Non-equilibrium capillary self-assembly

Existing, well-established principles of interfacial capillary self-assembly focus on the behavior of such systems at equilibrium. Inspired by recent experiments involving microscopic colloids, we herein study experimentally and theoretically the structural rearrangements between metastable states of clusters of millimetric spheres in non-equilibrium environments. The structural rearrangements are driven by a field of chaotic Faraday waves, which in turn play the role of an active bath. In contrast to colloids, inertial effects are non-negligible in our macroscopic system, prompting the development of a Langevin model of the noise-driven particle dynamics, informed by the fundamental aspects of the fluid system. We rationalize the occupation statistics and transition probabilities of the clusters, thereby informing new directions for non-invasive, directed self-assembly at the macroscale.