Ricocheting Droplets Moving on Super-Repellent Surfaces

Shuaijun Pan, Rui Guo, Joseph J. Richardson, Joseph D. Berry, Quinn A. Besford, Mattias Björnmalm, Gyeongwon Yun, Ruoxi Wu, Zhixing Lin, Qi Zhi Zhong, Jiajing Zhou, Qiang Sun, Jianhua Li, Yanbing Lu, Zhichao Dong, Margaret Katherine Banks, Weijian Xu, Jianhui Jiang, Lei Jiang, Frank Caruso

Research output: Contribution to journalArticlepeer-review

21 Scopus citations


Droplet bouncing on repellent solid surfaces (e.g., the lotus leaf effect) is a common phenomenon that has aroused interest in various fields. However, the scenario of a droplet bouncing off another droplet (either identical or distinct chemical composition) while moving on a solid material (i.e., ricocheting droplets, droplet billiards) is scarcely investigated, despite it having fundamental implications in applications including self-cleaning, fluid transport, and heat and mass transfer. Here, the dynamics of bouncing collisions between liquid droplets are investigated using a friction-free platform that ensures ultrahigh locomotion for a wide range of probing liquids. A general prediction on bouncing droplet–droplet contact time is elucidated and bouncing droplet–droplet collision is demonstrated to be an extreme case of droplet bouncing on surfaces. Moreover, the maximum deformation and contact time are highly dependent on the position where the collision occurs (i.e., head-on or off-center collisions), which can now be predicted using parameters (i.e., effective velocity, effective diameter) through the concept of an effective interaction region. The results have potential applications in fields ranging from microfluidics to repellent coatings.

Original languageEnglish (US)
Article number1901846
JournalAdvanced Science
Issue number21
StatePublished - Nov 1 2019


  • contact time
  • droplet bouncing
  • interfacial phenomena
  • repellent coatings
  • surface science

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Chemical Engineering(all)
  • Materials Science(all)
  • Biochemistry, Genetics and Molecular Biology (miscellaneous)
  • Engineering(all)
  • Physics and Astronomy(all)


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