Why Condensate Drops Can Spontaneously Move Away on Some Superhydrophobic Surfaces but Not on Others
Why Condensate Drops Can Spontaneously Move Away on Some Superhydrophobic Surfaces but Not on Others
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DOI：
10.1021/am301767k
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发表时间：
2012-12-01
影响因子：
9.5
通讯作者：
Yao, Shuhuai
中科院分区：
文献类型：
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作者：
Feng, Jie;Pang, Yichuan;Yao, Shuhuai
超疏水表面上凝聚诱导的液滴运动因其广泛的应用前景而受到越来越多的关注。然而，自发运动的微观机制还没有得到深入的讨论。在这项研究中，我们制备了两种类型的超疏水铜表面与剑麻样纳米取向结构和脱叶样纳米片结构，通过不同的湿化学氧化工艺，然后相同的氟化处理。以荷叶和蝴蝶翅膀为对照样品，利用光学显微镜研究了这4种SHS上冷凝液滴在常温下的自发运动现象。结果表明，在4种自蔓延合成体系中，只有具有剑麻状纳米颗粒结构的超疏水铜表面表现出明显的冷凝液滴自发运动，尤其是在相对湿度较高的条件下.自发运动的微观机制进行了讨论，在不同的纳米结构上的冷凝液滴的状态。这表明，凝聚液滴在聚结之前的瞬时Cassie状态在决定聚结液滴是否离开中起关键作用，而只有具有足够小的Wenzel粗糙度参数r（至少
The coalesce-induced condensate drop motion on some superhydrophobic surfaces (SHSs) has attracted increasing attention because of its wide potential applications. However, microscopic mechanism of spontaneous motion has not been discussed thoroughly. In this study, we fabricated two types of superhydrophobic copper surfaces with sisal-like nanoribbon structures and defoliation-like nanosheet structures by different wet chemical oxidation process and followed by same fluorization treatment. With lotus leaf and butterfly wing as control samples, the spontaneous motion phenomenon of condensate drops on these four kinds of SHSs was investigated by using optical microscope under ambient conditions. The results showed that among all four types of SHSs, only superhydrophobic copper surfaces with sisal-like nanoribbon structures showed obvious spontaneous motion of condensate drops, especially when the relative humidity was higher. The microscopic mechanism of spontaneous motion was discussed in relation to the states of condensate drops on different nanostructures. It shows that the instantaneous Cassie state of condensed droplets prior to coalescence plays a key role in determining whether the coalesced drop departs, whereas only SHS possessing nanostructures with small enough Wenzel roughness parameter r (at least