Mechanism of supercooled droplet freezing on surfaces
Mechanism of supercooled droplet freezing on surfaces
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DOI：
10.1038/ncomms1630
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发表时间：
2012-01-01
影响因子：
16.6
通讯作者：
Poulikakos, Dimos
中科院分区：
文献类型：
--
作者：
Jung, Stefan;Tiwari, Manish K.;Poulikakos, Dimos
了解过冷水在表面上的冰形成是一个具有根本重要性和普遍实用性的问题。超疏水表面有可能具有显著的“疏冰性”和低冰粘附性。在这里，我们表明，它们的疏冰性可以通过简单的环境条件的变化而变得无效。通过实验、成核理论和传热物理学，我们确定湿度和/或周围气体的流动可以从根本上改变冰的结晶机制，从而极大地影响表面的疏冰性。过冷液体的蒸发冷却可以通过在无液滴表面处的均质成核而产生冰结晶，这与预期的在基底处的非均质成核相反。还研究了液滴滚降和快速结晶之间的相关相互作用。总的来说，我们带来了一个新的视角结冰和icephobicity，除了表面条件和疏水性的公认效果，揭示了环境条件的强烈影响。
Understanding ice formation from supercooled water on surfaces is a problem of fundamental importance and general utility. Superhydrophobic surfaces promise to have remarkable 'icephobicity' and low ice adhesion. Here we show that their icephobicity can be rendered ineffective by simple changes in environmental conditions. Through experiments, nucleation theory and heat transfer physics, we establish that humidity and/or the flow of a surrounding gas can fundamentally switch the ice crystallization mechanism, drastically affecting surface icephobicity. Evaporative cooling of the supercooled liquid can engender ice crystallization by homogeneous nucleation at the droplet-free surface as opposed to the expected heterogeneous nucleation at the substrate. The related interplay between droplet roll-off and rapid crystallization is also studied. Overall, we bring a novel perspective to icing and icephobicity, unveiling the strong influence of environmental conditions in addition to the accepted effects of the surface conditions and hydrophobicity.