中国物理B ›› 2021, Vol. 30 ›› Issue (4): 46501-.doi: 10.1088/1674-1056/abeedb

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  • 收稿日期:2020-11-16 修回日期:2021-01-21 接受日期:2021-03-16 出版日期:2021-03-16 发布日期:2021-03-24

A comparative study of the self-propelled jumping capabilities of coalesced droplets on RTV surfaces and superhydrophobic surfaces

Sheng-Wu Wang(王晟伍), Lu Peng(彭璐), Jun-Wu Chen(陈俊武), and Lee Li(李黎)   

  1. 1 School of Electrical and Electronic Engineering, Huazhong University of Science & Technology, Wuhan 430074, China
  • Received:2020-11-16 Revised:2021-01-21 Accepted:2021-03-16 Online:2021-03-16 Published:2021-03-24
  • Contact: Corresponding author. E-mail: leeli@hust.edu.cn

Abstract: Understanding the mechanism of coalescence-induced self-propelled jumping behavior provides distinct insights in designing and optimizing functional coatings with self-cleaning and anti-icing properties. However, to date self-propelled jumping phenomenon has only been observed and studied on superhydrophobic surfaces, other than those hydrophobic surfaces with weaker but fairish water-repellency, for instance, vulcanized silicon rubber (RTV) coatings. In this work, from the perspective of thermodynamic-based energy balance aspect, the reason that self-propelled jumping phenomenon does not happen on RTV coatings is studied. The apparent contact angles of droplets on RTV coatings can be less than the theoretical critical values therefore cannot promise energy surplus for the coalesced droplets onside. Besides, on RTV and superhydrophobic surfaces, the droplet-size dependent variation characteristics of the energy leftover from the coalescence process are opposite. For the droplets coalescing on RTV coatings, the magnitudes of energy dissipations are more sensitive to the increase in droplet size, compared to that of released surface energy. While for superhydrophobic coatings, the energy generated during the coalescence process can be more sensitive than the dissipations to the change in droplet size.

Key words: self-propelled jumping, vulcanized silicon rubber (RTV), superhydrophobicity, self-cleaning

中图分类号:  (Surface energy)

  • 65.40.gp
45.20.dh (Energy conservation) 68.03.Cd (Surface tension and related phenomena) 68.08.-p (Liquid-solid interfaces)