近日，美国弗吉尼亚理工大学的Jiangtao Cheng及其研究小组与大连理工大学的赵磊等人合作并取得一项新进展。经过不懈努力，他们对微结构表面上固着液滴的低温类莱顿弗罗斯特弹跳进行了研究。相关研究成果已于2024年5月24日在国际知名学术期刊《自然—物理学》上发表。
据悉，莱顿弗罗斯特效应——液滴在高温固体表面悬浮和悬停——通常需要足够高的衬底温度才能激活液体蒸发。
本文报道了微米柱表面上的微滴在相对低温下类莱顿弗罗斯特弹跳的调制。与传统的230°C以上的莱顿弗罗斯特效应相比，鳍状阵列微米柱通过触发液滴底部单个蒸汽泡的惯性控制生长，使水滴在130°C的温度下在几毫秒内悬浮并跳离表面。
研究人员证明了由膨胀的气泡和液滴之间的动量相互作用引起的液滴弹跳，可以通过柱高度调整热边界层厚度来调节。这使得在惯性控制模式和传热限制模式之间调节气泡膨胀成为可能。这两种气泡生长模式分别产生了以恒定速度和恒定能量为特征的不同液滴弹跳行为。这种加热策略允许以可控的方式直接清洗粗糙或结构化表面上的湿润液滴，潜在的应用包括快速去除污垢介质，即使位于表面空腔中。
附：英文原文
Title: Low-temperature Leidenfrost-like jumping of sessile droplets on microstructured surfaces
Author: Huang, Wenge, Zhao, Lei, He, Xukun, Li, Yang, Collier, C. Patrick, Zheng, Zheng, Liu, Jiansheng, Briggs, Dayrl P., Cheng, Jiangtao
Issue&Volume: 2024-05-24
Abstract: The Leidenfrost effect—the levitation and hovering of liquid droplets on hot solid surfaces—generally requires a sufficiently high substrate temperature to activate liquid vaporization. Here we report the modulation of Leidenfrost-like jumping of sessile water microdroplets on micropillared surfaces at a relatively low temperature. Compared to traditional Leidenfrost effect occurring above 230°C, the fin-array-like micropillars enable water microdroplets to levitate and jump off the surface within milliseconds at a temperature of 130°C by triggering the inertia-controlled growth of individual vapour bubbles at the droplet base. We demonstrate that droplet jumping, resulting from momentum interactions between the expanding vapour bubble and the droplet, can be modulated by tailoring of the thermal boundary layer thickness through pillar height. This enables regulation of the bubble expansion between the inertia-controlled mode and the heat-transfer-limited mode. The two bubble-growth modes give rise to distinct droplet jumping behaviours characterized by constant velocity and constant energy regimes, respectively. This heating strategy allows the straightforward purging of wetting liquid droplets on rough or structured surfaces in a controlled manner, with potential applications including the rapid removal of fouling media, even when located in surface cavities.
DOI: 10.1038/s41567-024-02522-z
Source: https://www.nature.com/articles/s41567-024-02522-z