title: Ion-mediated interactions between net-neutral slabs: Weak and strong disorder effects.
abstract: We investigate the effective interaction between two randomly charged but otherwise net-neutral, planar dielectric slabs immersed in an asymmetric Coulomb fluid containing a mixture of mobile monovalent and multivalent ions. The presence of charge disorder on the apposed bounding surfaces of the slabs leads to substantial qualitative changes in the way they interact, as compared with the standard picture provided by the van der Waals and image-induced, ion-depletion interactions. While, the latter predict purely attractive interactions between strictly neutral slabs, we show that the combined effects from surface charge disorder, image depletion, Debye (or salt) screening, and also, in particular, their coupling with multivalent ions, give rise to a more diverse behavior for the effective interaction between net-neutral slabs at nano-scale separations. Disorder effects show large variation depending on the properly quantified strength of disorder, leading either to non-monotonic effective interaction with both repulsive and attractive branches when the surface charges are weakly disordered (small disorder variance) or to a dominating attractive interaction that is larger both in its range and magnitude than what is predicted from the van der Waals and image-induced, ion-depletion interactions, when the surfaces are strongly disordered (large disorder variance).
authors.affiliation: School of Physics, Institute for Research in Fundamental Sciences (IPM), Tehran 19395-5531, Iran.
authors.forename: Malihe
authors.initials: M
authors.lastname: Ghodrat
authors.affiliation: School of Physics, Institute for Research in Fundamental Sciences (IPM), Tehran 19395-5531, Iran.
authors.forename: Ali
authors.initials: A
authors.lastname: Naji
authors.affiliation: School of Physics, Institute for Research in Fundamental Sciences (IPM), Tehran 19395-5531, Iran.
authors.forename: Haniyeh
authors.initials: H
authors.lastname: Komaie-Moghaddam
authors.affiliation: Department of Theoretical Physics, J. Stefan Institute, SI-1000 Ljubljana, Slovenia.
authors.forename: Rudolf
authors.initials: R
authors.lastname: Podgornik