Recycle Flows in Lab-on-Chip Applications Using Electroosmotic Effects

Abstract

Several lab-on-chip applications deal with the flow of fluids through microchannels. Some applications require recycle flows in such systems. In this work we show how this can be achieved in microfluidic systems using electroosmosis. The system consists of flow through a main channel and a side channel with a provision for recycle. The main flow is pressure-driven, and the recycle flow is achieved by imposing an electric field across the side channel. When the applied electric field is greater than a critical value, the flow in the side channel is reversed and recycle is induced. The critical applied electric field is investigated as a function of zeta potential. The effect of the applied electric field on pressure and flow rate in the main and side channels is analyzed. The influence of radius and position of the side channel on flow behavior has also been studied.