Modeling of Electrokinetic Mixing in Lab on Chip Microfluidic Devices

Abstract

This dissertation summarize a modeling of electrokinetic mixing employing electro-osmotic stationary and time-dependent micropumps via alternate zeta potential patches on the lower surface of the mixing chamber in lab on chip microfluidic device. Electro-osmotic flow is augmented using different model designs with alternate zeta potential values such as 25mV, 50mV and 100mV respectively to achieve high mixing efficiency in electrokinetically driven microfluidic system. The enhancement of mixing via alternate opposing zeta potentials is studied using Finite Element Modeling. Simulation 2D and 3D workflow involves designated steps such as setting up the model environment, creating geometric objects, stipulating materials and boundary conditions, meshing and post analyzing the results. An electric contours and concentration gradients are derived using a Navier-Stokes for incompressible flow, convection-diffusion equation and Helmholtz-Smoluchowski slip velocity respectively. The effect of magnitude of zeta potential, number of alternate patches etc. are studied in detail. In addition, 2D results are compared with 3D results to demonstrate the significance of 3D model in microfluidic design process.