Targeted Functionalization of Nanoparticle Thin Films via Capillary Condensation

Abstract
Capillary condensation, an often undesired natural phenomenon in nanoporous materials, was used advantageously as a universal functionalization strategy in nanoparticle thin films assembled layer-by-layer. Judicious choice of nanoparticle (and therefore pore) size allowed targeted capillary condensation of chemical vapors of both hydrophilic and hydrophobic molecules across film thickness. Heterostructured thin films with modulated refractive index profiles produced in this manner exhibited broadband antireflection properties with an average reflectance over the visible region of the spectrum of only 0.4%. Capillary condensation was also used to modify surface chemistry and surface energy. Photosensitive capillary-condensates were UV-cross-linked in situ. Undesired adventitious condensation of humidity could be avoided by condensation of hydrophobic materials such as poly(dimethyl siloxane). © 2009 American Chemical Society.

Citation
Gemici Z, Schwachulla PI, Williamson EH, Rubner MF, Cohen RE (2009) Targeted Functionalization of Nanoparticle Thin Films via Capillary Condensation. Nano Lett 9: 1064–1070. Available: http://dx.doi.org/10.1021/nl803435s.

Acknowledgements
We thank Professor Francesco Stellacci and Professor Gareth McKinley at MIT for useful discussions; the MIT MRSEC program of the National Science Foundation (Grant DMR 03-13282), Essilor International SA for funding; and the Center for Materials Science and Engineering (CMSE) and the Institute for Soldier Nanotechnologics (ISN) for access to shared equipment facilities. Z.G. thanks KAUST for fellowship support (beginning 06/2008).

Publisher
American Chemical Society (ACS)

Journal
Nano Letters

DOI
10.1021/nl803435s

PubMed ID
19220006

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