Analysis of meniscus beneath metastable droplets and wetting transition on micro/nano textured surfaces

作     者：Yaniie Li Xiangqin Li Tianqing Liu Weiguo Song 李艳杰;李香琴;刘天庆;宋伟国

作者机构：School of Chemical EngineeringDaliat7 University of TechnologyDalian 116024China School of PharmacyWeifang Medical UniversityWeifang 261053China 

出 版 物：《Chinese Physics B》 (中国物理B（英文版）)

年 卷 期：2018年第27卷第8期

页      面：439-449页

核心收录：

学科分类：07[理学] 0702[理学-物理学] 

基　　金：Project supported by the National Natural Science Foundation of China(Grant No.21676041) 

主　　题：interface free energy droplet wetting transition energy barrier 

摘      要：Tile expressions of interface flee energy （IFE） of composite droplets with meniscal liquid-air interlhce in metastable state on nlicro/nano textured snrfaces were formulated. Then tile parameters to describe the meniscus were determined based on the principle of minimtun 1FE. Furthermore, the IFE barriers and the necessary and sufficient conditions of drop wetting transition fl＇om Cassie to Wenzel were analyzed and the corresponding criteria were lk^rmulated. The results show that the liquid-air interface below a composite droplet is fiat when the post pitches are relatively small, but in a shape of curved meniscus when the piteches are comparatively large and the curvature depends on structural parameters. The angle between meniscus and pillar wall is just equal to the supplementary angle of intrinsic contact angle of post material. The calculations also illustrate that Cassie droplets will transform to Wenzel state when post pitch is large enough or when drop volume is sufficiently small. The opposite transition from Wenzel to Cassie state, however, is unable to take place spontaneously because the energy barrier is always positive. Finally, the calculation results of this model are well consistent with tile experimental obserwttions in literatures for the wetting transition of droplets from Cassie to Wenzel state.