Structure of strongly charged polyelectrolyte solutions

TL;DR

This study combines molecular dynamics simulations and recent theory to analyze density correlations in highly charged polyelectrolyte solutions, achieving good agreement with experiments at intermediate scales but discrepancies at very low wavevectors.

Contribution

It provides a quantitative comparison of theory, simulation, and experiments for polyelectrolyte solutions without adjustable parameters, highlighting areas of agreement and discrepancy.

Findings

Agreement with experiments for structure factor at intermediate wavevectors

Consistent osmotic pressure results across theory, simulation, and experiment

Discrepancy with scattering data at low wavevectors showing large intensities

Abstract

Molecular dynamics simulation and recent theory are used to examine density correlations in semidilute solutions of highly charged, intrinsically flexible and hydrophilic polyelectrolytes in low salt. Quantitative comparison with no adjustable parameters is made with recent scattering and osmometry experiments. Agreement is found for the polymer-polymer structure factor at intermediate wavevectors q with varying chain charge fraction f. Theory is also in agreement with simulation and experiment for the osmotic pressure, but not with q -> 0 extrapolations of scattering data that show anomalously large intensities at low q.