Electric field induced reversible spreading of droplets into films on lubricant impregnated surfaces
Electric field induced reversible spreading of droplets into films on lubricant impregnated surfaces
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DOI：
10.1063/1.4978859
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发表时间：
2017-03-20
影响因子：
4
通讯作者：
Newton, Michael I.
中科院分区：
文献类型：
--
作者：
Brabcova, Zuzana;McHale, Glen;Newton, Michael I.
电场可以用来迫使液滴在施加电压的情况下润湿固体表面。然而，显著的滞后通常与接触线上的钉扎力有关。在这里，我们报告了接触线完全可移动的润滑剂浸渍表面(也称为光滑的液体浸入的多孔表面)上，液滴在空气中强制扩散和随后回缩到液膜中的情况。我们首先确认，我们实现了完全消除液滴在饱和电压以上的电润湿的滞后。然后，我们展示了接触角滞后可以降低到4度以下，同时保留了使用液体介电(介湿)局部界面将液滴完全扩散到液膜中的能力。在这两种情况下，我们发现接触角的余弦与外加电压成二次关系，这与以前的理论预期是一致的。因此，我们的工作表明，完全可逆的扩散包括广泛的部分润湿液滴状态和薄膜状态，可以在空气中以可控的方式实现，滞后程度非常低。(C)2017年作者(S)。
Electric fields can be used to force a droplet to wet a solid surface using an applied voltage. However, significant hysteresis usually occurs associated with pinning forces at the contact line. Here, we report the forced spreading and subsequent retraction of droplets into liquid films in air on lubricant impregnated surfaces (also known as slippery liquid infused porous surfaces) where the contact line is completely mobile. We first confirm that we achieve a complete removal of hysteresis for the electrowetting of droplets above the saturation voltage. We then show that contact angle hysteresis can be reduced to less than 4 degrees whilst retaining the ability to fully spread a droplet into a liquid film using an interface localized from liquid dielectrophoresis (dielectrowetting). In both cases, we find that the cosine of the contact angle has a quadratic dependence on applied voltage, consistent with previous theoretical expectations. Thus, our work demonstrates that fully reversible spreading encompassing a wide range of partial wetting droplet states and a film state can be achieved in air in a controllable manner with very low levels of hysteresis. (C) 2017 Author(s).