Controlling interfaces of phase-separating fluid mixtures is key to the creation of diverse functional soft materials. Traditionally, this is accomplished with surface-modifying chemical agents. Using experiment and theory, we studied how mechanical activity shapes soft interfaces that separate an active and a passive fluid. Chaotic flows in the active fluid give rise to giant interfacial fluctuations and noninertial propagating active waves. At high activities, stresses disrupt interface continuity and drive droplet generation, producing an emulsion-like active state composed of finite-sized droplets. When in contact with a solid boundary, active interfaces exhibit nonequilibrium wetting transitions, in which the fluid climbs the wall against gravity. These results demonstrate the promise of mechanically driven interfaces for creating a new class of soft active matter.

中文翻译：

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主动液体界面动力学

控制相分离流体混合物的界面是创建多种功能性软材料的关键。传统上，这是通过表面改性化学试剂完成的。通过实验和理论，我们研究了机械活动如何塑造分离主动流体和被动流体的软界面。活性流体中的混沌流动引起巨大的界面波动和非惯性传播的活性波。在高活性下，应力会破坏界面连续性并驱动液滴生成，从而产生由有限尺寸液滴组成的乳液状活性状态。当与固体边界接触时，活动界面表现出非平衡润湿转变，其中流体克服重力爬升壁面。