Influence of pH value of TiO₂ sol on surface gloss of corresponding TiO₂ film coated on ceramic tiles

Abstract

A series of TiO 2 sols with different pH values prepared by the sol-gel method under acid conditions were coated onto the surfaces of ceramic tiles to obtain the corresponding TiO 2 films respectively. The surface gloss and roughness of the as-prepared TiO 2 films were measured by a glossmeter and an atomic force microscope (AFM) respectively. It has been found that the surface gloss of the as-prepared TiO 2 films is decreased but its roughness is increased with the increase of the pH value of TiO 2 sol. Moreover, the measurement result of the as-prepared TiO 2 sols by Zetasizer shows that the ζ potential of TiO 2 sol is increased with the increase of pH value of TiO 2 sol. It is proposed that the increase of ζ potential will cause a stronger repulsion of particles in TiO 2 sol, resulting in a rougher surface and then lower surface gloss of the corresponding TiO 2 film.