Modeling the Phase Behavior of Complex Coacervates formed from Polyelectrolytes and Surfactant Micelles

Oppositely-charged macromolecular species can undergo an associative phase separation, in a process known as complex coacervation. There has been significant interest in coacervation between two polyelectrolytes, however for many biological and industrial applications coacervation occurs between species where at least one of the components is not a linear polymer. This includes coacervates driven by charged proteins, colloids, or surfactant micelles. In this talk, we will show how we use a hybrid simulation and field theory calculation to capture the physics of liquid-liquid phase separation in polymer-surfactant micelle coacervates. This method is an extension of the transfer matrix approach developed by the authors. We demonstrate the importance of charge correlations between strongly-charged micellar surfaces, and we map out the phase behavior of these polyelectrolyte-surfactant micelle coacervates upon varying the strength of these correlations, the polyelectrolyte chain length, and micelle size surface charge density. We demonstrate qualitative agreement with experimental literature, and show that a coexistence exists between micelle-dilute and micelle-dense phases reflects a competition between charge correlations and micelle excluded volume.