Two-body polyelectrolyte mediated bridging interactions

TL;DR

This paper presents a theoretical study of polyelectrolyte bridging interactions between macroions, using a variational approach to analyze different coupling regimes and chain conformations, with implications for experimental systems.

Contribution

The work introduces a generalized variational method to analyze two-body polyelectrolyte bridging, revealing distinct strong and weak coupling solutions and conformations.

Findings

Identification of strong and weak coupling solution branches.

Analysis of chain conformations as weakly or strongly paired.

Discussion of effective macroion interactions in parameter space.

Abstract

We investigate theoretically polyelectrolyte bridging interactions on the two-body level. The model system is composed of two macroions with two oppositely charged flexible chains. The electrostatic interactions are treated on the Debye - H\" uckel level. The formal level of the theory is provided by the Feynman-Kleinert variational method generalized to include also self-interactions between polyelectrolyte segments. The variational equations are shown to exhibit two solution branches corresponding to {\sl strong} and {\sl weak} coupling, whereas conformations of the chain can be described as {\sl weakly} or {\sl strongly paired}. We investigate the effective pair interaction between the macroions in the parameter space and comment on the relevance of the calculation for bridging interactions in experimental context.