ABSTRACT
A lattice Boltzmann model (LBM) is used to simulate electroosmotic flow (EOF) in a rectangular microchannel with nonuniform surface potentials. The simulation results indicate that local circulations can occur near a heterogeneous region. The largest circulations, which imply the highest mixing efficiency due to convection and short-range diffusion, were found when the average surface potentials is zero. More importantly, we have illustrated that there is a trade-off between the mixing and flow efficiency in EOF microfluidics.