The elastic Leidenfrost effect—An interplay between elasticity and vapor pressure.

When a liquid droplet comes near a surface significantly above its boiling temperature, vaporization can become sufficient to cause it to levitate—this is the Leidenfrost effect [1]. Vaporizable soft solids, e.g., hydrogels, can also exhibit levitation [2], and additionally a sustained bouncing effect [3]. The interplay of elasticity and vapor pressure is essential for these behaviors, but the nature of this interaction is not fully understood. Previous experiments with lateral-view videography [2,3] were insufficient to observe what happens below levitating hydrogels, unable to resolve levitation heights smaller than 20 micrometers, let alone the surface profile of the underbelly. In this talk, I will present results using a three-laser, high-speed interferometric imaging system that allows us to resolve levitation heights down to ~1 micrometer and measure the full height profile.  With our system, we can tease out the system's evolution over timescales ranging from a millisecond to a minute, thus promising to shed light on this unique interplay between elasticity and vapor pressure.

[1] A.-L. Biance, C. Clanet, and D. Quere, Phys. Fluids 15, 1632-1637 (2003).

[2] S. Waitukaitis, K. Harth, and M.v. Hecke, Phys. Rev. Lett. 121, 048001 (2018).

[3] S. Waitukaitis, A. Zuiderwijk, A. Souslov, C. Coulais, and M. v. Hecke, Nat. Phys. 13, 1095–1099 (2017).