SIMULATIONS OF SOLVENT EFFECTS ON CONFINED ELECTROLYTES

Monte Carlo simulations are reported for the solvent primitive model (SPM) of the electrical double layer at electrically charged and neutral surfaces. Both solvent and ions are modeled as hard spheres with interactions governed by hard sphere and Coulomb interactions. Density profiles of solvent and ions and electrostatic potential profiles are presented for 1:1 electrolyte concentrations of 1 and 2 M at 300 K. Comparison of results at charged and neutral walls indicates that the density distribution of a dense solvent near a wall induces significant layering of ions and decrease of potentials in the double layer. This layering effect cannot be captured in simulations of the conventional primitive model (PM) of the double layer. The solvent induced steric ordering of electrolyte ions at a neutral wall can create a space charge layer.