ABSTRACT
I. INTRODUCTION Despite continued theoretical and experimental effort, the behavior of poly electrolyte solutions is less well understood than that of neutral polymer solutions [1,2]. Solutions of poly electrolyte chains have complex phase di agrams. Regardless of the a priori repulsive electrostatic interactions between the charged monomers of the chains, precipitation is observed in the pres ence of multivalent ions. With highly charged polyelectrolyte chains, the spatial distribution of charge is strongly inhomogeneous. The high charge density along the polymer chain produces a high electrostatic potential around it, and a fraction of the ions of opposite charge are in close proximity of the chain. A fraction of counterions is consequently located in the im mediate vicinity of the polymer chain; this phenomenon is called counterion condensation [3-9]. Precipitation of polyelectrolytes by multivalent salt has been studied for a long time [10-30] but remains poorly understood.
