Modeling microparticles' path in DEP-FFF microfludic devices

Abstract

This article documents the development of a dynamic model for predicting the trajectory of microparticles in a DEP-FFF microfluidic device. The electrode configuration is such that the top and bottom surfaces support multiple finite sized electrodes in the range of few micrometers. The electric potential inside the microchannel takes the form of Laplace equation while the equations of motion are based on Newton's second law. The forces considered include that due to inertia, drag, gravity, buoyancy and dielectrophoresis. All governing equations are solved using finite difference method with a spatial step size of 0.5 μm and temporal step size of 10−4s. In addition, a parametric study is carried out in order to understand the individual influence of operating and geometric parameters on the path of microparticles. The parameters considered include microparticle radius, actuation voltage, volumetric flow rate and microchannel height. It is found that all parameters influence the transient trajectory of microparticles while only a few parameters influence the final levitation height of microparticles.