A Modified Random Phase Approximation of Polyelectrolyte Solutions

A. V. Ermoshkin; M. Olvera de la Cruz

doi:10.1021/ma034148p

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arXiv · cond-mat/0211493

A Modified Random Phase Approximation of Polyelectrolyte Solutions

A. V. Ermoshkin·M. Olvera de la Cruz

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Abstract

We compute the phase diagram of salt-free polyelectrolyte solutions using a modified Debye-Huckel Approach. We introduce the chain connectivity via the Random Phase Approximation with two important modifications. We modify the electrostatic potential at short distances to include a bound on the electrostatic attractions at the distance of closest approach between charges. This modification is shown to act as a hard core in the phase diagram of electrolyte solutions. We also introduce a cut-off on the integration of the modes of wave length smaller than the size over which the chains are strongly perturbed by the electrostatic interactions. This cut-off is shown to be essential to predict physical phase diagram in long chain solutions.

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A. V. Ermoshkin, M. Olvera de la Cruz. 2002-11-24. A Modified Random Phase Approximation of Polyelectrolyte Solutions. https://doi.org/10.1021/ma034148p

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