发表机构
Université de Bordeaux; Collège de France; Max Planck Institute for the Physics of Complex Systems; Meiji University（波尔多大学; 法兰西公学院; 马克斯·普朗克复杂系统物理研究所; 明治大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究揭示活性胶体筏在液滴内沿偏心轨道运动，通过各向异性变形接触线产生非往复游泳划水，从而推动宿主液滴，展示了集体活动经软边界变形转化为运动的机制。
AI 中文摘要
限制在液滴内的活性粒子可以使其宿主液滴运动。这种现象通常归因于封闭粒子对液体的直接流体动力学作用。在这里，我们揭示了一种不同的机制：我们证明，限制在水面薄油滴中的活性胶体自推进筏通常沿偏心轨道运动，从而以各向异性的方式周期性地使液滴的接触线变形。这种非往复变形起到游泳划水的作用，并根据低雷诺数游泳原理推动液滴。对于单个胶体，这种效应不存在，它源于筏固有的多体动力学，我们通过耦合粘性流体动力学和多体活性动力学的动力学模型捕捉了这一点。我们的结果表明，集体内部活动如何通过软约束边界的变形转化为运动。
英文摘要
Active particles confined in droplets can set their host droplet into motion. This phenomenon is usually attributed to direct hydrodynamic forcing by the enclosed particles. Here we reveal a different mechanism: we show that a self-propelled raft of active colloids confined in a thin oil droplet at the surface of water typically follows an off-centered orbit, thus periodically deforming the droplet's contact line in an anisotropic way. This non-reciprocal deformation acts as a swimming stroke and propels the droplet according to the principles of low-Reynolds-number swimming. The effect is absent for a single colloid and arises from the intrinsically many-body dynamics of the raft, which we capture with a dynamical model coupling viscous hydrodynamics and many-body active dynamics. Our results show how collective internal activity can be converted into locomotion through deformation of a soft confining boundary.
