LMP Seminar: Phase separation in fluids driven by nonequilibrium chemical reactions

In living systems, liquid-liquid phase separation can occur at a nonequilibrium steady state (NESS) as opposed to thermal equilibrium. One way of sustaining a NESS in a biomolecular solution is by coupling molecular conformational changes to a chemical potential difference provided by a constant chemical fuel source, such as ATP. To investigate how this scenario alters the thermodynamic and kinetic properties of liquid-liquid phase separation, we introduce a molecular simulation approach for computing phase coexistence at a chemically driven NESS. We show that the interfacial tension between coexisting phases can be tuned systematically by altering the reactive fluxes of the driven chemical reactions in each phase. We then discuss the implications of this nonequilibrium interfacial tension for controlling the nucleation and growth kinetics of phase-separated droplets. Our work thus reveals a nonequilibrium mechanism for breaking the correlation between fast nucleation and strong driving forces that is typical of phase separation and self-assembly at thermal equilibrium.