发表机构
Max Planck Institute for Dynamics and Self-Organization; Institute for Theoretical Physics, University of Göttingen（马克斯·普朗克动力学与自组织研究所; 哥廷根大学理论物理研究所）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文通过薄界面近似推导液滴速度表达式，揭示液滴在化学梯度中向低稳定性区域（相图临界点附近）移动的普遍机制，为设计液滴运动提供新途径。
AI 中文摘要
复杂环境中的液滴常遇到驱动其推进的组成梯度。例如，表面活性剂梯度通过马兰戈尼效应诱导表面张力驱动的推进。在此，我们表明即使在没有表面活性剂的情况下，这种推进也能普遍产生。采用薄界面近似，我们推导出一个紧凑的液滴速度表达式，该表达式涉及液滴尺寸、粘度、表面张力对调控组分的敏感性以及该组分的化学势梯度。我们的理论揭示，液滴向稳定性较低的区域移动，这体现在相图的形态中，尤其是在临界点附近。数值模拟证实了这些结果，为从复杂流体的相行为预测和设计液滴运动建立了一条通用途径。
英文摘要
Droplets in complex environments often encounter compositional gradients that drive their propulsion. For example, surfactant gradients induce surface-tension-driven propulsion via the Marangoni effect. Here, we show that such propulsion emerges generically, even in the absence of surfactants. Employing a thin-interface approximation, we derive a compact expression for the droplet velocity in terms of droplet size, viscosity, the sensitivity of surface tension to a regulating component, and the chemical potential gradient of that component. Our theory reveals that droplets move toward regions of lower stability, as encoded in the morphology of the phase diagram, particularly near critical points. Numerical simulations confirm these results, which establish a general route to predicting and designing droplet motility from the phase behavior of complex fluids.
Comments7 pages, 5 figures, and Appendix
