The Many Faces of Heterogeneous Ice Nucleation: Interplay Between Surface Morphology and Hydrophobicity
The Many Faces of Heterogeneous Ice Nucleation: Interplay Between Surface Morphology and Hydrophobicity
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DOI：
10.1021/jacs.5b08748
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发表时间：
2015-10-28
影响因子：
15
通讯作者：
Michaelides, Angelos
中科院分区：
文献类型：
--
作者：
Fitzner, Martin;Sosso, Gabriele C.;Michaelides, Angelos
是什么使一种材料成为良好的冰核剂？尽管非均质冰成核对从云科学到微生物学的各个领域都很重要，但我们对这一无处不在的过程的理解存在重大差距，仍然阻碍我们回答这个问题。在这项工作中，我们研究了普通晶体基质促进冰核形成的能力作为疏水性和表面形态的函数。通过改变水表面相互作用和表面晶格参数，对粗粒水在模型面心立方晶体不同表面上的成核速率进行了分子动力学模拟。结果表明，表面与冰的晶格失配，通常被认为是良好的冰核剂的最重要要求，是最理想的，但不是必需的。另一方面，表面形态和疏水性之间的平衡可以显著改变冰核的成核速度，还可以导致在同一基质上形成多达三个不同的冰面。我们已经准确地指出了晶体表面可以促进非均质冰成核的三种情况：(I)作为面内模板的水覆盖层的形成；(Ii)以冰的方式弯曲的接触层的出现；以及(Iii)在具有非常高的相互作用强度的致密表面上的成核。我们希望这一广泛的系统研究将促进未来的实验。旨在测试本文提出的物理化学理解的工作。
What makes a material a good ice nucleating agent? Despite the importance of heterogeneous ice nucleation to a variety of fields, from cloud science to microbiology, major gaps in our understanding of this ubiquitous process still prevent us from answering this question. In this work, we have examined the ability of generic crystalline substrates to promote ice nucleation as a function of the hydrophobicity and the morphology of the surface. Nucleation rates have been obtained by brute-force molecular dynamics simulations of coarse-grained water on top of different surfaces of a model fcc crystal, varying the water surface interaction and the surface lattice parameter. It turns out that the lattice mismatch of the surface with respect to ice, customarily regarded as the most important requirement for a good ice nucleating agent, is at most desirable but not a requirement. On the other hand, the balance between the morphology of the surface and its hydrophobicity can significantly alter the ice nucleation rate and can also lead to the formation of up to three different faces of ice on the same substrate. We have pinpointed three circumstances where heterogeneous ice nucleation can be promoted by the crystalline surface: (i) the formation of a water overlayer that acts as an in-plane template; (ii) the emergence of a contact layer buckled in an ice-like manner; and (iii) nucleation on compact surfaces with very high interaction strength. We hope that this extensive systematic study will foster future experimental. work aimed at testing the physiochemical understanding presented herein.