From Bouncing to Floating: The Leidenfrost Effect with Hydrogel Spheres.
From Bouncing to Floating: The Leidenfrost Effect with Hydrogel Spheres.
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DOI：
10.1103/physrevlett.121.048001
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发表时间：
2018-07
影响因子：
8.6
通讯作者：
S. Waitukaitis;K. Harth;M. van Hecke
中科院分区：
文献类型：
--
作者：
S. Waitukaitis;K. Harth;M. van Hecke
当靠近炎热表面的液体或坚硬的可升华固体在其下方产生足够的水蒸气，使其上升并漂浮时，就会产生莱登弗罗斯特效应。相比之下，可蒸发的软固体，例如水凝胶，已被证明具有持久的反弹--弹性莱登弗罗斯特效应。通过小心地将水凝胶球降低到高温表面，我们发现它们也能够漂浮。从反弹到浮动的转变由接近速度和温度控制，类似于“动态莱登弗罗斯特效应”。对于浮动区域，我们测量了能隙几何形状的指数标度，我们用一个将蒸发速率耦合到球形形状的模型来解释这一点。我们的结果表明，水凝胶是一种很有前途的通过形状控制漂浮的莱登弗罗斯特物体的途径。
The Leidenfrost effect occurs when a liquid or stiff sublimable solid near a hot surface creates enough vapor beneath it to lift itself up and float. In contrast, vaporizable soft solids, e.g., hydrogels, have been shown to exhibit persistent bouncing-the elastic Leidenfrost effect. By carefully lowering hydrogel spheres towards a hot surface, we discover that they are also capable of floating. The bounce-to-float transition is controlled by the approach velocity and temperature, analogously to the "dynamic Leidenfrost effect." For the floating regime, we measure power-law scalings for the gap geometry, which we explain with a model that couples the vaporization rate to the spherical shape. Our results reveal that hydrogels are a promising pathway for controlling floating Leidenfrost objects through shape.