Ultrasonic chaining of emulsion droplets
Ultrasonic chaining of emulsion droplets
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DOI：
10.1103/physrevresearch.3.043157
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发表时间：
2021-12-03
影响因子：
4.2
通讯作者：
Hoyos, Mauricio
中科院分区：
文献类型：
--
作者：
Abdelaziz, Mohammed A.;Diaz, Jairo A. A.;Hoyos, Mauricio
超声波悬浮器中捕获的乳液液滴会以固体球所不具备的方式自行组织。单分散乳液液滴不是聚结成平面胶体晶体，而是形成单列链。这些链的集体行为及其对附近液滴的影响表明，它们的组成液滴正在绕其共同轴快速旋转。这种声学诱导的旋转还可以区分液滴和固体球，并自然地解释了液滴形成链的倾向。在这种解释中，实心球体不会形成链，因为它们不旋转。我们通过模型系统演示了链到晶体的转变，其中流体乳液液滴可以光聚合成固体球体，而不会显着改变其他材料特性。该实验系统的行为在数量上与声悬浮器中旋转球体的声流体动力学模型一致。因此，本研究引入声驱动旋转作为引导声悬浮物质自组织的机制。
Emulsion droplets trapped in an ultrasonic levitator organize themselves in a way that solid spheres do not. Rather than coalescing into planar colloidal crystals, monodisperse emulsion droplets instead form single-file chains. These chains' collective behavior and their influence on nearby droplets suggest that their constituent droplets are spinning rapidly around their common axis. Such acoustically induced spinning also distinguishes fluid droplets from solid spheres and naturally accounts for the droplets' propensity to form chains. In this interpretation, solid spheres do not form chains because they do not spin. We demonstrate the chain-to-crystal transition with a model system in which fluid emulsion droplets can be photopolymerized into solid spheres without significantly changing other material properties. The behavior of this experimental system is quantitatively consistent with an acoustohydrodynamic model for spinning spheres in an acoustic levitator. This study therefore introduces acoustically driven spinning as a mechanism for guiding self-organization of acoustically levitated matter.