Microfabricated EHD Pumps With High Aspect Ratio Electrodes

This work presents the design, fabrication and testing of electrohydrodynamic (EHD) micropumps with three dimensional (3-D) electrodes. It is known that the body force on the fluid due to an electric field is increased by increased injection of charges. In this design, 3-D micro pillars are used electrodes to provide high electrode-fluid contact area and to improve charge injection. Three different electrode designs were used to investigate the effect of different parameters, such as electrode spacing and pillars size, on the pump performance. The electrodes were fabricated using nickel, and were integrated into a microchannel of dimensions 22mm × 5mm × 100μm. The micropumps were tested under a no-flow condition with ethanol as the working fluid. The preliminary results suggest that the new 3-D electrodes improve pump performance over pumps with 2-D planar electrodes. A maximum pressure head of 780 Pa was achieved at an applied voltage of 150 V with the 3-D electrodes.