A prototype window glass having two functions of self-cleaning and photocatalytic degradation is fabricated by coating a TiO2 thin film on one side and silica nanostructures on the other side of a glass substrate. First, a TiO2 thin film of submicron thickness is coated on one side of a clean glass substrate by immersing in an alcoholic solution of TiO2 precursor. After TiO2 film formation, the glass slide is then dipped in an alcoholic solution of silica precursor to coat silica nanostructures on the other side by a sol-gel reaction. During the fabrication process, UV-curable adhesive films are properly attached on the virgin side and the TiO2 side in turn for protection purpose. The self-cleaning function of the glass substrate is characterized by measuring contact angle and water cleaning power on the silica side, and its photocatalytic depollution function is characterized by estimating decomposition rate of dye molecules on the TiO2 side in an aqueous solution under UV irradiation. As results, the fabricated coatings are found to have characteristics of self-cleaning close to superhydrophobic surface and good photocatalytic depollution.

Keywords: Silica nanostructures, Titania thin film, Sol-gel reaction, Self-cleaning, Photocatalytic depollution.