Preparation and property of super-hydrophilic SiO2-TiO2 nano-particle layer

Abstract

TiO2 particle single layer and SiO2-TiO2 particle double layers on glass substrate are obtained by self-assembly technique. For SiO2-TiO2 particle double layers, SiO2 Particle layer is made by spin-coating with SiO2 particles closely packed,while TiO2 Particle layer is obtained through layer-by-layer method in both cases of TiO2 particle single layer and SiO2-TiO2 particle double layers, with TiO2 particles non- closely packed. The theoretical roughness of TiO2 particle single layer and SiO2-TiO2 particle double layers are analyzed. Microstructures of these two coatings are studied with scanning electron microscope. Water contact angles before and after exposure to UV light are measured by drop meter separately. Light catalytic ability of organics degradation is determined by spectrophotometer. The experimental results show that the water contact angles of the as-prepared particle films increase if these coatings are stored in dark for days till the contacts become stable, while if exposed to UV light, they become super-hydrophilic with contact angles approaching 0°,that the roughness greatly affects water contact angle, and that the catalytic ability of SiO2-TiO2 particle double layers is superior to TiO2 particle single layer.