Drop impact onto polarized dielectric surface for controlled coating
Drop impact onto polarized dielectric surface for controlled coating
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DOI：
10.1063/5.0054077
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发表时间：
2021-06
影响因子：
4.6
通讯作者：
A. Sankaran;Jingwei Wu;R. Granda;Vitaliy Yurkiv;F. Mashayek;A. Yarin
中科院分区：
文献类型：
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作者：
A. Sankaran;Jingwei Wu;R. Granda;Vitaliy Yurkiv;F. Mashayek;A. Yarin
通过电介质润湿(EWOD)来控制表面润湿性是主动增强表面润湿性的最有效方法之一。本文实验研究了电极埋入(或对准并附着)电介质表面时，液滴撞击介质表面的电流体动力学。研究了不同液体(水、正丁醇和机油)对不同基材(拉伸聚四氟乙烯、聚四氟乙烯薄膜和聚丙烯)的液滴影响。详细研究了水滴对拉伸聚四氟乙烯和非拉伸聚四氟乙烯表面的影响。水滴撞击实验结果表明，外加电场可以显著增强水滴在非湿表面上的扩散。特别是，水滴的回弹可以被电力抑制。此外，还探讨了碳氢液体在电场作用下的碰撞动力学和扩散规律。在增强扩散的同时，外加电场也部分抑制了飞溅现象。此外，对水滴的实验结果与Cahn−Stokes(CHNS)的静态接触角和液滴撞击动力学的模拟结果进行了比较，水滴的模拟结果与实验结果基本一致。这项研究表明，电介质润湿技术在涂层和喷涂技术中具有很大的前景。
Control of surface wettability by means of electrowetting-on-dielectric (EWOD) is among the most effective methods of active enhancement of surface wettability. Here, electrohydrodynamics of drop impact onto a dielectric surface with electrodes embedded in the dielectric (or aligned and attached to it) is experimentally investigated. Drop impact of different liquids (water, n-butanol, and motor oil) onto different substrates (stretched Teflon, parafilm, and polypropylene) is studied. Water drop impact onto stretched Teflon (the only Teflon which revealed significant electrowetting) and un-stretched parafilm surfaces is studied in detail. The results for water drop impact indicate that drop spreading on such non-wettable surfaces can be significantly enhanced by the electric field application. In particular, water drop rebound can be suppressed by the electric force. Furthermore, impact dynamics and spreading of hydrocarbon liquids with electric field are explored. Partial suppression of splash phenomena was also observed with the application of the electric field in addition to enhancement of spreading. In addition, the experimental results for water drops are compared with the Cahn−Hilliard−Navier−Stokes (CHNS) simulations for static contact angles and drop impact dynamics, and the results are in close agreement for water drops. This study demonstrates that electrowetting-on-dielectric holds great promise for coating and spraying technologies.