2022/12/14 by Wenge Huang, Huang, Wenge, Zhao, Lei +7
Engineering · Materials Science · Physics and Astronomy · #FOS: Physical sciences #Fluid Dynamics (physics.flu-dyn) #Fluid Dynamics and Heat Transfer #Micro and Nano Robotics #Surface Modification and Superhydrophobicity
paper · pdf · doi:10.48550/arxiv.2212.07334
openalex publication_date 2022/12/14 · openalex created_date 2022/12/27 · openalex updated_date 2026/07/28
The Leidenfrost effect, namely the levitation and hovering of liquid drops on hot solid surfaces, generally requires a sufficiently high substrate temperature to activate the intense liquid vaporization. Here we report the agile modulations of Leidenfrost-like prompt jumping of sessile water microdroplets on micropillared surfaces at a remarkably mitigated temperature. Compared to traditional Leidenfrost effect occurring above 230 °C, the fin-array-like micropillars enables Wenzel-state water microdroplets to levitate and jump off within 1.33 ms at an unprecedently low temperature of 130 °C by triggering the inertia-controlled growth of individual vapor bubbles at the droplet base. We demonstrate that droplet jumping, resulting from the momentum interactions between the expanding vapor bubble and the droplet, can be deftly modulated by simply tailoring the thermal boundary layer thickness via pillar heights, which acts to regulate the bubble expansion between the inertia-controlled mode and the heat-transfer-limited mode. Intriguingly, the two bubble growth modes give rise to distinct droplet jumping behaviors characterized by constant velocity and constant energy schemes, respectively. This strategy allows the facile purging of wetting liquid drops on rough or structured surfaces in a controlled manner, inspiring promising applications in rapid removal of fouling even settled in surface cavities.