Bubble Free High Efficiency Electroosmotic Pumps

In generating high electroosmotic flows for use in microfluidic pumps, a limiting factor is faradaic reactions which appear at high electric fields. These reactions lead to higher power consumption and bubble generation at the electrodes. We are proposing a novel technique that can limit and even prevent gas generation. This will extend the current range of operation of electroosmotic pumps. This is achieved by applying a unidirectional pulsed DC voltage waveform. The optimum pulse voltage waveform (OPW) tested is based on a theoretical model developed by the authors [1]. The power consumed and the efficiency of an electroosmotic pump under the pulsed DC voltage is measured experimentally and compared with the conventional bipolar rectangular voltage waveform (BRW). Results show an increase in the efficiency for the OPW when compared to the BRW. This increase in efficiency is obtained by preventing the reverse cycle in the BRW which flows against the pumping direction.