Discrete aqueous solvent effects and possible attractive forces

Discrete solvent effects on interacting charged and planar plates were studied in aqueous solution. The density profile of ions between the two plates, and the resulting interplate pressure were examined. When the two plates were separated from each other, the ion density was described using an effective Poisson-Boltzmann charge that is smaller than the nominal charge. The reduction in density resulted in reduced pressure relative to Poisson-Boltzmann predictions. The pressure was modified considerably at plate separations below 20 angstroms due to the solvent mediated short-range attraction between ions in the system.