Wetting on nanoporous alumina surface: Transition between Wenzel and Cassie states controlled by surface structure
Wetting on nanoporous alumina surface: Transition between Wenzel and Cassie states controlled by surface structure
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DOI：
10.1021/la801461j
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发表时间：
2008-09-16
期刊：
影响因子：
3.9
通讯作者：
Hou, Wentao
中科院分区：
文献类型：
--
作者：
Ran, Chunbo;Ding, Guqiao;Hou, Wentao
本文报道了有序纳米多孔氧化铝表面结构与润湿状态关系的系统研究。在保持孔间距和深度不变的情况下，通过增加孔径，多孔氧化铝的润湿性从亲水性急剧改变为疏水性。这一现象归因于Wenzel态和Cassie态之间的逐渐转变，通过比较这些多孔氧化铝表面上的润湿行为，实验证明了这一点。此外，在固定的孔间距和直径的表面润湿性与孔深度的关系进行了研究。对于孔径相对较大的多孔氧化铝，随着孔深的增加，也实现了Wenzel态和Cassie态之间的转变。提出了一个毛细压力平衡模型来解释这种独特的结构诱导相变，并讨论了Cassie润湿表面的设计和构造准则。这些结构诱导的Wenzel和Cassie状态之间的转变可以提供进一步的洞察粗糙度诱导的润湿性和实用的指导设计可变的表面可控的润湿性的润湿机制。
This paper reports a systematic study on the relationship between surface structure and wetting state of ordered nanoporous alumina surface. The wettability of the porous alumina is dramatically changed from hydrophilicity to hydrophobicity by increasing the hole diameter, while maintaining the hole interval and depth. This phenomenon is attributed to the gradual transition between Wenzel and Cassie states which was proved experimentally by comparing the wetting behavior on these porous alumina surfaces. Furthermore, the relationship between surface wettability and hole depth at a fixed hole interval and diameter was investigated. For those porous alumina with relatively larger holes in diameter, transition between Wenzel and Cassie states was also achieved with increasing hole depth. A capillary-pressure balance model was proposed to elucidate the unique structure-induced transition, and the criteria for the design and construction of a Cassie wetting surface was discussed. These structure-induced transitions between Wenzel and Cassie states could provide further insight into the wetting mechanism of roughness-induced wettability and practical guides for the design of variable surfaces with controllable wettability.