Uhlig Manuel R, Garcia Ricardo
Instituto de Ciencia de Materiales de Madrid, CSIC, c/Sor Juana Inés de la Cruz 3, 28049 Madrid, Spain.
Nano Lett. 2021 Jul 14;21(13):5593-5598. doi: 10.1021/acs.nanolett.1c01092. Epub 2021 May 13.
Capillary condensation of water from vapor is an everyday phenomenon which has a wide range of scientific and technological implications. Many aspects of capillary condensation are not well understood such as the structure of interfacial water, the existence of distinct properties of confined water, or the validity of the Kelvin equation at nanoscale. We note the absence of high-spatial resolution images inside a meniscus. Here, we develop an AFM-based method to provide atomic-scale resolution maps of the solid-water interface of a nanomeniscus (80-250 nm). The separation between the first two hydration layers on graphite is 0.30 nm, while on mica it is 0.28 nm. Those values are very close to the ones expected for the same surfaces immersed in bulk water. Thus, the hydration layer structure on a crystalline surface is independent of the water volume.
水蒸气在毛细管中凝结是一种常见现象，具有广泛的科学和技术意义。毛细管凝结的许多方面尚未得到很好的理解，例如界面水的结构、受限水独特性质的存在，或者开尔文方程在纳米尺度下的有效性。我们注意到弯月面内部缺乏高空间分辨率图像。在这里，我们开发了一种基于原子力显微镜的方法，以提供纳米弯月面（80 - 250纳米）固 - 水界面的原子尺度分辨率图。石墨上前两个水化层之间的间距为0.30纳米，而云母上为0.28纳米。这些值与浸入大量水中的相同表面预期的值非常接近。因此，晶体表面的水化层结构与水量无关。
