Effect of micropillar electrode spacing on the performance of electrohydrodynamic micropumps

Electrohydrodynamic (EHD) micropumps with three-dimensional 50 μm × 50 μm micropillar electrodes were fabricated and tested in this study. Two basic electrode configurations were investigated: (i) micropillar emitter and collector electrodes (symmetric) and (ii) micropillar emitter and planar collector electrodes (asymmetric). The micropumps were fabricated by integrating chromium/gold planar electrodes with electroplated 3-D Nickel micropillars on a glass substrate with a 100 μm high PDMS microchannel. The effect of the spanwise micropillar spacing on the pump performance was determined. The pumps were tested using HFE-7100 as the working fluid for the maximum pressure generation under a no flow condition. The micropumps with the asymmetric electrode design generated a significantly higher pressure head than the corresponding micropumps with symmetric electrode configuration for the same applied voltage, with lower power consumption. A decrease in the spanwise spacing of the micropillar electrodes increased the pump performance for the symmetric configuration, while the performance decreased for the asymmetric configuration.