The electrowetting effect has been defined as “the change in solid-electrolyte contact angle due to an applied potential difference between the solid and the electrolyte”. The phenomenon of electrowetting can be understood in terms of the forces that result from the applied electric field. It is also known that the contact angle supression or saturation phenomenum through voltage can be affected by changing the detailed geometry of the system. It is predicted that in reversed electrowetting, the contact angle can possibly grow with the voltage.
Electrowetting is now used in a wide range of applications from modular to adjustable lenses, electronic displays (e-paper) as well as switches for optical fibers. Electrowetting has recently been evoked for manipulating Soft Matter. Furthermore, filters with electrowetting functionality has been suggested for cleaning oil spills and separating oil-water mixtures. By optically modulating the number of carriers in space-charge region of the semiconductor, the contact angle of a liquid droplet can be altered in a continuous way. This is called photoelectricalwetting and it can be observed if the conductor in the liquid/insulator/conductor stack used for electrowetting is replaced by a semionductor.