• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>The Journal of Chemical Physics >Ion permeation dynamics in carbon nanotubes
【24h】

Ion permeation dynamics in carbon nanotubes

机译：碳纳米管中的离子渗透动力学

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Molecular dynamics simulations are carried out to investigate the permeation of ions and water in a membrane consisting of single wall carbon nanotubes possessing no surface charges connecting two reservoirs. Our simulations reveal that there are changes in the first hydration shell of the ions upon confinement in tubes of 0.82 or 0.90 nm effective internal diameter. Although the first minimum in the g(r) is barely changed in the nanotube compared to in the bulk solution, the hydration number of Na+ ion is reduced by 1.0 (from 4.5 in bulk to 3.5 in the 0.90 nm tube) and the hydration number is reduced further in the 0.82 nm tube. The changes in the hydration shell of Cl- ion are negligible, within statistical errors. The water molecules of the first hydration shell of both ions exchange less frequently inside the tube than in the bulk solution. We compare ion trajectories for ions in the same tube under identical reservoir conditions but with different numbers of ions in the tubes. This permits investigation of changes in structure and dynamics which arise from multiple ion occupancy in a carbon nanotube possessing no surface charges. We also investigated the effects of tube flexibility. Ions enter the tubes so as to form a train of ion pairs. We find that the radial distribution profiles of Na+ ions broaden significantly systematically with increasing number of ion pairs in the tube. The radial distribution profiles of Cl- ions change only slightly with increasing number of ions in the tube. Trajectories reveal that Na+ ions do not pass each other in 0.90 nm tubes, while Cl- ions pass each other, as do ions of opposite charge. An ion entering the tube causes the like-charged ions preceding it in the tube to be displaced along the tube axis and positive or negative ions will exit the tube only when one or two other ions of the same charge are present in the tube. Thus, the permeation mechanism involves multiple ions and Coulomb repulsion among the ions plays an essential role. (c) 2006 American Institute of Physics.
机译：进行分子动力学模拟以研究离子和水在由单壁碳纳米管组成的膜中的渗透，该碳纳米管不具有连接两个储层的表面电荷。我们的模拟表明，在有效内径为0.82或0.90 nm的管中，离子的第一个水合壳存在变化。尽管与本体溶液相比，纳米管中g（r）的第一个最小值几乎没有变化，但Na +离子的水合数减少了1.0（从0.90 nm管中的体积从4.5减少到3.5）和水合数在0.82 nm的管中进一步减小了在统计误差内，Cl-离子水化壳的变化可以忽略不计。两种离子的第一水合壳中的水分子在管内的交换比在本体溶液中的交换少。我们比较了相同管在相同储层条件下，但管中离子数量不同的情况下离子的离子轨迹。这允许研究由于在不具有表面电荷的碳纳米管中多次离子占据而引起的结构和动力学变化。我们还研究了管柔韧性的影响。离子进入管子，从而形成一列离子对。我们发现，Na +离子的径向分布轮廓随着管中离子对数量的增加而显着地系统扩展。 Cl-的径向分布轮廓仅随着管中离子数量的增加而略有变化。轨迹显示，Na +离子在0.90 nm的管中不会彼此通过，而Cl-离子则通过相反电荷的离子彼此通过。进入管中的离子会导致在管中位于其前面的带相同电荷的离子沿着管轴移动，只有当管中存在一个或两个相同电荷的其他离子时，正离子或负离子才会离开管。因此，渗透机制涉及多个离子，并且离子之间的库仑排斥起着至关重要的作用。 （c）2006年美国物理研究所。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号