Self‐Propulsion by Directed Explosive Emulsification
Self‐Propulsion by Directed Explosive Emulsification
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定向爆炸乳化自推进
DOI：
10.1002/adma.202310435
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发表时间：
2024
影响因子：
29.4
通讯作者：
Omar, Ahmad K.
中科院分区：
文献类型：
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作者：
Wu, Xuefei;Xue, Han;Bordia, Gautam;Fink, Zachary;Kim, Paul Y.;Streubel, Robert;Han, Jiale;Helms, Brett A.;Ashby, Paul D.;Omar, Ahmad K.
演示了一种主动液滴系统，该系统被编程为在明确的方向上以特定速度重复自主移动。库仑能通过施加的直流电场存储在带电纳米颗粒表面活性剂的过饱和界面组件中，并且可以根据需要释放。通过增加过饱和组件的刚度来抑制自发乳化。快速移除电场会在爆炸事件中释放储存的能量，推动液滴，其中数千个带电微滴从母液滴表面弹道喷射。通过界面组件的对称性破缺实现定向喷射，并且液滴一侧的微滴羽流的组合相互作用力将液滴推动距离为其尺寸的数十倍，从而使液滴活跃。推进是自主的、可重复的，并且与纳米颗粒的化学成分无关。纳米颗粒组装体中的对称性破缺控制着微滴的速度和推进方向。这种液滴推进机制将推动软微型机器人技术的发展，建立一种新型的活性物质，并引入用于分区输送的新型车辆。
An active droplet system, programmed to repeatedly move autonomously at a specific velocity in a well‐defined direction, is demonstrated. Coulombic energy is stored in oversaturated interfacial assemblies of charged nanoparticle‐surfactants by an applied DC electric field and can be released on demand. Spontaneous emulsification is suppressed by an increase in the stiffness of the oversaturated assemblies. Rapidly removing the field releases the stored energy in an explosive event that propels the droplet, where thousands of charged microdroplets are ballistically ejected from the surface of the parent droplet. The ejection is made directional by a symmetry breaking of the interfacial assembly, and the combined interaction force of the microdroplet plume on one side of the droplet propels the droplet distances tens of times its size, making the droplet active. The propulsion is autonomous, repeatable, and agnostic to the chemical composition of the nanoparticles. The symmetry‐breaking in the nanoparticle assembly controls the microdroplet velocity and direction of propulsion. This mechanism of droplet propulsion will advance soft micro‐robotics, establishes a new type of active matter, and introduces new vehicles for compartmentalized delivery.