提高水分子流出纳米碳管速度的特殊水分子偶极排布研究  

Water Molecules Exiting a Carbon Nanotube Driven by Special Water Dipole Orientations

作　　者：亓文鹏[1,2] 涂育松[3] 万荣正[2] 方海平[1,2] 

机构地区：[1]山东大学物理学院,济南250100 [2]中国科学院上海应用物理研究所,上海201800 [3]上海大学系统生物学研究所,上海200444

出　　处：《应用数学和力学》2011年第9期1030-1036,共7页Applied Mathematics and Mechanics

基　　金：国家自然科学基金资助项目(10825520);上海市教委科研创新资助项目(11YZ20)

摘　　要：使用分子动力学的方法,研究了水分子进出狭窄碳纳米管的过程.发现管口处水分子的偶极垂直于碳管时容易流出碳管.根据碳管中与之相邻的水分子的偶极方向可以把这种特殊构型分为2类.虽然,这2类特殊结构的出现概率非常小,但是它们对净流过碳管水分子的贡献与其它结构的贡献基本相同.这2种偶极排布中水分子比较接近管壁、远离Lennard-Jones势的平衡位置,导致这2种偶极排布中水分子能量升高,处于相对不稳定的状态,容易流出碳管.这个发现表明可以通过调控碳纳米管内的水分偶极方向控制管内的水分子流动.One-dimensional ordered water molecules entering and exiting a carbon nanotube with appropriate radius were studied by molecular dynamics simulations. It was found that a water molecule near the nanotube end was more likely to be expelled from the nanotube if its dipole was almost aligned perpendicular to the nanotube axis. The key to this observation is that those water molecules are closer to the wall of nanotube away from the equilibrium posi- tion of Lennar-Jones potential, so that the interaction energy for those water molecules is rela- tively high. There are two particular structures of the perpendicular water depending on the di- pole direction of the adjacent water molecule in the nanotube. Although the probabilities of these structures are quite small, their contributions to the net flux across the nanotube end are approximately equal to the predominant structures. The findings show the possibility of controlling the water flow by regulating the dipole directions of water molecules inside the nanochannels.

关 键 词：水 纳米碳管 单行水链 LENNARD-JONES势 

分 类 号：O352[理学—流体力学]