Electrowetting

With electrowetting (English electrowetting ) is referred to the physical phenomenon in which an electric field by varying the surface tension of a liquid ( electrocapillarity ) means that the liquid wets a Subject stronger. Gabriel Lippmann 1875 provided the physical explanation.

Building a electrowetting cell

Basically, a electrowetting cell always is a kind of capacitor in which the space between the electrodes is filled with a hydrophobic liquid (e.g. oil ) and water, wherein one of the electrodes is hydrophobically coated. Without the oil field specifies a film over the coated electrode, with the field displaces the water the oil film, since the adjacent field cancels the polarization of the dipoles in the water surface.

Contact angle of the liquid

The contact angle decreases with increasing voltage U between the liquid droplet and the electrode below the supporting surface according to the Lippmann equation:

Areas of application

Can be realized, different electro-optic devices of the embodiment of the liquid space, the electrodes and the color of the oil:

• Color displays
• Liquid lenses with adjustable focal length
• Iris

Electrowetting can stabilize in the microfluidic liquid surfaces which are otherwise unstable due to capillary forces to the bearing surface.