Control of Surface Wettabilty by Light lllumination: Surface Wettability Control Utilizing Photo-induced Surface Reaction of Titanium Dioxide

Abstract

We report photo-generation of highly hydrophilic surface of titanium dioxide. The photo-induced hydrophilicizing is achieved by photo-generation of Ti⁴⁺ to Ti³⁺ at definite sites on the surface, resulting in preferential adsorption of hydroxyl groups on corresponding oxygen vacant sites. We also report the photo-generation of titanium dioxide amphiphilic surface on definite photo illumination condition. The unique character of this surface is ascribed to the microstructure of hydrophilic and oreophilic domain. The hydrophilic or amphiphilic titanium dioxide coating can be applied for antifogging mirror or glass and also self-cleaning paint for various industrial materials. Several commercial applications including antifogging automobile side-view mirror or self-cleaning exterior ceramic tile has been starting to hit the market.