Simulation Studies of Controlling Polymer Phase Separation and Nanoscale Self-Assembly via Binding-Induced Polarization

Binding-induced liquid-liquid phase separation is ubiquitous in biological and synthetic macromolecular systems, yet the connection linking how non-covalent interactions drive the phase transitions is still unknow. Changes in enthalpic interactions are expected to influence phase separation, and a fundamental understanding of the interplay between enthalpic and entropic changes due to supramolecular association and phase separation is necessary to predict phase transitions in associating systems. To clarify the enthalpic contribution to binding-induced phase separation, it is important to determine how binding-induced polarization drives phase separation in model polymer systems. We studied the enthalpic and entropic contributions during liquid-liquid phase separation and evaluate binding-induced self-assembly triggered by Lewis adduct formation using coarse-grained simulations. We model the adduct formation via reversible bonding that forms a permanent dipole upon association between the coarse-grained Lewis acids and Lewis bases. By focusing on the effects of polarization strength and the phase behavior of Lewis adduct systems, we gain a better understanding of binding-induced polarization causes large changes to the phase behavior of the system, opening the door for tunable nanoscale self-assembly. Finally, we interpret the simulation results are through simplified Flory-Huggins models with various parameters and discuss the short-comings of such approximations.