Secondary microflows in electrokinetic transport with hydrodynamic slippage effect

Abstract

The secondary flow motion that is induced by curvature of microscale channel is thoroughly studied with simulation and experimental validation. The steady-state solution of the electroosmotic flow is achieved by applying the full Poisson-Boltzmann and the Navier-Stokes equations that are associated throughout the whole domain of the rectangular microchannel, made of either glass only or glass and polydimethylsiloxane. At the hydrophobic surface with curvature, the generalized Navier's slip boundary condition is applied. The particle streak velocimetry is performed by using an inverted epi-fluorescence microscope with tracer particle, which provides experimental verifications. We visualize the flow in a curved microchannel and compare the results with the simulation. Based on the agreements, it is concluded that our simulations exactly represent the curvature induced secondary flow, and are able to provide standard predictor for the relevant applications.