中国物理B ›› 2018, Vol. 27 ›› Issue (8): 86801-086801.doi: 10.1088/1674-1056/27/8/086801
• CONDENSED MATTER: STRUCTURAL, MECHANICAL, AND THERMAL PROPERTIES • 上一篇 下一篇
Analysis of meniscus beneath metastable droplets and wetting transition on micro/nano textured surfaces
Yanjie Li(李艳杰), Xiangqin Li(李香琴), Tianqing Liu(刘天庆), Weiguo Song(宋伟国)
- 1 School of Chemical Engineering, Dalian University of Technology, Dalian 116024, China;
2 School of Pharmacy, Weifang Medical University, Weifang 261053, China
Analysis of meniscus beneath metastable droplets and wetting transition on micro/nano textured surfaces
Yanjie Li(李艳杰)2, Xiangqin Li(李香琴)1, Tianqing Liu(刘天庆)1, Weiguo Song(宋伟国)2
- 1 School of Chemical Engineering, Dalian University of Technology, Dalian 116024, China;
2 School of Pharmacy, Weifang Medical University, Weifang 261053, China
摘要： The expressions of interface free energy (IFE) of composite droplets with meniscal liquid-air interface in metastable state on micro/nano textured surfaces were formulated. Then the parameters to describe the meniscus were determined based on the principle of minimum IFE. Furthermore, the IFE barriers and the necessary and sufficient conditions of drop wetting transition from Cassie to Wenzel were analyzed and the corresponding criteria were formulated. The results show that the liquid-air interface below a composite droplet is flat 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 the experimental observations in literatures for the wetting transition of droplets from Cassie to Wenzel state.
中图分类号: (Liquid-solid interfaces)
- 68.08.-p