Localized, low-voltage electro-osmotic pumping across nanoporous membranes

Abstract

This work demonstrates the principle of localized, low-voltage, continuous current electro-osmotic pumping across thin membranes. Localization of the pumping effect is obtained by employing ring electrodes, microfabricated on each side of nanoporous alumina membranes. Low voltage actuation is achieved by having the separation of the two electrodes in the microscale range—the thickness of the membrane. The measured electro-osmotic velocity increases linearly from 40μm∕s at 5V to 200μm∕s at 20V. Experimental results compare well with predictions of an electro-osmotic flow model considering the nonuniform distribution of the electric field between the electrodes.