Electrostatic-Interaction-Induced Phase Separation
in Solutions of Flexible-Chain Polyelectrolytes

Yu. A. Budkov^a,*, A. L. Kolesnikov^b, E. A. Nogovitsyn^b, and M. G. Kiselev^a

^a Institute of Solution Chemistry, Russian Academy of Sciences, ul. Akademicheskaya 1, Ivanovo, 153045 Russia

^b Ivanovo State University, ul. Ermaka 37, Ivanovo, 153025 Russia

*e-mail: urabudkov@rambler.ru

Received November 14, 2013;
Revised Manuscript Received March 6, 2014

Abstract—A model of a polyelectrolyte solution has been formulated on the basis of the formalism of the ther-
modynamic perturbation theory. Macromolecules have been described in terms of the model of a flexible chain
with an excluded volume and a variable electrical charge. During construction of the thermodynamic perturba-
tion theory, a set of three independent subsystems—polyelectrolyte macromolecules placed in a structureless
charge background of counterions, counterions placed in a structureless charge background of macromolecules,
and Coulomb gas ions of a low-molecular-mass salt—has been taken as the reference system. In the framework
of this model, liquid–liquid phase separation due to strong correlation-induced attraction has been predicted.
The behavior of the degree of ionization over a wide monomer concentration range, including the region of
phase separation either in a salt-free solution or in the presence of univalent ions of a low-molecular-mass salt
in the solution, has been studied. It has been shown that macromolecules in the coexisting phases should have
different degrees of ionization. The occurrence of phase separation under normal conditions in the case when
dimethylformamide is taken as a solvent and the nonoccurrence of this phase separation in the case of aqueous
solutions of flexible-chain polyelectrolytes are predicted.

DOI: 10.1134/S0965545X14050022

Pleiades Publishing home page | journal home page | top

If you have any problems with this server, contact webmaster.