Numerical analysis of non-uniform electric field effects on induced charge electrokinetics flow with application in micromixers

Abstract

Induced charge electrokinetics (ICEK) has recently expanded its range of applications in biomedical engineering due to its high potential for being used in particle/cell manipulation platforms, micromixers, micropumps, and microvalves. In these devices, the generated microvortices around conducting hurdles/electrodes are used in order to achieve the desired operations. In the present study, the influences of non-uniform electric field on the generated microvortices around a conducting cylinder are analyzed in a micromixer. The electric field non-uniformities are produced either by pin-plate electrodes or by geometrical configuration. Results show that inhomogeneous electric fields lead to reduction of the induced zeta potential (IZP) and the microvortices velocity around the cylinder in the majority of the studied cases. However, imposing two electric fields with appropriate directions or positioning the cylinder in a suitable location enhances the IZP reductions. In this study, such electric fields are utilized in the ICEK micromixer for investigation of their effects on the mixing efficiency. Based on our findings, it is demonstrated that the generated electric field by two electrodes with angle of 30° increases the mixing efficiency from 69.07% to 96.89%. The present study provides new insights into the effects of non-uniform electric field on the IZP over a conducting hurdle and the generated microvortices in ICEK flows with an application in lab-on-a-chip (LOC) devices such as micromixers, microvalves, micropumps, and particle/cell separators.