Preparation and properties of a long time durable superhydrophilic titanium dioxide film obtained by a sol-gel process

Abstract The superhydrophilic phenomenon of titanium dioxide (TiO2) has some potential applications. However, the superhydrophilicity can be obtained only using ultraviolet (UV) light irradiation and cannot be regained conveniently due to the energy band gap of TiO2. In this study, superhydrophilic TiO2 film on a glass substrate was prepared by a simple sol-gel method and the sol was doped with nitrogen, fluorine and polyethylene glycol (PEG). The preparation method was discussed and the film was characterized. Results show that the anatase TiO2 was obtained at about 500 °C, and the redshift of nitrogen-doped film was the largest, whereas the transmittance of fluorine-doped film was increased. The sizes of TiO2 particles in the films are uniform and the films are homogeneous except PEG-doped TiO2. Superhydrophilicity of films doped with PEG can maintain 12 days and can be regained by the irradiation of sunlight.