Electrostatic disorder-induced interactions in inhomogeneous dielectrics

¹ Department of Physics, Faculty of Mathematics and Physics, University of Ljubljana SI-1000 Ljubljana, Slovenia
² Department of Theoretical Physics, J. Stefan Institute - SI-1000 Ljubljana, Slovenia
³ Department of Physics, Technical University of Munich - D-85748 Garching, Germany

Received: 4 January 2006
Accepted: 16 March 2006

Abstract

We investigate the effect of quenched surface charge disorder on electrostatic interactions between two charged surfaces in the presence of dielectric inhomogeneities and added salt. We show that in the linear weak-coupling regime (i.e., when mean-field and Gaussian-fluctuations contributions are included), the image-charge effects lead to a non-zero disorder-induced interaction free energy between two surfaces of equal mean charge that can be repulsive or attractive depending on the dielectric mismatch across the bounding surfaces and the exact location of the disordered charge distribution.