org/10.1117/1.JNP.7.073598http://dx.doi.org/10.1038/srep00588http://dx.doi.org/10.1002/smll.200700991http://dx.doi.org/10.1038/nmat3685http://dx.doi.org/10.1021/nl061666fhttp://dx.doi.org/10.1021/jp305061shttp://dx.doi.org/10.1063/1.4829740http://dx.doi.org/10.1021/jp1001644http://dx.doi.org/10.1063/1.3081031http://dx.doi.org/10.1063/1.3081031http://dx.doi.org/10.1103/RevModPhys.57.783http://dx.doi.org/10.1016/j.saa.2003.10.014http://dx.doi.org/10.1366/000370203321666542http://dx.doi.org/10.1021/jp022660rhttp://dx.doi.org/10.1039/b903819chttp://dx.doi.org/10.1039/b903819chttp://dx.doi.org/10.1039/c2nr00020bhttp://dx.doi.org/10.1016/j.mee.2009.11.083http://dx.doi.org/10.1088/0957-4484/22/24/245710http://dx.doi.org/10.1021/jp201897jhttp://dx.doi.org/10.1116/1.1743178http://dx.doi.org/10.1116/1.2052747http://dx.doi.org/10.1116/1.3447231http://dx.doi.org/10.1021/jp200819mhttp://dx.doi.org/10.1117/12.505253http://dx.doi.org/10.1016/S0079-6816(00)00024-1http://dx.doi.org/10.1039/tf9444000546http://dx.doi.org/10.1063/1.3681420http://dx.doi.org/10.1038/nphoton.2011.222http://dx.doi.org/10.1063/1.4861836http://dx.doi.org/10.1063/1.4861836http://dx.doi.org/10.1038/nphoton.2011.222http://dx.doi.org/10.1063/1.3681420http://dx.doi.org/10.1039/tf9444000546http://dx.doi.org/10.1016/S0079-6816(00)00024-1http://dx.doi.org/10.1117/12.505253http://dx.doi.org/10.1021/jp200819mhttp://dx.doi.org/10.1116/1.3447231http://dx.doi.org/10.1116/1.2052747http://dx.doi.org/10.1116/1.1743178http://dx.doi.org/10.1021/jp201897jhttp://dx.doi.org/10.1088/0957-4484/22/24/245710http://dx.doi.org/10.1016/j.mee.2009.11.083http://dx.doi.org/10.1039/c2nr00020bhttp://dx.doi.org/10.1039/b903819chttp://dx.doi.org/10.1039/b903819chttp://dx.doi.org/10.1021/jp022660rhttp://dx.doi.org/10.1366/000370203321666542http://dx.doi.org/10.1016/j.saa.2003.10.014http://dx.doi.org/10.1103/RevModPhys.57.783http://dx.doi.org/10.1063/1.3081031http://dx.doi.org/10.1063/1.3081031http://dx.doi.org/10.1021/jp1001644http://dx.doi.org/10.1063/1.4829740http://dx.doi.org/10.1021/jp305061shttp://dx.doi.org/10.1021/nl061666fhttp://dx.doi.org/10.1038/nmat3685http://dx.doi.org/10.1002/smll.200700991http://dx.doi.org/10.1038/srep00588http://dx.doi.org/10.1117/1.JNP.7.073598http://dx.doi.org/10.1063/1.4767634http://dx.doi.org/10.1116/1.2539328http://dx.doi.org/10.1021/nl0157041http://dx.doi.org/10.1038/384616a0http://dx.doi.org/10.1063/1.4811751http://dx.doi.org/10.1016/j.apsusc.2009.09.093http://dx.doi.org/10.1039/c2sm07279chttp://dx.doi.org/10.1088/0957-4484/24/24/245704http://dx.doi.org/10.1016/j.apsusc.2011.08.063http://dx.doi.org/10.1039/c0sm01504khttp://dx.doi.org/10.1088/0034-4885/68/11/R01http://dx.doi.org/10.1023/B:JMSC.0000011510.92644.3fhttp://dx.doi.org/10.1080/0892701021000057882

delayed freezing of water droplet on silver nanocolumnar film

Documents