Not spreading in reverse: The dewetting of a liquid film into a single drop.
Not spreading in reverse: The dewetting of a liquid film into a single drop.
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DOI：
10.1126/sciadv.1600183
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发表时间：
2016-09
期刊：
影响因子：
13.6
通讯作者：
McHale G
中科院分区：
文献类型：
--
作者：
Edwards AM;Ledesma-Aguilar R;Newton MI;Brown CV;McHale G
去湿膜不是扩散液滴的时间反转。润湿和去湿是液体在固体表面上运动的两种基本模式。它们对于生物学、化学和工程过程至关重要，例如干燥、涂层和润滑。然而，最近的进展润湿，这导致了新的领域，如超疏水性和液体大理石，还没有匹配的去湿。一个重要的问题是无法研究一个均匀的膜去湿从非润湿表面到一个单一的宏观液滴的模型系统，一个障碍，不存在的反向润湿过程的液滴扩散成膜。我们报告的去湿的dielectric诱导膜成一个单一的平衡液滴。出现的图片的完整的去湿动力学是一个初始的制度，其中液体边缘后退以恒定的速度和恒定的动态接触角，其次是一个相对较短的指数松弛的球冠形状。这与反向润湿过程形成鲜明对比，在反向润湿过程中，扩散的液滴遵循一系列平滑的球冠形状。互补的数值模拟和流体动力学模型揭示了平衡接触角驱动的局部去湿机制，其中接触线滑移主导去湿动力学。我们的结论可以用来理解各种各样的过程，涉及液体去湿，如下降反弹，冷凝和蒸发。在克服障碍，研究单一的膜-液滴去湿，我们的研究结果提供了新的方法，流体操纵和使用的去湿，如诱导膜规定的初始形状和滑动控制的液体回缩。
Dewetting films are not the time reversal of spreading droplets. Wetting and dewetting are both fundamental modes of motion of liquids on solid surfaces. They are critically important for processes in biology, chemistry, and engineering, such as drying, coating, and lubrication. However, recent progress in wetting, which has led to new fields such as superhydrophobicity and liquid marbles, has not been matched by dewetting. A significant problem has been the inability to study the model system of a uniform film dewetting from a nonwetting surface to a single macroscopic droplet—a barrier that does not exist for the reverse wetting process of a droplet spreading into a film. We report the dewetting of a dielectrophoresis-induced film into a single equilibrium droplet. The emergent picture of the full dewetting dynamics is of an initial regime, where a liquid rim recedes at constant speed and constant dynamic contact angle, followed by a relatively short exponential relaxation of a spherical cap shape. This sharply contrasts with the reverse wetting process, where a spreading droplet follows a smooth sequence of spherical cap shapes. Complementary numerical simulations and a hydrodynamic model reveal a local dewetting mechanism driven by the equilibrium contact angle, where contact line slip dominates the dewetting dynamics. Our conclusions can be used to understand a wide variety of processes involving liquid dewetting, such as drop rebound, condensation, and evaporation. In overcoming the barrier to studying single film-to-droplet dewetting, our results provide new approaches to fluid manipulation and uses of dewetting, such as inducing films of prescribed initial shapes and slip-controlled liquid retraction.
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影响因子：
6.3
作者：
Desplat, JC;Pagonabarraga, I;Bladon, P
通讯作者：
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影响因子：
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作者：
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DOI：
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影响因子：
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作者：
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通讯作者：
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影响因子：
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作者：
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通讯作者：
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