Molecular Simulation of the Phase Behavior of Water Confined in Silica Nanopores
Molecular Simulation of the Phase Behavior of Water Confined in Silica Nanopores
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DOI：
10.1021/jp067380g
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发表时间：
2007-05
影响因子：
3.7
通讯作者：
K. Shirono;H. Daiguji
中科院分区：
文献类型：
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作者：
K. Shirono;H. Daiguji
在300 K的温度下，对直径1.04、1.96和2.88 nm的二氧化硅孔隙（分别为孔隙S、M和L）中的水分子进行了分子动力学模拟和大正则蒙特卡罗模拟，揭示了每个孔隙中水分子可能的相态，并阐明了孔径和水化水平对纳米孔中水分子结构和动力学性质的影响。纳米孔中存在三种相。在第一阶段，出现在孔隙S、M和L中，孔隙表面的气相水吸附低于单层覆盖。第二相出现在孔隙S和L中，孔隙表面有一层冷凝水单层。在第三阶段，出现在孔隙M和L中，孔隙完全充满水。在低水合作用下，当水分子数量远小于硅醇时，水分子主要通过氢键与硅醇基相互作用。随着水分子数的增加，水分子摩尔数比增大。
Molecular dynamics simulations and grand canonical Monte Carlo simulations of water molecules in 1.04, 1.96, and 2.88 nm diameter silica pores (pores S, M, and L, respectively) were conducted at 300 K to reveal possible phase states of water in each pore and clarify the effect of pore diameter and hydration level on the structural and dynamical properties of water molecules confined in nanopores. Three types of phases appear in nanopores. In the first phase, which appears in pores S, M, and L, gas-phase water adsorption at the pore surface is below monolayer coverage. In the second phase, which appears in pores S and L, there is a condensed water monolayer at the pore surface. In the third phase, which appears in pores M and L, the pore is completely filled with water. Water molecules interact with silanol groups mainly via hydrogen bonds at low hydration when the number of water molecules is much smaller than that of silanol groups. With increasing number of water molecules, the number ratio of water mol...