Relation between motion of water droplets and dielectric property of silicone rubber under AC high-field application

The relation between motion of water droplets and their dielectric property on a silicone rubber surface is studied under AC high-field application. Both water droplets and inter-digital stainless steel electrodes are put on the silicone rubber surface and AC high field with superposition of DC offset voltage is applied to the electrodes. The vibration of water droplets, which is related to the hydrophobicity of the silicone rubber surface, is evaluated by both the image data analysis of the shape of water droplets and its dielectric measurement using unbalanced operation method of a capacitance bridge. These data are useful to determine the small changes of hydrophobicity classes with combine the usual contact angle and STRI methods.