A low-voltage nano-porous electroosmotic pump

A low-voltage electroosmotic (EO) micropump based on an anodic aluminum oxide (AAO) nano-porous membrane with platinum electrodes coated on both sides has been designed, fabricated, tested, and analyzed. The maximum flow rate of 0.074 ml min(-1) V-1 cm(-2) for a membrane with porosity of 0.65 was obtained. A theoretical model, considering the head loss along the entire EO micropump system and the finite electrical double layer (EDL) effect on the flow rate, is developed for the first time to analyze the performance of the EO micropump. The theoretical and experimental results are in good agreement. It is revealed that the major head loss could remarkably decrease the flow rate, which thus should be taken into account for the applications of the EO micropump in various Lab-on-a-chip (LOC) devices. However, the effect of the minor head loss on the flow rate is negligible. The resulting flow rate increases with increasing porosity of the porous membrane and Ka, the ratio of the radius of the nanopore to the Debye length. (C) 2010 Elsevier Inc. All rights reserved.