Electrowetting on Dielectrics (EWOD): Reducing Voltage Requirements for Microfluidics

INTRODUCTION Surface tension is an inherently dominant force in the microscale. Electrocapillarity, the modification of surface tension by applying an electric field, has received renewed attention because of its potential usefulness in microfluidics. Pollack et al. demonstrated a microactuator for rapid manipulation of discrete microdroplets by direct electric control of the surface tension. [1] Berge and Peseux demonstrated the use of electrocapillarity in order to change the contact angle of a transparent drop, creating a lens of variable focal length. [2] Prins et al. showed the control of fluid motion by electrocapillary pressure in three-dimensional structures containing thousands of microchannels. [3] Electrowetting was first demonstrated by Berge. [4] The general experiment scheme for electrowetting on dielectrics (EWOD) is shown in Figure 1.