Electrokinetically enhanced cross-stream particle migration in viscoelastic flows

Advancements in understanding the lateral migration of particles have helped in enhanced focusing in microfluidic devices. In this work, we investigate the effects of electrokinetics on particle migration in a viscoelastic flow, where the electric field is applied parallel to the flow. Through experiments and use of perturbation theory in conjunction with the reciprocal theorem, we show that the interaction of electrokinetic and rheological effects can result in an enhancement in migration by an order of magnitude. The theoretical analysis, in agreement with the experiments, demonstrates that the particles can be focused at different equilibrium positions based on their intrinsic electrical properties.