Matsuo Muneyuki, Hashishita Hiromi, Tanaka Shinpei, Nakata Satoshi
Graduate School of Integrated Sciences for Life, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526, Japan.
Graduate School of Advanced Science and Engineering, Hiroshima University, 1-7-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8521, Japan.
Langmuir. 2023 Feb 7;39(5):2073-2079. doi: 10.1021/acs.langmuir.2c03344. Epub 2023 Jan 24.
Subsequent synthesis and detection using droplets as microreactors have shown promise in the development of novel materials and drugs because microreactors enable small-scale synthesis and detection of covalent/non-covalent intermolecular interactions. Self-organization exhibited by autonomous droplets under non-equilibrium conditions is beneficial for manipulating the sequentiality and selectivity of droplet coalescence because expensive equipment or elaborate techniques are not required with the autonomy of droplets. However, to our knowledge, selective coalescence caused by the collective motion of self-propelled droplets has not been demonstrated in inanimate systems. Here, we report sequentially selective coalescence based on the dynamic collective pattern of self-propelled droplets composed of ethyl salicylate (ES) or butyl salicylate (BS). When ES and BS droplets were placed on an aqueous sodium dodecyl sulfate (SDS) solution, the collective motion of droplets resulted in three stages of selective coalescence on the time development. Initially, coalescence was observed only between different types of self-propelled droplets. Subsequently, the formed droplets selectively coalesced with ES droplets. Finally, mature droplets merged with BS droplets. The sequentially selective coalescence was discussed from the dynamic pattern formation of swarming droplets and the collapse of the SDS monolayer at the o/w interface caused by the difference in Laplace pressure and the interfacial instability at the contact point between droplets. Thus, this study formulates a strategy of sequentially selective coalescence of droplets via the collective motion of non-identical self-propelled droplets, promoting a new type of powerful and efficient automation technology based on an autonomous inanimate manner of spatiotemporal pattern formation under non-equilibrium conditions for the droplet manipulation.
随后，将液滴用作微反应器进行合成和检测在新型材料和药物的开发中显示出了前景，因为微反应器能够实现小规模合成以及对共价/非共价分子间相互作用的检测。在非平衡条件下自主液滴所展现出的自组织特性，有利于操控液滴聚结的顺序性和选择性，因为液滴的自主性使得无需昂贵的设备或复杂的技术。然而，据我们所知，在无生命系统中尚未证明由自驱动液滴的集体运动引起的选择性聚结。在此，我们报告了基于由水杨酸乙酯（ES）或水杨酸丁酯（BS）组成的自驱动液滴的动态集体模式的顺序选择性聚结。当将ES和BS液滴放置在十二烷基硫酸钠（SDS）水溶液上时，液滴的集体运动在时间发展上导致了三个阶段的选择性聚结。最初，仅在不同类型的自驱动液滴之间观察到聚结。随后，形成的液滴与ES液滴选择性地聚结。最后，成熟的液滴与BS液滴合并。从聚集液滴的动态模式形成以及由拉普拉斯压力差异和液滴间接触点处的界面不稳定性导致的o/w界面处SDS单层的崩塌方面讨论了顺序选择性聚结。因此，本研究制定了一种通过不同的自驱动液滴的集体运动实现液滴顺序选择性聚结的策略，促进了一种基于非平衡条件下自主无生命的时空模式形成方式的新型强大且高效的自动化技术，用于液滴操控。
