Aggregation of rod-like polyelectrolyte chains in the presence of monovalent counterions

TL;DR

This study uses molecular dynamics simulations to show that monovalent counterions can induce aggregation of similarly charged rod-like polyelectrolyte chains, with the critical charge density depending on counterion valency.

Contribution

It reveals the critical charge density for aggregation and relates it to counterion valency, providing new insights into polyelectrolyte behavior in the presence of monovalent ions.

Findings

Monovalent counterions induce aggregation at a specific charge density.

Critical charge density decreases with increasing counterion valency.

Effective interaction potential is linked to counterion distribution.

Abstract

Using molecular dynamics simulations, it is demonstrated that monovalent counterions can induce aggregation of similarly charged rod-like polyelectrolyte chains. The critical value of the linear charge density for aggregation is shown to be close to the critical value for the extended-collapsed transition of a single flexible polyelectrolyte chain, and decreases with increasing valency of the counterions. The effective interaction potential between two rod-like polyelectrolyte chains is measured, and is related to the angular distribution of the condensed counterions.