马朗戈尼效应
去湿
肺表面活性物质
表面张力
毛细管作用
化学工程
材料科学
化学
薄膜
化学物理
复合材料
纳米技术
热力学
物理
工程类
作者
Zhizhao Che,Omar Matar
出处
期刊:Langmuir
[American Chemical Society]
日期:2017-08-17
卷期号:33 (43): 12140-12148
被引量:27
标识
DOI:10.1021/acs.langmuir.7b01901
摘要
The impact of droplets on liquid films is ubiquitous in natural and industrial processes, and surfactants can significantly alter the impact process by changing the local surface tension. Here we study the impact of droplets on liquid films in the presence of surfactant using high-speed photography, and reveal the flow pattern by dye-tracing. The effects of the droplet size and speed, and the initial film thickness on the impact process are elucidated. The results show that the flow is significantly affected by adding surfactant to the droplet, the liquid film, or to both phases. In particular, the film dye patterns form concentric circles and flower-shaped structures at low and high droplet Weber numbers, respectively. We also show how surfactant-induced Marangoni stresses modify these flow patterns, and alter the characteristics of the phenomena associated with the impact process, such as the propagation of capillary waves, the evolution of the crown, and the formation of secondary droplets. During the impact of surfactant droplets on thin water films, the Marangoni stresses can be sufficiently strong so as to drive film dewetting.
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