Contact-angle hysteresis on super-hydrophobic surfaces
Contact-angle hysteresis on super-hydrophobic surfaces
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DOI：
10.1021/la0486584
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发表时间：
2004-11-09
期刊：
影响因子：
3.9
通讯作者：
Newton, MI
中科院分区：
文献类型：
--
作者：
McHale, G;Shirtcliffe, NJ;Newton, MI
从理论上讨论了粗糙或织构表面上接触角的扰动与平衡接触角的超疏水增强之间的关系。两种模式被认为是。在第一种（Wenzel）情况下，超疏水表面具有非常高的接触角，并且液滴完全接触其所停留的表面。在第二种（Cassie-Baxter）情况下，超疏水表面具有非常高的接触角，但液滴桥接表面突起。理论处理强调接触角放大或衰减的概念，并区分由于粗糙化或纹理化表面而导致的接触角增加和对所得接触角的扰动。该理论适用于预测接触角滞后粗糙表面上的光滑表面上观察到的滞后，因此是相关的倾斜表面上的液滴的滚降角预测。该理论定量地预测了一个“粘性”的表面Wenzel型表面和一个“滑”的表面Cassie-Baxter型表面。
The relationship between perturbations to contact angles on a rough or textured surface and the superhydrophobic enhancement of the equilibrium contact angle is discussed theoretically. Two models are considered. In the first (Wenzel) case, the super-hydrophobic surface has a very high contact angle and the droplet completely contacts the surface upon which it rests. In the second (Cassie-Baxter) case, the super-hydrophobic surface has a very high contact angle, but the droplet bridges across surface protrusions. The theoretical treatment emphasizes the concept of contact-angle amplification or attenuation and distinguishes between the increases in contact angles due to roughening or texturing surfaces and perturbations to the resulting contact angles. The theory is applied to predicting contact-angle hysteresis on rough surfaces from the hysteresis observable on smooth surfaces and is therefore relevant to predicting roll-off angles for droplets on tilted surfaces. The theory quantitatively predicts a "sticky" surface for Wenzel-type surfaces and a "slippy" surface for Cassie-Baxter-type surfaces.