Water confined in nanotubes and between graphene sheets: A first principle study
Water confined in nanotubes and between graphene sheets: A first principle study
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DOI：
10.1021/ja074418
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发表时间：
2008-02-13
影响因子：
15
通讯作者：
Galli, Giulia
中科院分区：
文献类型：
--
作者：
Cicero, Giancarlo;Grossman, Jeffrey C.;Galli, Giulia
近年来，纳米尺度受限的水一直是众多实验和理论研究的焦点，然而对于受限条件下的扩散以及氢键（HB）的性质等基本特性尚未达成共识。揭示这些特性对于理解纳米尺度的流体流动和传输以及阐明生物分子的溶剂化作用非常重要。在此，我们报道了一项基于第一性原理的计算研究，重点关注原型非极性基底（即间距为1 - 2.5 nm的单壁碳纳米管和石墨烯片）之间受限的水。我们的分子动力学模拟结果表明存在一个薄的界面液体层（约5埃），其微观结构和厚度与限制层之间的距离无关。即使在强受限的情况下，氢键网络的特性与界面区域外的体相特性也非常相似。我们的研究结果表明，限制介质的存在所引起的扰动在液态水中是极其局部的，并且我们提出，许多归因于受限条件下新相的效应是由在与限制介质的界面处发生的微妙电子结构重排所决定的。
Water confined at the nanoscale has been the focus of numerous experimental and theoretical investigations in recent years, yet there is no consensus on such basic properties as diffusion and the nature of hydrogen bonding (HB) under confinement. Unraveling these properties is important to understand fluid flow and transport at the nanoscale, and to shed light on the solvation of biomolecules. Here we report on a first principle, computational study focusing on water confined between prototypical nonpolar substrates, i.e., single-wall carbon nanotubes and graphene sheets, 1-2.5 nm apart. The results of our molecular dynamics simulations show the presence of a thin, interfacial liquid layer (similar to 5 angstrom) whose microscopic structure and, thickness are independent of the distance between confining layers. The properties of the HB network are very similar to those of the bulk outside the interfacial region, even in the case of strong confinement. Our findings indicate that the perturbation induced by the presence of confining media is extremely local in liquid water, and we propose that many of the effects attributed to novel phases under confinement are determined by subtle electronic structure rearrangements occurring at the interface with the confining medium.