Water Molecules Exiting a Carbon Nanotube Driven by Special Water Dipole Orientations
-
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.
-
关键词:
- 水 /
- 纳米碳管 /
- 单行水链 /
- Lennard-Jones势
Abstract: 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 position of Lennar-Jones potential,so that the interaction energy for those water molecules is relatively high.There are two particular structures of the perpendicular water depending on the dipole 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.-
Key words:
- water /
- carbon nanotube /
- single-file water chain /
- Lennard-Jones (LJ) interaction
-
[1] Pan Z W, Xie S S, Chang B H, Wang C Y, Lu L, Liu W, Zhou M Y, Li W Z. Very long carbon nanotubes[J]. Nature, 1998, 394(6694): 631-632. doi: 10.1038/29206 [2] Hummer G, Rasaiah J C, Noworyta J P. Water conduction through the hydrophobic channel of a carbon nanotube[J]. Nature, 2001, 414(6860): 188-190. doi: 10.1038/35102535 [3] Cambre S, Schoeters B, Luyckx S, Goovaerts E, Wenseleers W. Experimental observation of single-file water filling of thin single-wall carbon nanotubes down to chiral index (5,3)[J]. Physical Review Letters, 2010, 104(20): 207401. doi: 10.1103/PhysRevLett.104.207401 [4] Fang H P, Wan R Z, Gong X J, Lu H J, Li S Y. Dynamics of single-file water chains inside nanoscale channels: physics, biological significance and applications[J]. Journal of Physics D—Applied Physics, 2008, 41(10): 16. [5] Wan R Z, Fang H P. Water transportation across narrow channel of nanometer dimension[J]. Solid State Communications, 2010, 150(21/22): 968-975. doi: 10.1016/j.ssc.2010.01.016 [6] de Groot B L, Grubmuller H. Water permeation across biological membranes: mechanism and dynamics of aquaporin-1 and GlpF[J]. Science, 2001, 294(5550): 2353-2357. doi: 10.1126/science.1062459 [7] Tajkhorshid E, Nollert P, Jensen M O, Miercke L J W, O’Connell J, Stroud R M, Schulten K. Control of the selectivity of the aquaporin water channel family by global orientational tuning[J]. Science, 2002, 296(5567): 525-530. doi: 10.1126/science.1067778 [8] Wan R Z, Li J Y, Lu H J, Fang H P. Controllable water channel gating of nanometer dimensions[J]. Journal of the American Chemical Society, 2005, 127(19): 7166-7170. doi: 10.1021/ja050044d [9] Rasaiah J C, Garde S, Hummer G. Water in nonpolar confinement: from nanotubes to proteins and beyond[J]. Annual Review of Physical Chemistry, 2008, 59: 713-740. doi: 10.1146/annurev.physchem.59.032607.093815 [10] Koga K, Gao G T, Tanaka H, Zeng X C. Formation of ordered ice nanotubes inside carbon nanotubes[J]. Nature, 2001, 412(6849): 802-805. doi: 10.1038/35090532 [11] Allen R, Melchionna S, Hansen J P. Intermittent permeation of cylindrical nanopores by water[J]. Physical Review Letters, 2002, 89(17): 175502. doi: 10.1103/PhysRevLett.89.175502 [12] Berezhkovskii A, Hummer G. Single-file transport of water molecules through a carbon nanotube[J]. Physical Review Letters, 2002, 89(6): 064503. doi: 10.1103/PhysRevLett.89.064503 [13] Beckstein O, Sansom M S P. Liquid-vapor oscillations of water in hydrophobic nanopores[J]. Proceedings of the National Academy of Sciences of the United States of America, 2003, 100(12): 7063-7068. doi: 10.1073/pnas.1136844100 [14] Jensen M O, Tajkhorshid E, Schulten K. Electrostatic tuning of permeation and selectivity in aquaporin water channels[J]. Biophysical Journal, 2003, 85(5): 2884-2899. doi: 10.1016/S0006-3495(03)74711-0 [15] Zhu F Q, Tajkhorshid E, Schulten K. Pressure-induced water transport in membrane channels studied by molecular dynamics[J]. Biophysical Journal, 2002, 83(1): 154-160. doi: 10.1016/S0006-3495(02)75157-6 [16] Majumder M, Chopra N, Andrews R, Hinds B J. Nanoscale hydrodynamics—enhanced flow in carbon nanotubes[J]. Nature, 2005, 438(7064): 44. doi: 10.1038/438044a [17] Li J Y, Gong X J, Lu H J, Li D, Fang H P, Zhou R H. Electrostatic gating of a nanometer water channel[J]. Proceedings of the National Academy of Sciences of the United States of America, 2007, 104(10): 3687-3692. doi: 10.1073/pnas.0604541104 [18] Joseph S, Aluru N R. Why are carbon nanotubes fast transporters of water?[J]. Nano Letters, 2008, 8(2): 452-458. doi: 10.1021/nl072385q [19] Tu Y S, Xiu P, Wan R Z, Hu J, Zhou R H, Fang H P. Water-mediated signal multiplication with Y-shaped carbon nanotubes[J]. Proceedings of the National Academy of Sciences of the United States of America, 2009, 106(43): 18120-18124. doi: 10.1073/pnas.0902676106 [20] Zhao J O, Huang J Q, Wei F, Zhu J. Mass transportation mechanism in electric-biased carbon nanotubes[J]. Nano Letters, 2010, 10(11): 4309-4315. doi: 10.1021/nl1008713 [21] Bonthuis D J, Horinek D, Bocquet L, Netz R R. Electrohydraulic power conversion in planar nanochannels[J]. Physical Review Letters, 2009, 103(14): 144503. doi: 10.1103/PhysRevLett.103.144503 [22] Waghe A, Rasaiah J C, Hummer G. Filling and emptying kinetics of carbon nanotubes in water[J]. Journal of Chemical Physics, 2002, 117(23): 10789-10795. doi: 10.1063/1.1519861 [23] Wan R Z, Lu H J, Li J Y, Bao J D, Hu J, Fang H P. Concerted orientation induced unidirectional water transport through nanochannels[J]. Physical Chemistry Chemical Physics, 2009, 11(42): 9898-9902. [24] Gong X J, Li J Y, Lu H J, Wan R Z, Li J C, Hu J, Fang H P. A charge-driven molecular water pump[J]. Nature Nanotechnology, 2007, 2(11): 709-712. doi: 10.1038/nnano.2007.320 [25] Parrinello M, Rahman A. Polymorphic transitions in single-crystals: a new molecular-dynamics method[J]. Journal of Applied Physics, 1981, 52(12): 7182-7190. doi: 10.1063/1.328693 [26] Nose S. A unified formulation of the constant temperature molecular-dynamics methods[J]. Journal of Chemical Physics, 1984, 81(1): 511-519. doi: 10.1063/1.447334 [27] Hoover W G. Canonical dynamics: equilibrium phase-space distributions[J]. Physical Review A, 1985, 31(3): 1695-1697. doi: 10.1103/PhysRevA.31.1695 [28] Hess B, Kutzner C, van der Spoel D, Lindahl E. GROMACS 4: algorithms for highly efficient, load-balanced, and scalable molecular simulation[J]. Journal of Chemical Theory and Computation, 2008, 4(3): 435-447. doi: 10.1021/ct700301q [29] Jorgensen W L, Chandrasekhar J, Madura J D, Impey R W, Klein M L. Comparison of simple potential functions for simulating liquid water[J]. Journal of Chemical Physics, 1983, 79(2): 926-935. doi: 10.1063/1.445869 [30] Xiu P, Zhou B, Qi W P, Lu H J, Tu Y S, Fang H P. Manipulating biomolecules with aqueous liquids confined within single-walled nanotubes[J].Journal of the American Chemical Society, 2009, 131(8): 2840-2845. doi: 10.1021/ja804586w [31] Wang C L, Lu H J, Wang Z G, Xiu P, Zhou B, Zuo G H, Wan R Z, Hu J, Fang H P. Stable liquid water droplet on a water monolayer formed at room temperature on ionic model substrates[J]. Physical Review Letters, 2009, 103(13): 4.
点击查看大图
计量
- 文章访问数: 1383
- HTML全文浏览量: 95
- PDF下载量: 1126
- 被引次数: 0