Water in Inhomogeneous Nanoconfinement: Coexistence of Multi layered Liquid and Transition to Ice Nanoribbons
Water in Inhomogeneous Nanoconfinement: Coexistence of Multi layered Liquid and Transition to Ice Nanoribbons
复制标题
不均匀纳米限制中的水：多层液体的共存和向冰纳米带的过渡。
DOI：
10.1021/acsnano.5b04947
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发表时间：
2015
期刊：
影响因子：
17.1
通讯作者：
Guo Wanlin
中科院分区：
文献类型：
--
作者：
Qiu Hu;Zeng Xiao Cheng;Guo Wanlin
利用分子动力学模拟研究了水在非均匀纳米约束下的相行为和相转变。该纳米约束由一个平面底板和一个凸顶板构成。在300 K时，承压水可以看作是单层、双层和三层液体域的共存，以适应不均匀的约束。随着液体密度的增加，层数不均匀的承压水分别转化为层数不变、氧原子面内对称的二维冰晶。单层水首先转变为皱褶冰纳米带，双层水随后转变为菱形冰纳米带，三层水随后转变为三层冰纳米带。在低液体密度条件下，通过逐渐降低温度也可以实现非均匀约束条件下的连续局部液固转变。这些非均匀纳米约束条件下水的相行为的发现不仅扩展了约束水的相图，而且对现实的纳米流体系统和微孔材料具有指导意义。
Phase behavior and the associated phase transition of water within inhomogeneous nanoconfinement are investigated using molecular dynamics simulations. The nanoconfinement is constructed by a flat bottom plate and a convex top plate. At 300 K, the confined water can be viewed as a coexistence of monolayer, bilayer, and trilayer liquid domains to accommodate the inhomogeneous confinement. With increasing liquid density, the confined water with uneven layers transforms separately into two-dimensional ice crystals with unchanged layer number and rhombic in-plane symmetry for oxygen atoms. The monolayer water undergoes the transition first into a puckered ice nanoribbon, and the bilayer water transforms into a rhombic ice nanoribbon next, followed by the transition of trilayer water into a trilayer ice nanoribbon. The sequential localized liquid-to-solid transition within the inhomogeneous confinement can also be achieved by gradually decreasing the temperature at low liquid densities. These findings of phase behaviors of water under the inhomogeneous nanoconfinement not only extend the phase diagram of confined water but also have implications for realistic nanofluidic systems and microporous materials.