Temperature-dependent wettability on a titanium dioxide surface

Controlling surface wettability, expressed in terms of contact angle, is a significant issue in nanotechnology. In this paper, through extensive molecular dynamics simulations, we show that the contact angle of water droplet on a TiO2 surface is considerably influenced by the temperature variations, i.e. as the temperature increases, the contact angle decreases and the surface becomes more hydrophilic. We address the issue of accurate force fields and determine the partial charges that can closely reproduce the experimental contact angle. Detailed understanding of the temperature-dependent variation of contact angle is developed by hydrogen bonding analysis.