Key Laboratory of Green Printing, CAS Research/Education Center for Excellence in Molecular Sciences, Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, 100190, Beijing, P. R. China.
University of Chinese Academy of Sciences, 100049, Beijing, P. R. China.
Nat Commun. 2023 May 8;14(1):2646. doi: 10.1038/s41467-023-38366-z.
For a drop on a very hot solid surface, a vapor film will form beneath the drop, which has been discovered by Leidenfrost in 1756. The vapor escaping from the Leidenfrost film causes uncontrollable flows, and actuates the drop to move around. Recently, although numerous strategies have been used to regulate the Leidenfrost vapor, the understanding of surface chemistry for modulating the phase-change vapor dynamics remains incomplete. Here, we report how to rectify vapor by "cutting" the Leidenfrost film using chemically heterogeneous surfaces. We demonstrate that the segmented film cut by a Z-shaped pattern can spin a drop, since the superhydrophilic region directly contacts the drop and vaporizes the water, while a vapor film is formed on the superhydrophobic surrounding to jet vapor and reduce heat transfer. Furthermore, we reveal the general principle between the pattern symmetry design and the drop dynamics. This finding provides new insights into the Leidenfrost dynamics modulation, and opens a promising avenue for vapor-driven miniature devices.
对于非常热的固体表面上的液滴，会在液滴下方形成蒸汽膜，这是莱顿弗罗斯特在 1756 年发现的。莱顿弗罗斯特膜逸出的蒸汽会引起不可控的流动，并使液滴四处移动。最近，尽管已经使用了许多策略来调节莱顿弗罗斯特蒸汽，但对于控制相变蒸汽动力学的表面化学的理解仍然不完整。在这里，我们报告了如何通过使用化学异质表面“切割”莱顿弗罗斯特膜来纠正蒸汽。我们证明，通过 Z 形图案切割的分段膜可以使液滴旋转，因为超亲水区域直接与液滴接触并使水蒸发，而在超疏水周围形成蒸汽膜以喷射蒸汽并减少热传递。此外，我们揭示了图案对称设计和液滴动力学之间的一般原理。这一发现为莱顿弗罗斯特动力学调制提供了新的见解，并为蒸汽驱动的微型设备开辟了广阔的前景。
