AbstractA numerical solution of the nonlinear Poisson‐Boltzmann equation (PBE) is presented for a system of spherical micelles with counterfoil binding. The approach investigates the following effects on ion micelle interactions, (i) total surface charge, (ii) competitions of different counter ions on micellar surfaces and (iii) surface potential determination. The theory is applied to interpret the ion activities in micellar solution as measured by ion‐selective electro