Electrostatic actuation of liquid droplets for micro-reactor applications

A device for the electrostatic actuation of liquid droplets on a solid surface is developed. Arrays of electrodes are micro-fabricated on a substrate, which is covered by a hydrophobic layer. Wafer droplets, typically μl in volume, takes a spherical shape on the surface, and are actuated dielectrophoretically by switching the voltage applied to the electrode array. Transportation of droplets, deflecting a droplet in either of the bifurcating paths, and the mixing of two droplets by collision are experimentally demonstrated. The device can be used for a micro chemical reactor where transport, sorting and mixing of reagents constitute basic unit-operations