Electrowetting Properties of ZnO and TiO2 Nanostructured Thin Films

Electrowetting experiments have been performed on ZnO and TiO2 nanostructured thin films grown on crystalline Si and subsequently coated by a thin dielectric layer. The contact angle is decreased upon the application of an electric field between the film and a water droplet placed on the dielectric surface until saturation is observed. The electrowetting phenomenon is reversible, with the droplet returning to its initial hydrophobic state, when the applied potential is decreased. For the actuation of the droplet, low voltage, on the order of a few volts, is required.