CONCAVE BIOLOGICAL SURFACES FOR STRONG WET ADHESION

作     者：Yewang Su Baohua Ji Yonggang Huang Kehchih Hwang 

作者机构：Department of Engineering Mechanics Tsinghua University Beijing 100084 China Department of Applied Mechanics Beijing Institute of Technology Beijing 100081 China Department of Civil and Environmental Engineering Northwestern University Evanston IL 60208 USA 

出 版 物：《Acta Mechanica Solida Sinica》 (固体力学学报（英文版）)

年 卷 期：2009年第22卷第6期

页      面：593-604页

核心收录：

学科分类：081702[工学-化学工艺] 07[理学] 08[工学] 0817[工学-化学工程与技术] 0701[理学-数学] 070101[理学-基础数学] 

基　　金：supported by the National Natural Science Foundation of China through Grant Nos 10628205,10732050 and10872115 National Basic Research Program of China through Grant No 2007CB936803,and SRF-SEM for ROCS 

主　　题：biological surface wet adhesion contact shape concave surface robustness ad- hesion force 

摘      要：Plant leaves, insects and geckos are masters of adhesion or anti-adhesion by smartly designed refined surface structures with micro- and nano- ＇technologies＇. Understanding the basic principles in the design of the unique surface structures is of great importance in the manufacture or synthesis of micro- and nano- devices in MEMS or NEMS. This study is right inspired by this effort, focusing on the mechanics of wet adhesion between fibers having concave tips and a flat substrate via capillary forces. We show that the concave surface can effectively enhance the wet adhesion by reducing the effective contact angle of the fiber, firmly pinning the liquid bridge at its circumferential edge. A critical contact angle is identified below which the adhesion strength can achieve its maximum, being insensitive to the contact angle between the fiber and liquid. The analytical expression for the critical angle is derived. Then a tentative design for the profile of concave surfaces is proposed, considering the effects of chamfering size, deformation and buckling, etc. The effect of liquid volume on the wet adhesion of multiple-fiber system is also discussed.