Interaction between charged anisotropic macromolecules: Application to rod-like polyelectrolytes

TL;DR

This paper extends the DLVO theory to anisotropic, rod-like macromolecules, providing a framework to compute their effective interactions and exploring implications for phase behavior.

Contribution

It introduces a generalized approach for anisotropic macromolecule interactions, specifically applied to rod-like polyelectrolytes, with analytical and numerical methods.

Findings

Effective interaction remains anisotropic at all distances.

Analytical approximation agrees well with numerical results.

Insights into phase properties of rod-like colloids.

Abstract

In this paper we propose a framework allowing to compute the effective interactions between two anisotropic macromolecules, thereby generalizing the DLVO theory to non spherical finite size colloids. We show in particular that the effective interaction potential remains anisotropic at all distances and provide an expression for the anisotropy factor. We then apply this framework to the case of finite rod-like polyelectrolytes. The calculation of the interaction energy requires the numerical computation of the surface charge profiles, which result here from a constant surface potential on the rod-like colloids. However, a simplified analytical description is proposed, leading to an excellent agreement with the full numerical solution. Conclusions on the phase properties of rod-like colloids are proposed in this context.