Electrowetting Effect: Theory, Modeling, and Applications

Abstract

Electrowetting is a phenomenon in which an electric field at a fluid interface changes the equilibrium interface position. This is generally observed as a quadratic relationship between the applied voltage and the change in the cosine of the apparent contact angle. While the phenomena were first observed more than 100 years ago, until recently, applications were limited by poor reliability. The application of modern materials and manufacturing methods has enabled the fabrication of a wide range of devices that show excellent repeatability. Applications range from focusing lenses to miniature biomedical diagnostics and optical displays. The article reviews the basic electrowetting phenomena, the characteristics of key configurations, and key materials issues in fabricating reliable electrowetting devices. Some practical applications and modeling approaches of the electrowetting phenomena are also reviewed.