On the elasticity of a single polyelectrolyte chain

TL;DR

This paper investigates the elastic properties of a single polyelectrolyte chain, revealing a new deformation regime at high forces through a self-consistent variational approach supported by simulations.

Contribution

It introduces a novel self-consistent variational method to analyze the elasticity of polyelectrolyte chains considering multiple length scales, unlike previous scaling analyses.

Findings

Elastic force is proportional to end-to-end distance at small forces.

A new deformation regime appears at high forces beyond the electrostatic blob size.

Results are supported by simulations and physical arguments.

Abstract

This paper discusses the elastic behavior of a single polyelectrolyte chain. A simple scaling analysis as in self avoiding walk chains are not possible, because three interplaying relevant length scales are involved, i.e., the Debye screening length and the Pincus blob size. Therefore a selfconsistent computation of an effective variational propagator is employed. It is shown that the elastic force f is proportional to the end to end distance R for small f. For larger forces we find a new regime, characterized by deformations larger than a computed electrostatic "blob size". These results are supported by simulations and intuitive physical arguments.