Fabrication and characterization of electrokinetic micro pumps

Electrokinetic (EK) micropumps have been fabricated and demonstrated in which electroosmotic flow is used to transport fluids. Deionized water and pure acetonitrile have been used as working fluids to achieve low current density pumping conditions. These EK pumps have no moving parts and can generate maximum pressures of more than 20 atm at 2 kV applied voltage. Minimizing and controlling electrolytic gas generation is a major concern. Gas generated at the downstream electrode surfaces appears to be forced to dissolve into surrounding fluid at high pressure (>7 atm) condition, and this permits a stable pump operation. Measurements of flow rate have been used to estimate pump structure parameters.