Energy Loss for Droplets Bouncing Off Superhydrophobic Surfaces

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A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
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Date
2023-02-28
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Language
en
Pages
6
3162–3167
Series
Langmuir, Volume 39, issue 8
Abstract
A water droplet can bounce off superhydrophobic surfaces multiple times before coming to a stop. The energy loss for such droplet rebounds can be quantified by the ratio of the rebound speed UR and the initial impact speed UI; i.e., its restitution coefficient e = UR/UI. Despite much work in this area, a mechanistic explanation for the energy loss for rebounding droplets is still lacking. Here, we measured e for submillimeter-and millimeter-sized droplets impacting two different superhydrophobic surfaces over a wide range of UI (4- 700 cm s-1). We proposed simple scaling laws to explain the observed nonmonotonic dependence of e on UI. In the limit of low UI, energy loss is dominated by contact-line pinning and e is sensitive to the surface wetting properties, in particular to contact angle hysteresis Delta cos 0 of the surface. In contrast, e is dominated by inertial-capillary effects and does not depend on Delta cos 0 in the limit of high UI.
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The authors thank Wang and co-workers for sharing their data with us. Publisher Copyright: © 2023 American Chemical Society.
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Citation
Thenarianto , C , Koh , X Q , Lin , M , Jokinen , V & Daniel , D 2023 , ' Energy Loss for Droplets Bouncing Off Superhydrophobic Surfaces ' , Langmuir , vol. 39 , no. 8 , pp. 3162–3167 . https://doi.org/10.1021/acs.langmuir.2c03449