Characterization of electroosmotic flow in rectangular microchannels

In this paper, the electroosmotic displacing process between two solutions (namely the same electrolyte of different concentrations) in a rectangular microchannel is studied theoretically and experimentally. Firstly, the electric potential and velocity field in a rectangular microchannel are obtained by solving the governing equations. Fourier transform method is used to solve the electrolyte concentration profile equation. The electric current versus time curve through the microchannel is predicted based on the concentration profile obtained. The current monitoring technique is then used to study the electroosmotic displacing process. The results from the measured current–time relations agree well with those from the prediction, suggesting a reliable theoretical model developed in this study.