Fast Electrically Switchable Capillary Effects

Abstract

Through the application of a potential between a water droplet on a hydrophobic coating and the underlying conductive substrate, we have shown control over the contact angle of the droplet. The same phenomenon can be used to control capillary rise of a liquid in a coated capillary over several centimeters in a short time. Interesting applications such as a temporary improvement of adhesion (drying of paint), electrical control of liquid lenses, and patternwise and dynamic filling of a capillary array are in sight.