Self-Propulsion of Pure Water Droplets by Spontaneous Marangoni-Stress-Driven Motion
Self-Propulsion of Pure Water Droplets by Spontaneous Marangoni-Stress-Driven Motion
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DOI：
10.1103/physrevlett.113.248302
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发表时间：
2014-12-11
影响因子：
8.6
通讯作者：
Dauchot, Olivier
中科院分区：
文献类型：
--
作者：
Izri, Ziane;van der Linden, Marjolein N.;Dauchot, Olivier
我们报告自发运动在一个完全生物相容的系统组成的纯水滴在油表面活性剂介质的角鲨烷和单油酸甘油酯。来自液滴的水被反胶束溶液溶解，在每个液滴周围产生溶胀的反胶束的浓度梯度。根据最近提出的机制的简单概括，强平流和弱扩散条件允许在足够大的Peclet数下在各向同性颗粒系统中首次实验实现自发运动[S. Michelin，E. Lauga和D. Bartolo，Phys. Fluids 25，061701（2013）; S. Michelin和E. Lauga，J. Fluid Mech.747，572（2014）]。用高浓度的盐溶液代替水，用十四烷代替角鲨烷的实验证实了上述机理。目前的游泳液滴能够携带外部物体，如大胶体，盐晶体，甚至细胞。
We report spontaneous motion in a fully biocompatible system consisting of pure water droplets in an oil-surfactant medium of squalane and monoolein. Water from the droplet is solubilized by the reverse micellar solution, creating a concentration gradient of swollen reverse micelles around each droplet. The strong advection and weak diffusion conditions allow for the first experimental realization of spontaneous motion in a system of isotropic particles at sufficiently large Peclet number according to a straightforward generalization of a recently proposed mechanism [S. Michelin, E. Lauga, and D. Bartolo, Phys. Fluids 25, 061701 (2013); S. Michelin and E. Lauga, J. Fluid Mech. 747, 572 (2014)]. Experiments with a highly concentrated solution of salt instead of water, and tetradecane instead of squalane, confirm the above mechanism. The present swimming droplets are able to carry external bodies such as large colloids, salt crystals, and even cells.