Ma. Carignano et N. Dan, DENSITY INHOMOGENEITIES OF HIGHLY-CHARGED POLYELECTROLYTE SOLUTIONS CONFINED BETWEEN UNCHARGED AND NONADSORBING WALLS, Langmuir, 14(13), 1998, pp. 3475-3478
Monte Carlo simulations are used to study the density profile of dilut
e and semidilute solutions of highly charged polyelectrolytes confined
between uncharged and nonadsorbing walls. We find that the density pr
ofile displays oscillations whose wavelength corresponds to that of co
rrelations in bulk polyelectrolyte solutions. The amplitude of the osc
illations increases with chain molecular weight. The density oscillati
ons observed cannot be attributed to the confining walls, poor backbon
e solubility, colloidal-like ordering, or nonuniform distribution of c
ounterions. We conclude that the correlations in polyeletrolyte soluti
ons must be due to a balance between the segment-segment electrostatic
interactions and the chains' translational entropy.