A modified random phase approximation of polyelectrolyte solutions

A. V. Ermoshkin*, M. Olvera De La Cruz

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

53 Scopus citations

Abstract

We compute the phase diagrams of salt-free polyelectrolyte solutions, using a modified Debye-Hückel approach. We introduce the chain connectivity via the random phase approximation with three modifications. First, we modify the electrostatic potential at short distances to include a boundary on the electrostatic attractions at the distance of closest approach between charges, which is important in semidilute solutions. This modification is shown to act as a hard core contribution in solutions of simple electrolytes. Second, we introduce a cutoff on the integration of the modes of wavelength smaller than the size over which the electrostatic attractions cannot be linearized and strongly perturbed chain are expected. A concentration-dependent cutoff is shown to be essential to predict physically reasonable phase diagrams. Third, ion condensation is included self-consistently. The modification does not give correct phase diagrams without the concentration-dependent cutoff. The combined modifications give phase diagrams in agreement with Monte Carlo simulations.

Original languageEnglish (US)
Pages (from-to)7824-7832
Number of pages9
JournalMacromolecules
Volume36
Issue number20
DOIs
StatePublished - Oct 7 2003

ASJC Scopus subject areas

  • Organic Chemistry
  • Polymers and Plastics
  • Inorganic Chemistry
  • Materials Chemistry

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