Wang Qianbin, Yao Xi, Liu Huan, Quéré David, Jiang Lei
Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry and Environment, Beihang University, Beijing 100191, People's Republic of China;
Department of Biological Sciences, City University of Hong Kong, Hong Kong;
Proc Natl Acad Sci U S A. 2015 Jul 28;112(30):9247-52. doi: 10.1073/pnas.1506874112. Epub 2015 Jul 13.
The ability to control drops and their movements on phobic surfaces is important in printing or patterning, microfluidic devices, and water-repellent materials. These materials are always micro-/nanotextured, and a natural limitation of repellency occurs when drops are small enough (as in a dew) to get trapped in the texture. This leads to sticky Wenzel states and destroys the superhydrophobicity of the material. Here, we show that droplets of volume ranging from femtoliter (fL) to microliter (μL) can be self-removed from the legs of water striders. These legs consist of arrays of inclined tapered setae decorated by quasi-helical nanogrooves. The different characteristics of this unique texture are successively exploited as water condenses, starting from self-penetration and sweeping effect along individual cones, to elastic expulsion between flexible setae, followed by removal at the anisotropic leg surface. We envision that this antifogging effect at a very small scale could inspire the design of novel applicable robust water-repellent materials for many practical applications.
在印刷或图案制作、微流控设备及疏水材料中,控制液滴及其在憎水表面上的运动能力至关重要。这些材料通常具有微/纳米纹理,当液滴小到足以被困在纹理中(如露珠)时,疏水性就会出现自然限制。这会导致粘性的文泽尔状态并破坏材料的超疏水性。在此,我们展示了体积从飞升至微升的液滴能够从水黾腿部自行去除。这些腿部由倾斜的锥形刚毛阵列组成,表面饰有准螺旋纳米凹槽。随着水的凝结,这种独特纹理的不同特性被依次利用,从沿着单个锥体的自穿透和清扫效应,到柔性刚毛之间的弹性排出,再到在各向异性腿部表面的去除。我们设想,这种在非常小尺度上的防雾效果能够启发许多实际应用中新型适用的坚固疏水材料的设计。