Demonstration of Four Fundamental Operations of Liquid Droplets for Digital Microfluidic Systems Based on anElectrowetting-on-Dielectric Actuator

An electrowetting-on-dielectric actuator is developed, in which the liquid is sandwiched between top and bottom plates. For the bottom plate, silicon wafer is used as the substrate, the heavily phosphorus-doped polysilicon film is deposited by low pressure chemical vapour deposition as the microelectrode array, and thermally grown SiO₂ film as the dielectric layer. The top plate is a glass plate covered with transparent and conductive indium tin oxide as the ground electrode. In addition, a Teflon^R AF1600 film is spun on the surface of both the plates as the hydrophobic layer. The experimental results show that when the gap height between two plates is 133μm, a prototype of the device is capable of creating, transporting, merging and dividing droplets of deionized water in an
air environment with a 70V at 10Hz voltage pulse. This is also established by simulations using the computational fluidic software of CFD-ACE+.