A Chaotic Electroosmotic Stirrer

Abstract

Two-dimensional, time-independent, and time-dependent electroosmotic flows driven by a uniform electric field in a conduit with nonuniform ζ potential distributions along its walls are investigated theoretically. The time-independent flow fields are computed with the aid of Fourier series. The series' convergence is accelerated so that highly accurate solutions are obtained with just a few terms in the series. The analytic solution is used to compute flow patterns for various distributions of the ζ potential along the conduit's boundaries. Subsequently, it is demonstrated that by time-wise periodic alternations of the ζ potentials, one can induce chaotic advection. This chaotic flow can be used to efficiently stir and mix fluids in microfluidic devices.