n-Octadecanethiol Self-Assembled Monolayer Coating with Microscopic Roughness for Dropwise Condensation of Steam

作     者：Liang CHEN Shiqiang LIANG Runsheng YAN Yanjun CHENG Xiulan HUA Shuling CHEN 

作者机构：Institute of Engineering Thermophysics Chinese Academy of Sciences Beijing 100190 China College of Mechanical and Electronic Control Engineering Beijing Jiaotong University Beijing 100044 China Institute of Light Industry Environment Protect Beijing 100089 China 

出 版 物：《Journal of Thermal Science》 (热科学学报（英文版）)

年 卷 期：2009年第18卷第2期

页      面：160-165页

核心收录：

学科分类：07[理学] 0702[理学-物理学] 

基　　金：supports of the National Natural Seience Foundation of China (Grant No.50706053) the National High Teelmology Research and Development Program of China(863 Prograrn,Grant No.2007AA052259) are gratefully acknowledged 

主　　题：Dropwise condensation Self-assembled monolayers Microscopic roughness Super-hydrophobic surface Heat transfer coefficient 

摘      要：Here we presented a novel technology to achieve a Super-hydrophobic coating with microscopic roughness on copper surface. First, make a layer of verdigris grow on the fresh pure copper surface. Gain it by exposing the copper to air and the mist of acetic acid solution. The green coating is a mixture of basic copper（II） carbonate and copper（II） acetate. Second heat the coating and make it decompose to CuO. Lastly, form an n-octadecanethiol self-assembled monolayers coating on the outermost surface. Contact angle test, scanning electron microscope analysis and electrochemical testing were carded out to characterize the surface, and a heat transfer experiment for dropwise condensation of steam was performed also. Results show that the modified surface bears a few Super-hydrophobic features, the static contact angle is higher than that in literatures, reaching 153.1±1.7°. The microscopic roughness can be seen in SEM images, differing much from H2O2 etched surface and bare copper surface. The condensation of steam on the surface is a typical form of dropwise condensation, in the measured range of temperature difference, under 0.1 MPa, the average convection heat transfer coefficients of the vertical surface are 1.7-2.1 times for those of film condensation. At the same time, the inhibition efficiency of surface is improved to some extent comparing with the same kind of SAMs, which suggests that the lifetime of maintenance dropwise condensation would have the possibility to surpass the existing record.