Drops can bounce from perfectly hydrophilic surfaces

J. M. Kolinski*, L. Mahadevan, S. M. Rubinstein

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

104 Scopus citations

Abstract

Drops are well known to rebound from superhydrophobic surfaces and from liquid surfaces. Here, we show that drops can also rebound from a superhydrophilic solid surface such as an atomically smooth mica sheet. However, the coefficient of restitution CR associated with this process is significantly lower than that associated with rebound from superhydrophobic surfaces. A direct imaging method allows us to characterize the dynamics of the deformation of the drop in entering the vicinity of the surface. We find that drop bouncing occurs without the drop ever touching the solid and there is a nanometer-scale film of air that separates the liquid and solid, suggesting that shear in the air film is the dominant source of dissipation during rebound. Furthermore, we see that any discrete nanometer-height defects on an otherwise hydrophilic surface, such as treated glass, completely inhibits the bouncing of the drop, causing the liquid to wet the surface. Our study adds a new facet to the dynamics of droplet impact by emphasizing that the thin film of air can play a role not just in the context of splashing but also bouncing, while highlighting the role of rare surface defects in inhibiting this response.

Original languageAmerican English
Article number24001
JournalLettere Al Nuovo Cimento
Volume108
Issue number2
DOIs
StatePublished - 1 Oct 2014
Externally publishedYes

Bibliographical note

Publisher Copyright:
Copyright © EPLA, 2014.

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