Nucleation in multicomponent liquid mixtures

Phase separation of multicomponent liquid mixtures plays an integral part in many processes ranging from industry to cellular biology. While the nucleation of two-phase systems is well understood, it remains relatively unexplored how nucleation proceeds in multiphase systems, such as intracellular condensates. Here, we investigate the nucleation of a new droplet inside a multiphase system. To estimate the critical droplet size and the energy barrier, we used the string method, which can efficiently find transition pathways in highly dimensional energy landscapes. The results of the string method are consistent with the classical nucleation theory for both homogeneous and heterogeneous nucleation, where droplets nucleate inside one of the phases and at the interface of two phases, respectively. The heterogeneous nucleation results in lower energy barriers when the nucleating phase partially wets the preexisting two phases. These results provide the guiding principles for the analysis of nucleation in multiphase systems, which can proceed in several steps.