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Dynamics of active liquid interfaces


Adkins, Raymond et al. (2022), Dynamics of active liquid interfaces, Dryad, Dataset,


Controlling interfaces of phase separating fluid mixtures is key to creating diverse functional soft materials. Traditionally, this is accomplished with surface-modifying agents. Using a combination of experiment and theory, we study how mechanical activity shapes soft interfaces of a phase separating mixture of an active and a passive fluid. Chaotic flows in the active fluid give rise to giant interfacial fluctuations and non-inertial propagating active waves. At high activities, stresses disrupt interface continuity and drive droplet pinch- off. In this limit, we observe an active emulsion-like steady-state comprising finite-sized droplets that constantly break apart, fuse and exchange content. Furthermore, when in contact with a solid boundary, active interfaces exhibit non-equilibrium wetting transitions, where the fluid powered by active stress climbs the wall against gravity. These results demonstrate the promise of me- chanically driven interfaces for creating a new class of lifelike soft active mat- ter.


U.S. Department of Energy, Award: DE-SC0019733

National Science Foundation, Award: NSF-DMR-1720256

National Science Foundation, Award: NSF-DMR-2041459

National Science Foundation, Award: NSF-GRFP-1650114

National Science Foundation, Award: DMR-2011846

Human Frontier Science Program, Award: LT001065/2017- C