Monte-Carlo simulations of star-branched polyelectrolyte micelles

The concentration profiles of monomers and counterions in star-branched polyelectrolyte micelles are calculated through Monte-Carlo simulations, using the simplest freely-jointed chain model. We have investigated the onset of different regimes corresponding to the spherical and Manning condensation of counterions as a function of the strength of the Coulomb coupling. The Monte-Carlo results are in fair agreement with the predictions of Self-Consistent-Field analytical models. We have simulated a real system of diblock copolymer micelles of (sodium-polystyrene-sulfonate)(NaPSS)-- (polyethylene-- propylene)(PEP) with f=54 hydrophilic branches of N=251 monomers at room temperature in salt-free solution and compared the calculated form factor with our neutron-scattering data.