Enhanced Photochromism Of Heteropolyacid/Polyvinylpyrolidone Composite Film By Tio2 Doping

Novel composite film was synthesized by TiO2 doping into phosphomolybdic acid (PMoA)/polyvinylpyrrolidone (PVP) system. The influence of TiO2 doping on its microstructure and photochromic properties was investigated via atomic force microscopy, transmission electron microscope, Fourier transform infrared spectroscopy (FT-IR), ultraviolet-visible spectra, and X-ray photoelectron spectroscopy (XPS). After TiO2 doping, the surface of TiO2/PMoA/PVP composite film changed to rough from smooth, and the particle size significantly increased. The FT-IR results verified that the basic structure of PMoA and PVP were not destroyed in the composite films. The non-bonded interaction between the acid and polymer was strengthened by TiO2 doping. Irradiated with UV light, composite films changed from colorless to blue. The TiO2/PMoA/PVP composite film exhibited a strong photochromic effect and faster bleaching reaction than that of PMoA/PVP film. XPS results indicated that the amount of PMoA in photo-reductive reaction was increased after TiO2 doping, which resulted in the photochromic efficiencies enhanced. (C) 2014 Wiley Periodicals, Inc.