Nonequilibrium interfacial properties of chemically driven fluids

Biomolecular mixtures can control the formation of condensed droplets by coupling chemical reactions to conformational state transitions of the phase-separating molecules.

When this coupling differs between the interior and exterior of the droplets, distinct nonequilibrium interfacial properties can arise.

Here, we employ a minimal model of chemically driven fluids in order to study changes in the interfacial tension away from equilibrium.

Droplet nucleation kinetics and the roughness of macroscopic interfaces between coexisting phases indicate that the nonequilibrium interfacial tension can deviate from the equilibrium value, depending on whether the driven chemical reaction rate is increased or decreased inside the droplets.

We understand these results using a predictive theory based on an effective thermodynamic equilibrium for each phase and the interface.