Structural changes in RSiO3/2-TiO2 hybrid films with UV irradiation and their photocatalytic micropatterning

Abstract

UV light irradiation induced structural changes of the cleavage of silicon-carbon bonds and elimination of organic groups in organosilsesquioxane- titania (RSiO3/2-TiO2, R = methyl, ethyl, phenyl and benzyl) hybrid films due to the photocatalytic effect of TiO2 component. Phenyl and benzyl groups tended to remain in the films after the cleavage of Si-C bonds presumably due to their higher stability of aromatic rings and lager steric effect. The refractive index and dynamic hardness of all the hybrid films increased, and the thickness and contact angle for water decreased by the structural changes induced by the UV light irradiation. On the basis of these changes in film properties, micropatterning was successfully performed on the RSiO3/2-TiO2 hybrid films by UV light irradiation through a photomask. The micropatterns thus obtained should be applicable to a printing plate using the surface energy differences as well as a micro-optical component using the surface profiles and refractive index changes.