Density inhomogeneities of highly charged polyelectrolyte solutions confined between uncharged and nonadsorbing walls

Monte Carlo simulations are used to study the density profile of dilute and semidilute solutions of highly charged polyelectrolytes confined between uncharged and nonadsorbing walls. We find that the density profile displays oscillations whose wavelength corresponds to that of correlations in bulk polyelectrolyte solutions. The amplitude of the oscillations increases with chain molecular weight. The density oscillations observed cannot be attributed to the confining walls, poor backbone solubility, colloidal-like ordering, or nonuniform distribution of counterions. We conclude that the correlations in polyeletrolyte solutions must be due to a balance between the segment-segment electrostatic interactions and the chains' translational entropy.