Abstract <p>Introducing macroscale grooves on superhydrophobic surfaces is known to shorten droplet contact time substantially. However, the dependence of this effect on surface inclination remains largely unexplored. Here, we investigate droplet impact dynamics on a grooved superhydrophobic surface by systematically varying both the surface inclination angle and impact velocity through high-speed imaging. A pronounced reduction in contact time due to petal bouncing&#xa0;persisted up to the surface inclination angle of approximately 20°, but diminished rapidly at larger angles, and was no longer observed at inclination angles above 50°. This behavior is governed by whether the surface energy stored during impact can lift the entire droplet expanded in the downstream direction. When the droplet tangential length exceeded a critical threshold, only the droplet tail lifted off, producing a distinct tail rebound mode. The onset Weber number for the abrupt decrease in contact time shows excellent agreement with predictions from a semi-empirical model.</p> Graphical abstract <p></p>

错误:搜索内容不能为空,请输入英文关键词
错误:关键词超出字数限制,请精简
高级检索

Effect of macroscopic grooves on contact time reduction of water droplets on an inclined superhydrophobic surface

  • Jeongwon Seo,
  • Yejun Yun,
  • Changhun Park,
  • Jeong-Hyun Kim

摘要

Abstract

Introducing macroscale grooves on superhydrophobic surfaces is known to shorten droplet contact time substantially. However, the dependence of this effect on surface inclination remains largely unexplored. Here, we investigate droplet impact dynamics on a grooved superhydrophobic surface by systematically varying both the surface inclination angle and impact velocity through high-speed imaging. A pronounced reduction in contact time due to petal bouncing persisted up to the surface inclination angle of approximately 20°, but diminished rapidly at larger angles, and was no longer observed at inclination angles above 50°. This behavior is governed by whether the surface energy stored during impact can lift the entire droplet expanded in the downstream direction. When the droplet tangential length exceeded a critical threshold, only the droplet tail lifted off, producing a distinct tail rebound mode. The onset Weber number for the abrupt decrease in contact time shows excellent agreement with predictions from a semi-empirical model.

Graphical abstract