Brightness of Microtrench Superhydrophobic Surfaces and Visual Detection of Intermediate Wetting States
Brightness of Microtrench Superhydrophobic Surfaces and Visual Detection of Intermediate Wetting States
复制标题
微沟槽超疏水表面的亮度和中间润湿状态的视觉检测
DOI：
10.1021/acs.langmuir.0c03172
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发表时间：
2021
期刊：
影响因子：
3.9
通讯作者：
Kim, Chang-Jin “CJ”
中科院分区：
文献类型：
--
作者：
Yu, Ning;Kiani, Sarina;Xu, Muchen;Kim, Chang-Jin “CJ”
对于水下的超疏水（SHPo）表面，去湿或润湿状态很容易分别通过亮银色的胸甲或缺少胸甲来区分。然而，为了检测两者之间的中间状态，其中水部分侵入表面粗糙度，需要一种特殊的可视化技术。聚焦于平行微沟槽的SHPo表面，并将减阻视为突出的应用，我们（i）表明仅依赖表面亮度可能严重误导润湿状态，（ii）理论化亮度如何由水侵入深度和观察方向确定，（iii）用共聚焦显微镜和CCD相机实验支持该理论，（iv）介绍如何使用从不同角度拍摄的光学图像来估计入侵深度，以及（v）展示如何通过简单观察来检测稍微偏离适当去湿状态的中间状态。所提出的方法将允许监测SHPo沟槽表面，而无需笨重的仪器，特别是用于大样本和现场测试。
For a superhydrophobic (SHPo) surface under water, the dewetted or wetted states are easily distinguishable by the bright silvery plastron or lack of it, respectively. However, to detect an intermediate state between the two, where water partially intrudes the surface roughness, a special visualization technique has been needed. Focusing on SHPo surfaces of parallel microtrenches and considering drag reduction as a prominent application, we (i) show the reliance on surface brightness alone may seriously mislead the wetting state, (ii) theorize how the brightness is determined by water intrusion depth and viewing direction, (iii) support the theory experimentally with confocal microscopy and CCD cameras, (iv) present how to estimate the intrusion depth using optical images taken from different angles, and (v) showcase how to detect intermediate states slightly off the properly dewetted state by simply looking. The proposed method would allow monitoring SHPo trench surfaces without bulky instruments—especially useful for large samples and field tests.