Effects of Microchannel Cross-Section and Applied Electric Field on Electroosmotic Mobility

In this work we report on the numerical and experimental investigation of the effects of channel cross-section and applied electric field on electroosmotic flow (EOF) mobility in polydimethylsiloxane (PDMS)/glass hybrid microchannels. The experimental results are used to calibrate and validate the simulation model to solve the Navier-Stokes equation for fluid flow and Poisson equation to resolve the external electric field. According to the Helmholtz Smoluchowski equation the electroosmotic mobility (mu_EO) is independent of channel cross-section and applied electric field. Contrary to the above relationship, the results presented in this work indicate that mu_EO is not constant but changes with channel cross-section as well as the applied electric field. The results of this work will be useful in determining the optimum channel dimensions for a desired electroosmotic velocity at a given applied electric field.