Nonspecular Reflection of Droplets

Pingan Zhu, Chengmin Chen, Krishnaswamy Nandakumar, Liqiu Wang*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

The bouncing of droplets on super-repellent surfaces normally resembles specular reflection that obeys the law of reflection. Here, the nonspecular reflection of droplet impingement onto solid surfaces with a dimple for energy-efficient, omnidirectional droplet transport is reported. With the dimple of the radius being comparable to that of the droplet, all the symmetries in the law of reflection can be broken down so that the droplet is endowed with a translational velocity finely tunable in both its direction and magnitude simply by varying the radii of the droplet and the dimple, the impinging position, and droplet Weber number. Tailoring the initial and translational velocity of impinging droplets would steer their reflected trajectories at will, thus enabling versatile droplet manipulation including trapping, shedding, antigravity transport, targeted positioning, and on-demand coalescence of droplets.

Original languageEnglish
JournalSmall
DOIs
StateAccepted/In press - 2020
Externally publishedYes

Keywords

  • droplet impact
  • liquid repellency
  • nonspecular reflection of droplets
  • omnidirectional droplet transport
  • symmetry breaking

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