Drop Impact upon Micro- and Nanostructured Superhydrophobic Surfaces
Drop Impact upon Micro- and Nanostructured Superhydrophobic Surfaces
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DOI：
10.1021/la900330q
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发表时间：
2009-10-20
期刊：
影响因子：
3.9
通讯作者：
Lohse, Detlef
中科院分区：
文献类型：
--
作者：
Tsai, Peichun;Pacheco, Sergio;Lohse, Detlef
我们实验研究了不同的超疏水表面上的跌落冲击动力学，包括规则的聚合物微图案和粗糙的碳纳米纤维，具有相似的静态接触角。主要控制参数为韦伯数和表面粗糙度。在较小的We，即较小的冲击速度下，两种类型的衬底的冲击演变相似，表现为Fakir状态，完全反弹，部分反弹，气泡捕获，喷射和粘性振动水球。总的来说，飞溅的冲击形成了几个卫星液滴，这在多尺度粗糙的碳纳米纤维丛林中更为明显。结果表明，当We小于或接近120时，纳米尺度的多尺度表面粗糙度对撞击事件的影响较小，而当We大于或接近120时，多尺度表面粗糙度对撞击事件的影响非常重要。最后，我们发现环境空气压力的影响可以忽略不计，在探索的参数范围内，我们小于或接近150。
We experimentally investigate drop impact dynamics onto different superhydrophobic surfaces, consisting of regular polymeric micropatterns and rough carbon nanofibers, with similar static contact angles. The main control parameters are the Weber number We and the roughness of the surface. At small We, i.e., small impact velocity, the impact evolutions are similar for both types of substrates, exhibiting Fakir state, complete bouncing, partial rebouncing, trapping of an air bubble, jetting, and sticky vibrating water balls. At large We, splashing impacts emerge forming several satellite droplets, which arc more pronounced for the multiscale rough carbon nanofiber jungles. The results imply that the multiscale surface roughness at nanoscale plays a minor role in the impact events for small We less than or similar to 120 but ail important one for large We greater than or similar to 120. Finally, we find the effect of ambient air pressure to be negligible in the explored parameter regime We less than or similar to 150.