Numerical Simulation of the Electrical Double Layer Based on the Poisson-Boltzmann Models for AC Electroosmosis Flows

P. Pham1, M. Howorth1, A. Planat-Chrétien1, and S. Tardu2
1Département des microTechnologies pour la Biologie et la Santé, CEA/LETI, Grenoble, France
2LEGI, Grenoble, France

In this paper, the analytical validation of Poisson-Boltzmann (PB) equation computed with COMSOL Multiphysics in the case of a polarized surface in contact with an electrolyte, is first presented.

COMSOL Multiphysics algorithms easily handle the highly nonlinear aspect of the PB equation. The limitations of the PB model, that considers ions as point like charges, are outlined.

To account for the steric effects of ion crowding at the charged surface, the Modified Poisson-Boltzmann model, proposed by Kilic et al., is analyzed for symmetric electrolytes. The MPB equation is then coupled to the complex AC electrokinetic and the Navier-Stokes equations to simulate the AC electroosmosis flow observed inside an interdigitated electrodes microsystem.