Layer-by-layer assembled TiO2 films with high ultraviolet light-shielding property

Ultraviolet (UV) B is hazardous to human, plants and animals. With the rapid growth of ozone holes over the earth, the exploration of optical materials that can cut off harmful UV radiation is important. In this work, fusiform TiO2 nanoparticles were synthesized by a hydrothermal synthesis method. The thin films assembled with TiO2 nanoparticles and oppositely charged polyelectrolytes were fabricated via a layer-by-layer assembly method. The fabrication of poly(ethylene imine) (PEI)/TiO2 multilayer films was verified by ultraviolet-visible spectra measurements, scanning electron microscopy and atomic force microscopy. The as-prepared PEI/TiO2 multilayer films can effectively absorb harmful UVB light and filter off visible light. Most importantly, the PEI/TiO2 films can be deposited directly on various kinds of hydrophilic substrates such as quartz, glass, silicon and hydrophobic substrates such as polystyrene, polypropylene, polyethylene and polymethyl methacrylate when the hydrophilic substrates were modified to obtain a hydrophilic surface. (C) 2014 Elsevier B.V. All rights reserved.