Thermally induced delay and reversal of liquid film dewetting on chemically patterned surfaces.
Thermally induced delay and reversal of liquid film dewetting on chemically patterned surfaces.
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DOI：
10.1016/j.jcis.2013.06.035
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发表时间：
2013-10
影响因子：
9.9
通讯作者：
Sreeram K. Kalpathy;L. Francis;Satish Kumar
中科院分区：
文献类型：
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作者：
Sreeram K. Kalpathy;L. Francis;Satish Kumar
置于固体基底上的薄液膜从下方加热或冷却，经历表面张力梯度，这导致马兰戈尼流。我们探索这样的膜在化学图案化的基板上的行为，该基板驱动膜去湿，以确定如何设计表面图案化和施加的温度梯度来影响薄膜涂层的行为。一个非线性偏微分方程的膜高度润滑理论的基础上数值求解的问题参数范围很广。均匀冷却的基板被发现显着延迟去湿，是由润湿性梯度驱动。均匀加热加速去湿，但可能破坏表面图案化所施加的近乎完美的模板。然而，局部加热和冷却一起可以加速去湿，同时保持模板质量。局部加热和冷却也可以用于将液体驱动到在没有加热的情况下会去湿的区域上。总体而言，这些结果表明，施加的温度梯度可以显着影响去湿驱动的表面图案化，并建议在微流体装置中的空间图案化的薄膜涂层和流动控制的创建策略。
A thin liquid film resting on a solid substrate that is heated or cooled from below experiences surface tension gradients, which lead to Marangoni flows. We explore the behavior of such a film on a chemically patterned substrate which drives film dewetting in order to determine how surface patterning and applied temperature gradients can be designed to influence the behavior of thin-film coatings. A nonlinear partial differential equation for the film height based on lubrication theory is solved numerically for a broad range of problem parameters. Uniform cooling of the substrate is found to significantly delay dewetting that is driven by wettability gradients. Uniform heating speeds up dewetting but can destroy the near-perfect templating imposed by the surface patterning. However, localized heating and cooling together can accelerate dewetting while maintaining templating quality. Localized heating and cooling can also be used to drive liquid onto areas that it would dewet from in the absence of heating. Overall, these results indicate that applied temperature gradients can significantly influence dewetting driven by surface patterning, and suggest strategies for the creation of spatially patterned thin-film coatings and flow control in microfluidic devices.