2014 Volume 122 Issue 1426 Pages 513-516
We investigated the self-cleaning efficiencies of titanium dioxide (TiO2) surface under ultraviolet (UV) irradiation in combination with a water flow (UV/water) condition using oleic acid as the model surface contaminant. UV light intensities were varied from a typical indoor intensity level to a representative outdoor intensity level in Japan. The combined UV/water treatment exhibited a much higher self-cleaning efficiency than either condition alone. This suggests that the self-cleaning effect occurred at nanometer-sized photo-induced superhydrophilic domains of the TiO2 film surface located at the interface of the TiO2 surface, oleic acid, and air.