Double layer forces between heterogeneous charged surfaces

Abstract

In this paper we study the double layer interaction between two heterogeneous surfaces of either constant charge or constant potential. The surface heterogeneities are assumed to be distributed on periodic lattices of arbitrary structure. General expressions for the 3-D electrostatic potential distribution and the interaction free energy between the two surfaces are given. Asymptotic forms and numerical examples for the interaction potential are provided for the symmetric lattice problem. In general, the interaction potential or osmotic pressure decays exponentially at large separations. When a nonuniform, but net neutral, surface interacts with a uniform surface (charged or uncharged), the ..