Lin Kejun, Zang Duyang, Geng Xingguo, Chen Zhen
Functional Soft Matter & Materials Group, Key Laboratory of Space Applied Physics and Chemistry of Ministry of Education, School of Science, Northwestern Polytechnical University, 710129, Xi'an, China.
NPU-UM II joint Lab of Soft Matter, School of Science, Northwestern Polytechnical University, 710129, Xi'an, China.
Eur Phys J E Soft Matter. 2016 Feb;39(2):15. doi: 10.1140/epje/i2016-16015-8. Epub 2016 Feb 25.
We have studied the wetting behaviors of surfaces with a single micro-scale structure and a double micro/nano hierarchical structure, respectively. We have found the delayed wetting phenomenon on the single micro scale surface, which indicates that the wetting state transits from the initial Cassie state to the Cassie impregnating one. Furthermore, the droplet rebound becomes incomplete on the single micro scale surface when the impact velocity exceeds a critical value. On the contrary, complete rebound can still be observed when impacting on the micro/nano hierarchical structure. We proposed that, under static deposition the wetting transition occurs though the contact line depinning mechanism, whereas it occurs via sagging mechanism under a dynamic impact. Our results may be helpful for the understanding of superhydrophobicity and the wetting transition on complex structures.
我们分别研究了具有单一微尺度结构和双微/纳分级结构表面的润湿行为。我们在单一微尺度表面发现了延迟润湿现象，这表明润湿状态从初始的 Cassie 状态转变为 Cassie 浸渍状态。此外，当冲击速度超过临界值时，液滴在单一微尺度表面上的反弹变得不完全。相反，当撞击微/纳分级结构时，仍可观察到完全反弹。我们提出，在静态沉积下，润湿转变通过接触线脱钉机制发生，而在动态冲击下则通过下垂机制发生。我们的结果可能有助于理解复杂结构上的超疏水性和润湿转变。
