(403f) Constraint Release in Entangled Liquid Coacervates Made from Oppositely Charged Polyelectrolytes

Mixtures of oppositely charged polyelectrolytes can phase separate to form a polymer rich coacervate phase, used in many technological applications and biological systems. Predicting coacervate dynamics is important for determining processing conditions and macromolecule transport in the coacervate. We developed a scaling theory predicting the dynamics of unentangled and entangled liquid coacervates made from polyelectrolytes of equal (symmetric) or unequal (asymmetric) linear charge density. We find high charge density polymers are dynamically coupled to the low charge density polymer even in the unentangled regime. We predict that entangled coacervates have multiple regimes depending on whether the high charge density polymer reptates along the tube formed by other high charge density chains or along a tube formed by low charge density chains. In the latter case, topological constraints imposed by the low charge density chains are dynamic, which modifies coacervate transport and rheology through a process called constraint release. In this work, we develop a scaling model to predict the effects of constraint release on entangled asymmetric coacervates, where the low and high charge density polymers have different conformations. We find that the regimes dominated by tube rearrangement are broader in asymmetric coacervates as compared to symmetric coacervates. Constraint release also weakens the concentration dependence of viscosity in regimes dominated by reptation of the high charge density chains and modifies the viscosity dependence on polymer degree of polymerization.