Preparation and characterization of polymer thin films containing silver and silver sulfide nanoparticles

Composite thin films consisting of nano-sized Ag particles dispersed in nylon 11 thin films have been prepared by using a thermal relaxation technique. The films obtained were characterized by transmission electron microscopy (TEM), electron diffraction (ED), energy-dispersive X-ray (EDX) microanalysis, and optical absorption spectroscopy. The Ag nanoparticles with 4.5-9.1 nm in diameter were found to be isolated individually and dispersed uniformly in the nylon 11 matrix. The volume fraction and the mean size of Ag nanoparticles in the film could be controlled by varying the initial amount of Ag deposition. Optical absorption peak due to the surface plasmon resonance of the Ag particles were observed around 430 nm and shifted to a longer wavelength with increasing the mean size of Ag nanoparticles, and absorbance increased simultaneously. We have also prepared Ag2S nanoparticles with 4.7-11.2 nm in diameter in nylon 11 films from exposing the Ag/nylon 11 films to H2S/O-2 mixed gas. ED patterns of the particles formed after the reaction with H2S were completely indexed as those of beta-Ag2S with a monoclinic structure. The onset of the optical absorption spectra is similar to that of bulk beta-Ag2S, suggesting that Ag2S nanoparticles with diameter of ca. 5nm preserve the band structure of bulk Ag2S. (C) 2000 Elsevier Science S.A. All rights reserved.