ELECTRIC DOUBLE-LAYER INTERACTIONS IN REVERSE MICELLAR SYSTEMS - A MONTE-CARLO SIMULATION STUDY

The electrostatic contribution to the interaction between reverse micelles in water-in-oil microemulsions formed in the presence of ionizing surfactant is studied by means of Monte Carlo simulation. The inverted micelles are treated as spherical entities consisting of charged surfactant shell and aqueous core with neutralizing counterions. The distributions of simple ions in the core determined by simulation are compared with the predictions of the Poisson-Boltzmann approximation. A good agreement is observed, particularly for monovalent simple ions. The dispersion force due to the correlated fluctuations in ionic distribution within electroneutral micelles is found to be of comparable magnitude as classical van der Waals interaction and may represent a significant contribution to the total pair potential estimated from recent small angle neutron scattering (SANS) measurements of intermicellar correlations. © 1990 American Institute of Physics.