Electrokinetic flow control for composition modulation in a microchannel

Abstract

A numerical and experimental study of the injection into a microchannel of a fluid with a spatially modulated composition is presented. The investigation employs test structures constructed in polydimethylsiloxane by standard replica molding. Fluid-flow simulations are compared to flow results obtained by fluorescence microscopy experiments. Results show that for a given channel dimension, the desired modulation of the solution composition is only possible below a threshold frequency. The value of the threshold frequency is dependent on channel size as well as flow rate. Experimental results are in accord with numerical simulations and theoretical considerations.