Superhydrophobicity of Biological and Technical Surfaces under Moisture Condensation: Stability in Relation to Surface Structure
Superhydrophobicity of Biological and Technical Surfaces under Moisture Condensation: Stability in Relation to Surface Structure
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DOI：
10.1021/la802351h
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发表时间：
2008-12-02
期刊：
影响因子：
3.9
通讯作者：
Barthlott, Wilhelm
中科院分区：
文献类型：
--
作者：
Mockenhaupt, Bernd;Ensikat, Hans-Juergen;Barthlott, Wilhelm
比较了八种植物和四种技术表面在水冷凝方面的超疏水特性的稳定性。在将环境温度（20摄氏度）的水滴施加到冷却的表面上之后测量接触角和滑动角。由于液滴和表面之间的温差，从液滴蒸发的水在冷却的样品上冷凝，在液滴附近形成“卫星液滴”。表面冷却至15、10和5摄氏度显示出超疏水性逐渐降低。这种降低取决于样品的比表面结构。最少的减少被发现在分级结构的表面与粗糙的微观结构和亚微米尺寸的结构，类似于荷叶的组合。进行了甘油液滴的对照实验，该实验显示没有蒸发，因此没有冷凝，以验证水的影响是由液滴的冷凝（二次冷凝）引起的。此外，超疏水性能冷凝后的冷却表面从潮湿的环境中10分钟进行了检查。在此之后，表面被球形水滴覆盖，但大多数样品保留了其超疏水性。再次，防水性能的最佳稳定性被发现在类似于荷叶的分级结构的表面上。
The stability of superhydrophobic properties of eight plants and four technical surfaces in respect to water condensation has been compared. Contact and sliding angles were measured after application of water drops of ambient temperature (20 degrees C) onto cooled surfaces. Water evaporating from the drops condensed, due to the temperature difference between the drops and the surface, on the cooled samples, forming "satellite droplets" in the vicinity of the drops. Surface cooling to 15, 10, and 5 degrees C showed a gradual decrease of superhydrophobicity. The decrease was dependent on the specific surface architecture of the sample. The least decrease was found on hierarchically structured surfaces with a combination of a coarse microstructure and submicrometer-sized structures, similar to that of the Lotus leaf. Control experiments with glycerol droplets, which show no evaporation, and thus no condensation, were carried out to verify that the effects with water were caused by condensation from the drop (secondary condensation). Furthermore, the superhydrophobic properties after condensation on cooled surfaces from a humid environment for 10 min were examined. After this period, the surfaces were covered with spherical water droplets, but most samples retained their superhydrophobicity. Again, the best stability of the water-repellent properties was found on hierarchically structured surfaces similar to that of the Lotus leaf.