Abstract: Ag nanoparticle-PVA composite systems were prepared by three methods. In the heating-induced reduction, Ag nanoparticles formed had a diameter of 15 nm, and showed a broad surface plasmon resonance absorption band at λ_max 420 nm. In the ambient reduction by NaBH₄, the surface plasmon resonance absorption of Ag nanoparticles blue-shifted to 409 nm, and became narrower. The average diameter of Ag nanoparticles produced was 8.7 nm. When the reduction process was carried out at low temperature (0 ℃), the absorption of Ag nanoparticles further blue-shifted to 397 nm, and 3.5 nm Ag nanoparticles were obtained. Smooth, transparent and uniform thin films were fabricated by spin-coating the Ag nanoparticle-PVA composite systems on substrates. This approach is suited for preparation of uniform multilayer films of varied thicknesses and spectroscopic properties. When Ag-PVA composite system and Ti(O_nBu)₄ ethanolic solution were alternatively spin-coated on substrate, Ag-PVA/TiO₂ composite films were obtained. UV-Visible spectra showed a regular film growth and enhancement of film absorption with increasing the number of Ag-PVA layers. In contrast, no significant effect of TiO₂ layers was observed on the absorption spectrum of film. Such organic/inorganic nanostructured multilayer films may be promising in optical, electronic, and catalytic applications.

Key words: silver nanoparticle, polymer thin film, organic/inorganic composite thin film