Transforming soft materials into engines by coupling the Leidenfrost effect to elastic deformations

Condensed Matter lunchtime seminar

Transforming soft materials into engines by coupling the Leidenfrost effect to elastic deformations

Event details

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. In this talk, I will introduce a new phenomenon that occurs with vaporizable soft solids: the elastic Leidenfrost effect. By dropping hydrogel spheres onto hot surfaces we see that, rather than hovering, they energetically bounce several times their diameter for minutes at a time (see attached figure). With high-speed video during a single impact, we uncover high-frequency microscopic gap dynamics at the sphere-substrate interface. These otherwise-hidden agitations constitute work cycles that harvest mechanical energy from the vapour and sustain the bouncing. The findings unleash a widely applicable strategy for injecting mechanical energy into soft materials, with potential relevance to fields ranging from soft robotics and metamaterials to microfluidics and active matter.

About Condensed Matter lunchtime seminars

This is a weekly series of informal talks given primarily by members of the soft condensed matter and statistical mechanics groups, but is also open to members of other groups and external visitors. The aim of the series is to promote discussion and learning of various topics at a level suitable to the broad background of the group. Everyone is welcome to attend..

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