title: Self-consistent field model for strong electrostatic correlations and inhomogeneous dielectric media.
abstract: Electrostatic correlations and variable permittivity of electrolytes are essential for exploring many chemical and physical properties of interfaces in aqueous solutions. We propose a continuum electrostatic model for the treatment of these effects in the framework of the self-consistent field theory. The model incorporates a space- or field-dependent dielectric permittivity and an excluded ion-size effect for the correlation energy. This results in a self-energy modified Poisson-Nernst-Planck or Poisson-Boltzmann equation together with state equations for the self energy and the dielectric function. We show that the ionic size is of significant importance in predicting a finite self energy for an ion in an inhomogeneous medium. Asymptotic approximation is proposed for the solution of a generalized Debye-Hückel equation, which has been shown to capture the ionic correlation and dielectric self energy. Through simulating ionic distribution surrounding a macroion, the modified self-consistent field model is shown to agree with particle-based Monte Carlo simulations. Numerical results for symmetric and asymmetric electrolytes demonstrate that the model is able to predict the charge inversion at high correlation regime in the presence of multivalent interfacial ions which is beyond the mean-field theory and also show strong effect to double layer structure due to the space- or field-dependent dielectric permittivity.
authors.affiliation: Department of Mathematics, Institute of Natural Sciences, and MoE Key Laboratory of Scientific and Engineering Computing, Shanghai Jiao Tong University, Shanghai 200240, China.
authors.forename: Manman
authors.initials: M
authors.lastname: Ma
authors.affiliation: Department of Mathematics, Institute of Natural Sciences, and MoE Key Laboratory of Scientific and Engineering Computing, Shanghai Jiao Tong University, Shanghai 200240, China.
authors.forename: Zhenli
authors.initials: Z
authors.lastname: Xu
mesh_terms: D003198:Computer Simulation; D004573:Electrolytes / Q000737:chemistry*; D008956:Models, Chemical; D009010:Monte Carlo Method; D012996:Solutions; D055672:Static Electricity; D014867:Water / Q000737:chemistry
chemical_list: D004573:Electrolytes; D012996:Solutions; D014867:Water