Photogeneration of Highly Amphiphilic TiO2 Surfaces

The photoconvertible surface wettability of TiO2 materials—UV illumination of these materials can generate surfaces that display a 0° contact angle for both water and oily liquids—is investigated. Frictional force, X-ray photoelectron, and Fourier transform infrared spectroscopies are used to supply information at a microscopic level. It is concluded that UV illumination is able to convert initially hydrophobic TiO2 surfaces into highly amphiphilic ones. This behavior is ascribed to photogenerated Ti3+ defect sites that favor dissociative water adsorption.