Ion–ion correlations in polyelectrolyte solutions: Hard sphere counterions
- 1 July 1993
- journal article
- research article
- Published by AIP Publishing in The Journal of Chemical Physics
- Vol. 99 (1) , 497-514
- https://doi.org/10.1063/1.465775
Abstract
The intimately related mechanisms of macroion screening and ion–ion correlations in electrolyte solutions are investigated with the aim to explore the simplest theoretical estimations of the latter on the former. The Poisson–Boltzmann theory of macroion screening in electrolyte solutions was developed under two important assumptions. Specifically, the correlated motion of the mobile ions is ignored by identifying the mean field electrostatic potential with the potential of average force and, moreover, only point charges are considered so that finite size effects are not accounted for. Utilizing the generalized van der Waals free energy density functional formulation for inhomogeneous fluids, we obtain simple corrections to the Poisson–Boltzmann result where both these mechanisms are treated in local and nonlocal approximations. By incorporating a somewhat more realistic short range repulsive interaction, the asymptotic instability encountered in the point particle case is avoided and self‐consistent density profiles can be computed. Nonlocal approximations are shown to be thermodynamically consistent in terms of the contact theorem for the osmotic pressure, and excellent agreement with Monte Carlo simulation is achieved even at high electrostatic coupling and with large particles.Keywords
This publication has 81 references indexed in Scilit:
- A family of equivalent expressions for the pressure of a fluid adjacent to a wallThe Journal of Chemical Physics, 1991
- Colloid stability: The forces between charged surfaces in an electrolyteThe Journal of Chemical Physics, 1991
- Highly asymmetric electrolyte: Triplet correlation functions from simulation in one- and two-component model systemsThe Journal of Chemical Physics, 1991
- Do variational formulations for inhomogeneous density functions lead to unique solutions?The Journal of Chemical Physics, 1991
- The electric double layer around an isolated spherical macroionElectrochimica Acta, 1991
- Shape fluctuations in ionic micellesThe Journal of Physical Chemistry, 1989
- Widom's method for uniform and non-uniform electrolyte solutionsMolecular Physics, 1988
- Double-layer forces in ionic micellar solutionsThe Journal of Physical Chemistry, 1987
- Phase equilibria of fluid interfaces and confined fluidsMolecular Physics, 1987
- Electrostatic interactions in colloidal solutions: Comparison between primitive and one-component modelsThe Journal of Chemical Physics, 1986