Wetting of rough three-dimensional superhydrophobic surfaces
Wetting of rough three-dimensional superhydrophobic surfaces
复制标题
粗糙三维超疏水表面的润湿
DOI：
10.1007/s00542-005-0067-x
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发表时间：
2006
期刊：
影响因子：
--
通讯作者：
B. Bhushan
中科院分区：
文献类型：
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作者：
Michael Nosonovsky;B. Bhushan
研究了粗糙三维周期表面的润湿问题。由于接触面积和气囊作用的不同，粗糙表面(θ)和光滑表面(θ0)液体的接触角也不同。对于非润湿液体(θ0>；π/2)，接触角随粗糙度增加而增大，并可能接近超疏水表面(π)的值。对于高θ0，可能形成均匀的固液界面，以及在粗糙表面的山谷处带有气囊的复合固-液-气界面。这两个界面对应于不同的平衡状态，并导致不同的θ。介绍了一种基于概率的方法来处理多个平衡态和计算θ。研究还发现，增大液滴尺寸与增大粗糙度周期(粗糙度大小)具有相同的效果。对于较大的液滴和较大的粗糙度，复合界面的可能性较小。对于涉及通道粗糙壁附近液体传输的应用，提出了将非润湿液体液滴与润湿液体中的气泡进行类比。为了增加气泡的迁移率，应尽量减小接触角和接触角滞后。提出了超疏水表面设计的实用建议。
Wetting of rough three-dimensional periodic surfaces is studied. The contact angle of liquid with a rough surface (θ) is different from that with a smooth surface (θ0) due to the difference in the contact area and effect of the air pockets. For non-wetting liquids (θ0>π/2), the contact angle increases with roughness and may approach the value of π (superhydrophobic surface). For high θ0, a homogeneous solid-liquid interface, as well as a composite solid-liquid-air interface with air pockets at the valleys of rough surface are possible. These two interfaces correspond to different states of equilibrium and result in different θ. A probability-based approach is introduced to handle the multiple states of equilibrium and to calculate θ. It is found also that increasing droplet size has the same effect as increasing period of roughness (size of asperities). For larger droplets and for larger asperities, the composite interface is less likely. For applications involving liquid’s transport near rough walls of a channel, an analogy between a droplet of non-wetting liquid and a gas bubble in wetting liquid is proposed. In order to increase bubbles mobility, the contact angle and the contact angle hysteresis should be minimized. Practical recommendations for design of superhydrophobic surfaces are formulated.