(N,V,T) Monte Carlo Simulations of the Electrostatic Interaction between Charged Colloids:  Finite Size Effects

We performed (N,V,T) Monte Carlo simulations of the ion distribution between two charged disks immersed in a large simulation cell. Ion−ion, ion−disk and disk−disk interactions are described in the framework of the primitive model. The purpose of these Monte Carlo simulations is to quantify the influence of interionic correlation forces on the stability of charged colloids. The net electrostatic and contact forces between the disks are calculated as a function of the counterion charge. While the same qualitative results were obtained for infinite charged lamellae, the finite size of the colloids has a strong influence on the different contributions to the net interparticle force. We also discuss the validity of the so-called Weak Overlap Approximation, which may be used to describe the interparticle force in a simplified treatment of colloidal suspensions based on the One Component Plasma approach.