Wettability of Microstructured Hydrophobic Sol-Gel Coatings
Wettability of Microstructured Hydrophobic Sol-Gel Coatings
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DOI：
10.1023/a:1020779011844
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发表时间：
2003
影响因子：
2.5
通讯作者：
S. Pilotek;H. Schmidt
中科院分区：
文献类型：
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作者：
S. Pilotek;H. Schmidt
在疏水表面上形成适当的表面图案导致其润湿性的一般变化，并且接触角显著增加。这种涂层具有很大的技术意义，特别是如果涉及水介质以防止冰粘附。由于这个原因，各种含氟纳米复合涂层已开发出溶胶-凝胶处理。这些疏水表面的形态已被控制，通过改变二氧化硅颗粒的大小，聚集度和浓度的含量。润湿性通过测量对水的动态接触角来表征。不同润湿性状态的完整范围是可获得的，即光滑表面（低前进接触角和前进与后退接触角之间的滞后）、Wenzel状态内的表面（高前进接触角和滞后）和超疏水表面（高前进接触角和低滞后）。润湿性与使用轮廓仪或AFM测定的表面粗糙度相关。超疏水表面的润湿性极大地依赖于液体的表面张力。通过比较光滑表面和超疏水表面的倾斜角θ t，确定了临界表面张力γ，其中θt（光滑表面）= θt（微结构表面）。微结构化表面提供更好的液体流出γlg> γc> 55 mN·m−1。
The formation of appropriate surface patterns on hydrophobic surfaces leads to a general change in their wettability and the contact angle increases substantially. Such coatings are of great technical interest, especially if aqueous media are concerned as in the prevention of ice-adhesion. For this reason various fluorine containing nanocomposite coatings have been developed by sol-gel processing.The morphology of these hydrophobic surfaces has been controlled by varying the content of silica particles regarding size, degree of aggregation, and concentration. The wettability is characterized by the measurement of dynamic contact angles against water. The complete range of different wettability regimes is accessible, i.e. smooth surfaces (both low advancing contact angle and hysteresis between advancing and receding contact angle), surfaces within the Wenzel regime (high advancing contact angle and hysteresis), and superhydrophobic surfaces (high advancing contact angle and low hysteresis). The wettability is correlated with the surface roughness as determined using a profilometer or AFM.The wettability of superhydrophobic surfaces is greatly dependent on the surface tension of the liquid. By comparison of the tiltangle θtof a smooth and a superhydrophobic surface, a critical surface tension γcis identified, where θt(smooth surface) = θt(microstructured surface). The microstructured surface provides a better run-off of liquids γlg> γc≈ 55 mN·m−1.