General solution to the electric double layer with discrete interfacial charges

TitleGeneral solution to the electric double layer with discrete interfacial charges
Publication TypeJournal Article
Year of Publication2012
AuthorsVangaveti S, Travesset A
Journal TitleJournal of Chemical Physics
Volume137
Pages064708
Date Published08
Type of ArticleArticle
ISBN Number0021-9606
Accession NumberWOS:000308048700055
KeywordsCOUNTERIONS, dynamics, electrolytes, image interactions, inhomogeneous coulomb fluids, inversion, planar surfaces, primitive model
Abstract

We provide extensive molecular dynamics simulations of counterion and coion distributions near an impenetrable plane with fixed discrete charges. The numerical results are described by an explicit solution that distinguishes the plasma (root A(c)/sigma > 3) and the binding regime (root A(c)/sigma < 3) where sigma is the ion diameter and A(c) = vertical bar e/nu vertical bar (nu is the surface charge density). In the plasma regime, the solution consists of a product of two functions that can be computed from simpler models and reveals that the effects of the discreteness of the charge extends over large distances from the plane. The solution in the binding regime consists of a Stern layer of width a and a diffuse layer, but contrary to standard approaches, the strong correlations between ions within the Stern layer and the diffuse layer require a description in terms of a "displaced" diffuse layer. The solution is found to describe electrolytes of any valence at all concentrations investigated (up to 0.4M) and includes the case of additional specific interactions such as van der Waals attraction and other generalizations. We discuss some open questions. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4739300]

URL<Go to ISI>://WOS:000308048700055
DOI10.1063/1.4739300
Alternate JournalJ. Chem. Phys.