Electrokinetic transport with stokes flow in microfluidic-chip under asymmetric conditions of channel surface

Abstract

The behavior of the slip length and the long-range repulsion plays an essential role for design and operation in many of μTAS devices. We have developed the explicit model incorporated together the finite difference scheme for electrokinetic flow in rectangular microchannels encompassing Navier's boundary slip. The externally applied body force originated from between the nonlinear Poisson-Boltzmann field around the channel wall and the flow-induced electric field is employed in the equation of motion. It is evident that the fluid slip counteracts the effect by the electric double layer (EDL) and induces a larger flow rate. Particle streak imaging by fluorescent microscope has been applied to microchannels designed to allow for flow visualization of dilute latex colloids underlying the condition of simple fluid. We recognized the behavior of fluid slip at the hydrophobic surface of polydimethylsiloxane (PDMS) wall, from which the slip length was evaluated for different conditions. ？ 2006 Society for Chemistry and Micro-Nano Systems.