Slippery Wenzel State
Slippery Wenzel State
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DOI：
10.1021/acsnano.5b04151
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发表时间：
2015-09-01
期刊：
影响因子：
17.1
通讯作者：
Wong, Tak-Sing
中科院分区：
文献类型：
--
作者：
Dai, Xianming;Stogin, Birgitt Boschitsch;Wong, Tak-Sing
提高液滴在粗糙表面上的流动性在工业上具有极大的兴趣，其应用范围从冷凝热传递到水收集到防止结冰和结霜。液滴在粗糙固体表面上的流动性一直与其润湿状态有关。当液滴位于固体纹理的顶部并且空气被困在下面时，它们处于Cassie状态。当液滴覆盖固体纹理时，它们处于Wenzel状态。虽然Cassie状态长期以来一直与高液滴流动性和Wenzel状态与液滴钉扎相关联，但我们的工作通过显示Cassie和Wenzel状态液滴在纳米纹理使能的光滑粗糙表面上可以是高度移动的来挑战这种现有的惯例。我们的表面是通过设计层次化的纳米和微米尺度的纹理和注入液体润滑剂到纳米纹理单独创造一个高度光滑的粗糙表面。我们已经表明，液滴的流动性可以保持即使在Cassie-to-Wenzel过渡。此外，滑温泽尔态的发现使我们能够以迄今为止最高的实验精度评估经典和最近的温泽尔模型的基本极限，这是任何其他传统粗糙表面都无法实现的。结果表明，经典的Wenzel方程（1936）不能预测高润湿性液体在Wenzel态下的润湿行为。
Enhancing the mobility of liquid droplets on rough surfaces is of great interest in industry, with applications ranging from condensation heat transfer to water harvesting to the prevention of icing and frosting. The mobility of a liquid droplet on a rough solid surface has long been associated with its wetting state. When liquid drops are sitting on the top of the solid textures and air is trapped underneath, they are in the Cassie state. When the drops impregnate the solid textures, they are in the Wenzel state. While the Cassie state has long been associated with high droplet mobility and the Wenzel state with droplet pinning, our work challenges this existing convention by showing that both Cassie and Wenzel state droplets can be highly mobile on nanotexture-enabled slippery rough surfaces. Our surfaces were developed by engineering hierachical nano- and microscale textures and infusing liquid lubricant into the nanotextures alone to create a highly slippery rough surface. We have shown that droplet mobility can be maintained even after the Cassie-to-Wenzel transition. Moreover, the discovery of the slippery Wenzel state allows us to assess the fundamental limits of the classical and recent Wenzel models at the highest experimental precision to date, which could not be achieved by any other conventional rough surface. Our results show that the classical Wenzel eq (1936) cannot predict the wetting behaviors of highly wetting liquids in the Wenzel state.