Whiter, Brighter, and More Stable Cellulose Paper Coated with TiO2/SiO2 Core/Shell Nanoparticles using a Layer-by-Layer Approach



To inhibit the photocatalytic degradation of organic material supports induced by small titania (TiO2) nanoparticles, four kinds of TiO2 nanoparticles, that is, commercial P25-TiO2, commercial rutile phase TiO2, rutile TiO2 nanorods and rutile TiO2 spheres, prepared from TiCl4, were coated with a thin, but dense, coating of silica (SiO2) using a conventional sol–gel technique to form TiO2/SiO2 core/shell nanoparticles. These core/shell particles were deposited and fixed as a very thin coating onto the surface of cellulose paper samples by a wet-chemistry polyelectrolyte layer-by-layer approach. The TiO2/SiO2 nanocoated paper samples exhibit higher whiteness and brightness and greater stability to UV-bleaching than comparable samples of blank paper. There are many potential applications for this green chemistry approach to protect cellulosic fibres from UV-bleaching in sunlight and to improve their whiteness and brightness.