Unexpected Suppression of Leidenfrost Phenomenon on Superhydrophobic Surfaces (Under Review)

by M. Shi, R. Das, S. Arunachalam, H. Mishra
Year: 2021

Bibliography

Shi, M., Das, R., Arunachalam, S., Mishra, H. 

Unexpected Suppression of Leidenfrost Phenomenon on Superhydrophobic Surfaces (Under review, Nature Physics)

Abstract

The Leidenfrost phenomenon entails the levitation of a liquid droplet over a superheated surface, cushioned by its vapor layer. For water, superhydrophobic surfaces are believed to suppress the Leidenfrost point ()-the temperature at which this phenomenon occurs. The vapor film obstructs boiling heat transfer in heat exchangers, thereby compromising energy efficiency and safety. Thus, it is desirable to realize superhydrophobicity without suppressing . Here we demonstrate that the  of water on microtextured superhydrophobic surfaces comprising doubly reentrant pillars (DRPs) can exceed those on hydrophilic and even superhydrophilic surfaces. We disentangle the contributions of microtexture, heat transfer, and surface chemistry on  and reveal how superhydrophobicity can be realized without suppressing . For instance, silica surfaces with DRPs facilitate ~300% greater heat transfer to water droplets at 200C in comparison with silica surfaces coated with perfluorinated-nanoparticles. Thus, superhydrophobic surfaces could be harnessed for energy-efficient thermal machinery.