Field-Induced Wettability Gradients for No-Loss Transport of Oil Droplets on Slippery Surfaces
Field-Induced Wettability Gradients for No-Loss Transport of Oil Droplets on Slippery Surfaces
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DOI：
10.1021/acsami.0c06389
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发表时间：
2020-08-26
影响因子：
9.5
通讯作者：
Zhou, Guofu
中科院分区：
文献类型：
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作者：
Tang, Biao;Meng, Chuanzhi;Zhou, Guofu
输送油滴对于广泛的工业和生物医学应用至关重要，但由于大多数固体表面上的大接触角滞后，仍然具有高度挑战性。液体注入的光滑表面具有低滞后接触角，并且如果可以产生足够的润湿性梯度，则是非常有前途的平台。用于产生润湿性梯度的当前策略通常依赖于化学成分或几何结构的工程设计。然而，这些策略在光滑表面上是低效的，因为注入的液体倾向于隐藏化学成分和小尺度几何结构的梯度。另一方面，放大结构将显著地扭曲表面形貌，这在实践中是不希望的。在这项研究中，我们解决了这一挑战，通过引入一个场诱导的润湿性梯度在平坦的光滑表面。通过印刷径向电极阵列，我们可以图案化的电场，诱导梯度接触角。理论分析和实验结果表明，液滴的输运行为可以用无量纲的电子键数来描述。我们的表面能够实现各种类型液滴的无损失运输，我们希望找到重要的应用，如传热，抗污染，微流体和生化分析。
Transporting oil droplets is crucial for a wide range of industrial and biomedical applications but remains highly challenging due to the large contact angle hysteresis on most solid surfaces. A liquid-infused slippery surface has a low hysteresis contact angle and is a highly promising platform if sufficient wettability gradient can be created. Current strategies used to create wettability gradient typically rely on the engineering of the chemical composition or geometrical structure. However, these strategies are inefficient on a slippery surface because the infused liquid tends to conceal the gradient in the chemical composition and small-scale geometrical structure. Magnifying the structure, on the other hand, will significantly distort the surface topography, which is unwanted in practice. In this study, we address this challenge by introducing a field-induced wettability gradient on a flat slippery surface. By printing radial electrodes array, we can pattern the electric field, which induces gradient contact angles. Theoretical analysis and experimental results reveal that the droplet transport behavior can be captured by a nondimensional electric Bond number. Our surface enables no-loss transport of various types of droplets, which we expect to find important applications such as heat transfer, anticontamination, microfluidics, and biochemical analysis.