Liquid Marble Coalescence and Triggered Microreaction Driven by Acoustic Levitation

Liquid
marbles show promising potential for application in the microreactor
field. Control of the coalescence between two or among multiple liquid
marbles is critical; however, the successful merging of two isolated
marbles is difficult because of their mechanically robust particle
shells. In this work, the coalescence of multiple liquid marbles was
achieved via acoustic levitation. The dynamic behaviors of the liquid
marbles were monitored by a high-speed camera. Driven by the sound
field, the liquid marbles moved toward each other, collided, and eventually
coalesced into a larger single marble. The underlying mechanisms of
this process were probed via sound field simulation and acoustic radiation
pressure calculation. The results indicated that the pressure gradient
on the liquid marble surface favors the formation of a liquid bridge
between the liquid marbles, resulting in their coalescence. A preliminary
indicator reaction was induced by the coalescence of dual liquid marbles,
which suggests that expected chemical reactions can be successfully
triggered with multiple reagents contained in isolated liquid marbles
via acoustic levitation.

液弹（liquid marbles）在微反应器领域展现出可观的应用潜力。调控两个或多个液弹之间的聚结过程至关重要；然而，由于液弹表面具有机械强度较高的颗粒壳层，实现两个独立液弹的成功融合颇具挑战。本研究通过声悬浮技术实现了多个液弹的聚结，并借助高速相机对液弹的动态行为进行了实时监测。在声场的驱动下，液弹相互靠近、碰撞，最终融合为一颗更大的单液弹。本研究通过声场模拟与声辐射压力计算，对该过程的内在作用机理进行了探究。结果表明，液弹表面的压力梯度有利于液弹间液桥的形成，进而促成二者的聚结。通过双液弹的聚结可引发初步的指示反应，这意味着借助声悬浮技术，利用独立液弹所携带的多种试剂，能够成功触发预期的化学反应。