Coupling the Leidenfrost Effect and Elastic Deformations to Power Sustained Bouncing
Abstract
The Leidenfrost effect occurs when an object near a hot surface vaporizes rapidly enough to lift itself up and hover. Although well-understood for liquids and stiff sublimable solids, nothing is known about the effect with materials whose stiffness lies between these extremes. Here we introduce a new phenomenon that occurs with vaporizable soft solids: the elastic Leidenfrost effect. By dropping hydrogel spheres onto hot surfaces we find that, rather than hovering, they energetically bounce several times their diameter for minutes at a time. With high-speed video during a single impact, we uncover high-frequency microscopic gap dynamics at the sphere-substrate interface. We show how these otherwise-hidden agitations constitute work cycles that harvest mechanical energy from the vapour and sustain the bouncing. Our findings unleash a powerful and widely applicable strategy for injecting mechanical energy into soft materials, with relevance to fields ranging from soft robotics and metamaterials to microfluidics and active matter.
Cite
@article{arxiv.1705.03530,
title = {Coupling the Leidenfrost Effect and Elastic Deformations to Power Sustained Bouncing},
author = {Scott R. Waitukaitis and Antal Zuiderwijk and Anton Souslov and Corentin Coulais and Martin van Hecke},
journal= {arXiv preprint arXiv:1705.03530},
year = {2017}
}