Conformation of a polyelectrolyte complexed to a like-charged colloid.

We report results from a molecular dynamics simulation on the conformations of a long flexible polyelectrolyte complexed to a charged sphere, both negatively charged, in the presence of neutralizing counterions in the strong Coulomb coupling regime. The structure of this complex is very sensitive to the charge density of the polyelectrolyte. For a fully charged polyelectrolyte the polymer forms a dense two-dimensional "disk," whereas for a partially charged polyelectrolyte the monomers are spread over the colloidal surface. A mechanism involving the overcharging of the polyelectrolyte by counterions is proposed to explain the observed conformations.