Intermolecular adhesion in conducting polymers

TL;DR

This paper investigates how electronic interactions between charged conducting polymer chains influence their aggregation behavior in solution, revealing conditions that favor different structural phases.

Contribution

It introduces a minimal model to analyze electronic interactions and predicts a phase diagram for polymer aggregation based on charge density and persistence length.

Findings

Electronic energy decrease promotes chain aggregation.

Phase diagram includes unbound, loosely bound, and tightly bound states.

Electrostatic repulsion competes with attractive electronic interactions.

Abstract

We analyze the interaction of two conducting, charged polymer chains in solution using a minimal model for their electronic degrees of freedom. We show that a crossing of the two chains in which the polymers pass within Angstroms of each other leads to a decrease of the electronic energy of the combined system that is significantly larger than the thermal energy and thus promotes interchain aggregation. We consider the competition of this attractive interaction with the screened electrostatic repulsion and thereby propose a phase diagram for such polymers in solution; depending on the charge density and persistence length of the chains, the polymers may be unbound, bound in loose, braid-like structures, or tightly bound in a parallel configuration.