Direct observation of anisotropic growth of water films on minerals driven by defects and surface tension
Direct observation of anisotropic growth of water films on minerals driven by defects and surface tension
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DOI：
10.1126/sciadv.aaz9708
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发表时间：
2020-07
期刊：
影响因子：
13.6
通讯作者：
S. Yalcin;B. Legg;M. Yeşilbaş;N. Malvankar;J. Boily
中科院分区：
文献类型：
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作者：
S. Yalcin;B. Legg;M. Yeşilbaş;N. Malvankar;J. Boily
纳米厚的水膜在单一矿物纳米颗粒上各向异性生长。了解矿物表面水膜的存在对全球地球化学和大气过程，包括元素循环和冰成核至关重要。然而，控制水膜生长的基本机制被误解了。使用红外纳米光谱，调幅原子力显微镜，和分子模拟，我们展示了水膜如何从水蒸气亲水性矿物纳米颗粒生长。我们成像的电影与多达四个水层，各向异性增长超过一个单一的面。生长通常从表面的边缘开始，在那里缺陷优先捕获水蒸气。通过冷凝冷却产生的较厚的膜完全吞没纳米颗粒，并在缺陷上形成较厚的膜。水的高表面张力使膜表面平滑，并产生厚度不均匀的膜。纳米尺度形貌和膜表面能从而控制亲水性矿物纳米颗粒上的水膜的各向异性分布和厚度。
Nanometer-thick water films grow anisotropically over single mineral nanoparticles. Knowledge of the occurrences of water films on minerals is critical for global biogeochemical and atmospheric processes, including element cycling and ice nucleation. The underlying mechanisms controlling water film growth are, however, misunderstood. Using infrared nanospectroscopy, amplitude-modulated atomic force microscopy, and molecular simulations, we show how water films grow from water vapor on hydrophilic mineral nanoparticles. We imaged films with up to four water layers that grow anisotropically over a single face. Growth usually begins from the near edges of a face where defects preferentially capture water vapor. Thicker films produced by condensation cooling completely engulf nanoparticles and form thicker menisci over defects. The high surface tension of water smooths film surfaces and produces films of inhomogeneous thickness. Nanoscale topography and film surface energy thereby control anisotropic distributions and thicknesses of water films on hydrophilic mineral nanoparticles.