Charge distribution on annealed polyelectrolytes

Abstract. We investigate the equilibrium charge distribution along a single annealed polyelectrolyte chain under dierent conditions. The coupling between the conformation of the chain and the local charge distribution is described for various solvent qualities and salt concentration. In salt free solution, we nd a slight charge depletion in the central part of the chain: the charges accumulate at the ends. The eect is less important if salt is added to the solution since the charge inhomogeneity is localized close to the chain ends over a distance of order of the Debye length. In the case of poor solvent conditions we nd a dierent charge per monomer in the beads and in the strings in the framework of the necklace model. This inhomogeneity leads to a charge instability and a rst order transition between spherical globules and elongated chains. PACS. 61.25.Hq Macromolecular and polymer solutions; polymer melts; swelling { 36.20.Ey Conformation (statistics and dynamics) { 05.90.+m Other topics in statistical physics, thermodynamics, and nonlinear dynamical systems