Photocatalytic and Superhydrophilic TiO2-SiO2 Coatings on Marble for Self-Cleaning Applications

Abstract

The application of photocatalytic and self-cleaning titanium dioxide (TiO2) nanomaterials coating on the stone of architectural heritage (particularly on marble) can be used to preserve their aesthetic qualities. The present work describes the effect of dipping time on the wetting property of coatings and the effect of UV irradiation on the coating in terms of hydrophilicity. The suspension of TiO2-SiO2 is prepared by adding 30–50 nm in size TiO2 particles in the sol–gel processed SiO2 solution. The water contact angle (WCA) decreases with increasing dipping time of piece of marble in TiO2 – SiO2 suspension. Also the hydrophilicity of coating increases with increasing UV illumination time. The 2D and 3D laser microscope analysis revealed surface structure and stable surface roughness of 1.0 µm. Such type of superhydrophilic TiO2 – SiO2 coating may be used to protect architectural heritage and buildings.