Mechanisms of superhydrophobicity on hydrophilic substrates
Mechanisms of superhydrophobicity on hydrophilic substrates
复制标题
亲水基材的超疏水性机制
DOI：
10.1088/0953-8984/19/35/356002
复制
发表时间：
2007-09-05
影响因子：
2.7
通讯作者：
Yu, Shou-Wen
中科院分区：
文献类型：
--
作者：
Liu, Jian-Lin;Feng, Xi-Qiao;Yu, Shou-Wen
固体表面微结构对超疏水表面的形成起着重要作用。本文从几何和能量的角度研究了粗糙衬底上的Cassie-Baxter模型和Wenzel模型。结果表明，如果正弦衬底上液滴下的空气向大气开放，则只有在衬底疏水的情况下才会存在超疏水状态，微结构的几何参数对润湿行为有很大影响。本发明涉及两种可能导致亲水性衬底的超疏水特性的机制。首先，对于封闭或密封的微结构(如蜂窝结构)，液滴下方的滞留空气产生的负拉普拉斯压差可以保持液/气界面的平衡。其次，满足一定几何条件的表面结构的某些特殊拓扑结构也可能导致Cassie-Baxter态的形成，即使这些微结构是开放的。因此，某些表面形态可以被设计成在亲水表面上获得超疏水性能。本研究还有助于理解在实验和自然界中观察到的一些超疏水现象。
Surface microstructures of solids play a significant role in producing superhydrophobic surfaces. In the present paper, the Cassie-Baxter and Wenzel models on a rough substrate are examined from the viewpoints of geometry and energy. The result shows that if the air beneath a droplet on a sinusoidal substrate is open to the atmosphere, the superhydrophobic state can exist only when the substrate is hydrophobic, and that the geometric parameters of the microstructure have a great influence on the wetting behavior. Two mechanisms that may lead to a superhydrophobic property from a hydrophilic substrate are addressed. Firstly, for closed or airproof microstructures (e. g. honeycomb structures), a negative Laplace pressure difference caused by the trapped air under the drop can keep the balance of the liquid/vapor interface. Secondly, some special topologies of surface structures satisfying a certain geometric condition may also lead to the formation of a Cassie-Baxter state even if the microstructures are open to the air. Therefore, some surface morphologies may be designed to obtain superhydrophobic properties on hydrophilic surfaces. The present study is also helpful to understand some superhydrophobic phenomena observed in experiments and in nature.