Electrolytes in the presence of a potential barrier: Diffusio-osmotic flow

Abstract

In this paper, we study the influence of a potential barrier in a symmetric electrolyte fluid embedded on a parallel plate. A generalisation of the Gouy-Chapman model is derived in the presence of this barrier and analytical solutions are obtained for the linearised regime and the electroosmotic flow for small barriers. The expressions are complemented with Lattice-Boltzmann simulations, determining the region where the linearisation works and extending the validity of the linearised regime when the height of the barrier increases. Finally the electroosmotic velocity profiles are analytically reproduced using the modified linearisation and compared to the simulations.