wetting of a substrate controlled by the voltage between a droplet and the substrate covered with a dielectric film.(IEC/2015)
The contact angle of a liquid droplet, typically an electrolyte, on a substrate can be electrically controlled because the solid-liquid surface interfacial tension can be controlled with the energy stored in the electric double layer which works as capacitor. Covering the electrode with a dielectric material of determined thickness, the capacitance can be determined with ease. Electro wetting on dielectric is used typically in microfluidic devices.