Max Planck Institute for Dynamics and Self-Organization, Am Faßberg 17, 37077 Göttingen, Germany.
Institute for the Dynamics of Complex Systems, Georg August Universität, 37077 Göttingen, Germany.
Phys Rev Lett. 2019 Oct 25;123(17):178003. doi: 10.1103/PhysRevLett.123.178003.
Liquid shells (e.g., double emulsions, vesicles, etc.) are susceptible to interfacial instability and rupturing when driven out of mechanical equilibrium. This poses a significant challenge for the design of liquid-shell-based micromachines, where the goal is to maintain stability and dynamical control in combination with motility. Here, we present our solution to this problem with controllable self-propelling liquid shells, which we have stabilized using the soft topological constraints imposed by a nematogen oil. We demonstrate, through experiments and simulations, that anisotropic elasticity can counterbalance the destabilizing effect of viscous drag induced by shell motility and inhibit rupturing. We analyze their propulsion dynamics and identify a peculiar meandering behavior driven by a combination of topological and chemical spontaneously broken symmetries. Based on our understanding of these symmetry breaking mechanisms, we provide routes to control shell motion via topology, chemical signaling, and hydrodynamic interactions.
液体壳（例如，双乳液、囊泡等）在机械平衡时容易受到界面不稳定性和破裂的影响。这对基于液体壳的微机器的设计提出了重大挑战，因为其目标是在保持稳定性和动力学控制的同时实现运动。在这里，我们通过使用各向异性弹性来对抗由壳运动引起的粘性阻力的不稳定性，并抑制破裂，从而提出了一种可控制的自推进液体壳的解决方案，我们使用各向异性弹性来稳定液体壳。我们通过实验和模拟证明，各向异性弹性可以抵消由壳运动引起的粘性阻力的不稳定性，并抑制破裂。我们分析了它们的推进动力学，并发现了一种由拓扑和化学自发破缺对称性共同作用驱动的奇特的蜿蜒行为。基于我们对这些对称破缺机制的理解，我们提供了通过拓扑、化学信号和流体动力学相互作用来控制壳运动的途径。
