Effects of Associative Interactions on the Phase Behavior of Complex Coacervates

Abstract

Associative polymer networks have shown major promise in the fabrication of self-healing and responsive materials. They can also serve as simple models to study more complex biological systems in which transient interactions play an important role. In this work, we investigate the properties of charged polymer blends whose constituents are capable of creating dynamic bonds. We model dynamic bonds as harmonic springs with additional bond formation energy, ε a , which can be adjusted to influence the reaction rates for binding and unbinding. We show that varying the number of binding sites on the chains and ε a has a major effect on the resulting phase diagram. We further investigate the diffusive behavior of the coacervates. We also study how the network structure changes with varying number of active site, and increasing ε a , and identify the values which result in the network percolation. Lastly, we explore the possibility of inducing orthogonal phase separation by introducing a second type of binding site, which cannot interact with the first kind.