受限在单壁碳纳米管中水分子的扩散

将碳纳米管引入到与生命息息相关的离子通道膜的研究逐渐成为热点,其中的关键是要了解受限在膜孔道(碳纳米管)中的水分子行为.采用分子动力学模拟的方法研究分析了水分子在(6,6)、(7,7)、(8,8)等不同孔径的单壁碳纳米管内的扩散,模拟表明常温下水分子在(6,6)型管内形成水分子单链,在(7,7)型管内形成相互交错的水分子双链,在(8,8)型管内形成四边形堆叠结构.模拟比较了(8,8)管中水与体相下水的扩散系数,结果显示,水在(8,8)管中的扩散系数比体相下水的扩散系数要高出两个数量级.

Molecular simulation study on the diffusion of water molecules confined in single-walled carbon nanotubes

One promising area of nanotube study is the modeling to simulate real ion channels in biological systems,which may greatly reduce the modeling complexity of ion channels. However,this can only be possible with a comprehensive understanding on the interactions of ion channels (nanotubes) with water molecules. Molecular dynamic simulations have been performed to study the structures and diffusion behavior of water molecules confined in single-walled carbon nanotubes of (6,6),(7,7),and (8,8) types. The results show that water molecules form a single chain in (6,6),twined double chains in (7,7),and quadrangular stacks in (8,8). The comparison between two diffusion coefficients of water in nanotubes and in bulk has also been made,which shows that diffusivity of water in carbon nanotubes is two orders of magnitude higher than that in bulk.