Preparation of TiO2-coated ZnO Nanoparticles and Their Effect on the UV Absorption of a Poly(vinyl alcohol) Composite Film

Titanium oxide (TiO2) and zinc oxide (ZnO) composite structured nanoparticles were prepared by combining a sol-gel process and a solvothermal method. Titanium (IV) isoproxide (TTIP), used as a TiO2 precursor, was dissolved in a colloidal ZnO nanoparticle solution synthesized by the sol-gel method, and TiO2 was synthesized via solvothermal synthesis onto the ZnO nanoparticles. The effects of reaction conditions such as pH, reaction temperature, and reaction time on the morphology of the composite nanoparticles and the ultraviolet (UV) absorbance of their polymer composite films were investigated. The UV absorption of the poly(vinyl alcohol) (PVA) composite film with TiO2-coated ZnO nanoparticles was higher than that of the TiO2, ZnO, and ZnO-coated TiO2 composite films. The reaction pH was found to have the strongest influence on the UV absorbance of the PVA/(TiO2/ZnO) composite film. A pH of 7.0, reaction temperature of 250 °C, and reaction time of 24 h were the optimum conditions for UV absorption.