On the effect of temperature on the reentrant condensation in polyelectrolyte-liposome complexation

TL;DR

This study investigates how temperature influences the formation of polyelectrolyte-liposome clusters, revealing that aggregation is driven by a thermally-activated process, which sheds light on the stability and nature of these clusters.

Contribution

It demonstrates that the aggregation of polyelectrolyte-liposome complexes is governed by a thermally-activated mechanism, providing new insights into their formation and stability.

Findings

Aggregation is thermally activated.

Temperature affects cluster stability.

Clusters may be equilibrium or metastable.

Abstract

In systems of highly charged linear polyelectrolytes and oppositely charged colloidal particles, long-lived clusters of polyelectrolyte-decorated particles form in an interval of concentrations around the isoelectric point, where reentrant condensation connected to charge inversion of cluster is observed. The mechanisms that drive the aggregation and stabilize, at the different polymer/particle ratios, a well defined size of the aggregates are not completely understood. Moreover, a central question still remains unanswered, i.e., whether the clusters are true equilibrium or metastable aggregates. To elucidate this point, in this work, we have investigated the effect of the temperature on the formation of the clusters. We employed liposomes built up by DOTAP lipid interacting with a simple anionic polyion, sodium polyacrylate, over an extended concentration range below and over the isoelectric condition. Our results show that the aggregation process can be described by a thermally-activated mechanism.