Polyelectrolyte Networks: Elasticity, Swelling, and the Violation of the Flory - Rehner Hypothesis

TL;DR

This paper investigates the elastic and swelling behavior of polyelectrolyte networks, revealing that the classical Flory-Rehner hypothesis does not apply due to electrostatic interactions affecting network elasticity.

Contribution

It demonstrates the failure of the Flory-Rehner hypothesis in polyelectrolyte networks and introduces a comprehensive theory accounting for electrostatic effects on elasticity and swelling.

Findings

Flory-Rehner hypothesis does not hold for polyelectrolyte networks.

Electrostatic interactions significantly influence network modulus.

The equilibrium swelling can be estimated using a $c^{*}$-network assumption.

Abstract

This paper discusses the elastic behavior of polyelectrolyte networks. The deformation behavior of single polyelectrolyte chains is discussed. It is shown that a strong coupling between interactions and chain elasticity exists. The theory of the complete crosslinked networks shows that the Flory - Rehner - Hypothesis (FRH) does not hold. The modulus contains contributions from the classical rubber elasticity and from the electrostatic interactions. The equilibrium degree of swelling is estimated by the assumption of a $c^{*}$-network.