表面微观结构对液滴浸润的影响特性.doc

文档介绍：
表面微观结构对液滴浸润的影响特性#
贺吉昌,贾志海,雷威,蔡泰民**
(上海理工大学能源与动力工程学院上海 200093)
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摘要:利用聚二甲基硅氧烷(PDMS)制备了微方柱结构疏水表面,分析了微方柱间距和高度
对液滴表面浸润特性的影响。研究发现,随着微方柱间距的增大,粗糙表面表观接触角越大,
但由于间距增大导致粗糙度下降,而平滑 PDMS 表面的表观接触角较小,因此势必存在一
个最佳的微方柱间距,使表观接触角取得最大值。同时对不同高度微方柱结构疏水表面液滴
浸润特性的研究表明:在微方柱间距和边长一定时,微方柱高度对液滴的初始浸润状态影响
较小,但对液滴浸润状态的稳定性影响很大,当微方柱高度较大时,液滴的浸润状态相对较
为稳定,而微方柱高度较低时,液滴会出现接触角突然减小的“坍塌”,由近似 Cassie 状态转
变成 Wenzel 状态;分析认为,应存在一个临界高度,在低于临界高度时,初始液滴在一段
时间后会突然“坍塌”,而高于临界高度时,液滴的浸润状态则相对稳定。
关键词:微结构;表面;间距;高度;浸润特性
中图分类号:
Analysis of wetting characteristics on microstructured
hydrophobic surfaces
HE Jichang, JIA Zhihai, LEI Wei, CAI Taimin
(School of Energy and Power Engineering, University of Shanghai for Science and Technology,
Shanghai, 200093)
Abstract: The pillar-structured hydrophobic surfaces were prepared with the polydimethyl-siloxane
(PDMS) substrate using photolithography techniques. The wettability of the hydrophobic surfaces with
different microstructure spacing and height were studied. Experimental results show that the contact
angle will increase when the microstructure spacing increase. Howerer, the roughness decrease when
the microstructure spacing increases and the contact angle on smooth surfaces is small. So there must
be existing a critical microstructure spacing at which the contact angle on the hydrophobic surface
achieves the biggest value. Furtherfore, th