Potential and Ions Distribution inside Reversed Micelles in Equilibrium with an Electrolyte Solution

The Poisson-Boltzmann equation for the charges hosted in the water dispersed into a reversed micelle in equilibrium with an uni-univalent electrolyte aqueous solution is considered. The solution is looked for in a form of a series as reported in literature for similar problems.

Thermodynamic equilibrium allows to calculate the concentration in the micellar centre and the mean concentration of the counterions and of the co ions inside the reverse micelle. The calculated concentrations are compared with the experimental values measured by AAS for sodium AOT micelles.

The agreement is rather satisfying for micelles in equilibrium with NaCl and LiCl aqueous solutions while some discrepancy is present for the Na⁺ concentration in the dispersed water of the reversed micelles in equilibrium with KCl solutions.

The validity of an approximation used in a model previously described to rationalize the results of experiments of protein uptaking is discussed.