(443a) Interconversion-Controlled Liquid-Liquid Phase Separation of a Molecular Chiral Model

Liquid-liquid phase separation of fluids exhibiting interconversion between alternative states is a ubiquitous phenomenon, which can explain fluid polyamorphism and may impact biological function. However, molecular-level insight on the interplay between competing forces that drive and resist phase separation in interconverting fluids remains elusive. Here, we utilize a three-dimensional off-lattice model of enantiomers with tunable chiral interconversion and interaction properties, to elucidate the essential physics underlying the stabilization and tunability of phase separation in fluids with interconverting states. We show that quenching such a system below the liquid-liquid critical temperature results in demixing via spinodal decomposition and, simultaneously, mixing via chiral interconversion. The competition between negative-diffusion demixing and interconversion-driven remixing results in micro-phase phase separation, kinetically arrested by the interconversion of enantiomers. We have also found that the competition and mutual coupling between the enantiomer interconversion and diffusion make the effective diffusion coefficient to be strongly dependent on the interconversion rate and the size of micro-phase domains. These findings provide novel insights on how the interplay between kinetics and thermodynamics define the steady-state morphology of phase transitions in fluids with interconverting molecular or supramolecular states.