Electrostatic disorder-induced interactions in inhomogeneous dielectricsR. Podgornik1, 2 and A. Naji3
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 in final form 16 March 2006
published online 5 April 2006
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.
82.70.-y - Disperse systems; complex fluids.
68.15.+e - Liquid thin films.
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