Biocolloid and Fluid Physics Group, Applied Physics Department, Faculty of Sciences, University of Granada, Campus de Fuentenueva s/n, 18071 Granada, Spain.
Biocolloid and Fluid Physics Group, Applied Physics Department, Faculty of Sciences, University of Granada, Campus de Fuentenueva s/n, 18071 Granada, Spain.
J Colloid Interface Sci. 2017 Dec 15;508:129-136. doi: 10.1016/j.jcis.2017.08.032. Epub 2017 Aug 12.
The analysis of wetting properties of superhydrophobic surfaces may be a difficult task due to the restless behavior of drops on this type of surfaces and the limitations of goniometry for high contact angles. A method to validate the performance of superhydrophobic surfaces, rather than standard goniometry, is required. In this work, we used bouncing drop dynamics as a useful tool to predict the water repellency of different superhydrophobic surfaces. From bouncing drop experiments conducted over a wide range of superhydrophobic surfaces, we found that those surfaces with a proper roughness degree and homogeneous chemical composition showed higher water-repellency. We also conducted a drop condensation study at saturating conditions aimed to determine whether there is direct correlation between water repellency and condensation delay. We found that the drop condensation process is strongly related to the surface topography, as well as the intrinsic wettability. The condensation is promoted on rough surfaces but it is delayed on intrinsically hydrophobic surfaces. However, the differences found in condensation delay between the superhydrophobic surfaces explored in this study cannot be justified by their chemical homogeneity nor their efficiency as water repellent surfaces, separately.
超疏水表面的润湿性分析可能是一项艰巨的任务，因为在这种类型的表面上液滴的行为不稳定，以及接触角法在高接触角时的局限性。需要一种方法来验证超疏水表面的性能，而不是标准的接触角法。在这项工作中，我们使用弹跳液滴动力学作为一种有用的工具来预测不同超疏水表面的疏水性。通过在广泛的超疏水表面上进行弹跳液滴实验，我们发现那些具有适当粗糙度和均匀化学成分的表面表现出更高的疏水性。我们还进行了在饱和条件下的液滴凝结研究，旨在确定疏水性和凝结延迟之间是否存在直接关系。我们发现，液滴凝结过程与表面形貌以及固有润湿性密切相关。在粗糙表面上促进凝结，但在固有疏水性表面上延迟凝结。然而，在这项研究中探索的超疏水表面之间的凝结延迟差异不能仅仅通过它们的化学均匀性或作为疏水性表面的效率来解释。
