Force characterization of dielectrophoresis in droplet transport.

Transporting microdroplets using electric fields can be accomplished with several mechanisms, the primary methods being dielectrophoresis (DEP) for electrically insulating liquids, and electrowetting on dielectric for conducting fluids. In both cases, an electric field is applied near the leading edge of the droplet using patterned electrodes, giving rise to an electrostatic pressure that induces droplet transport. This paper examines the nature of the force distribution for DEP-actuated droplets in several electrode configurations, calculated using a numerical method designed for handling jump conditions in the Poisson equation. The numerical method is described and verified by comparison with known analytical results. The net force acting upon a DEP droplet is investigated, with the effect of electrode configuration presented for several cases, demonstrating some beneficial aspects for engineering applications.