Flow and species transport control in grooved microchannels using local electrokinetic forces

We present numerical simulation results for flow and species transport control in grooved microchannels using locally applied electric fields, and zeta potential patterned groove surfaces. The resulting mixed electro-osmotic/pressure-driven flow enables entrapment and release of prescribed amounts of scalar species in the grooves. The groove size and shape determine the volume of the entrapped species. Depending on the local electric field and zeta potential, each groove can simultaneously contain up to two species. This framework allows control over the interspecies diffusion and mixing using simple flow kinematics, and it is easily applicable for electrically neutral species. We envision utilization of this technique for combinatorial chemistry experiments in a microchannel with multiple grooves, where each groove can be addressed (filled, emptied, or mixed) independently. Alternatively, the technique can be used for electronic cooling, where the grooves increase heat transfer surface area without the adverse effects of recirculating flow pattern. (c) 2007 American Institute of Physics.