Electrokinetic membrane pumping flow model in a microchannel

Abstract

A microfluidic pumping flow model driven by electro-osmosis mechanisms is developed to analyze the flow characteristics of aqueous electrolytes. The pumping model is designed based on a single propagative rhythmic membrane contraction applied on the upper wall of a microchannel. The flow lubrication theory coupled with a nonlinear Poisson–Boltzmann equation is used to model the microchannel unsteady creeping flow and to describe the distribution of the electric potential across the electric double layer. A generic solution is obtained for the Poisson–Boltzmann equation without the Debye–Hückel linearization. The effects of zeta potential, Debye length, and electric field on the potential distribution, pressure distribution, velocity profiles, shear stress, and net flow rate are computed and interpreted in detail. The results have shown that this electrokinetic membrane pumping model can be used to understand microlevel transport phenomena in various physiological systems. The proposed model can also be integrated with other microfluidic devices for moving microvolume of liquids in artificial capillaries used in modern biomedical applications.