分子动力学模拟研究纳米孔道中受限水的自扩散

The study on the self-diffusion of water confined in nanotubes by molecular dynamics simulations

利用分子动力学模拟技术考察受限于3种不同材料的纳米孔道(单壁碳管、硼氮管、铁原子孔道)中水分子的静态结构与扩散动力学,计算孔道中水分子沿轴向的自扩散系数Dz,讨论孔道截面尺寸、形状以及组成材料的变化对水分子扩散动力学的影响.结果表明,水分子的轴向自扩散系数随孔道半径的增大而减小,光滑的孔道壁有利于水分子的运输.在3种孔道限制体中,水分子在单壁碳纳米管内的自扩散系数最大.

The structures and dynamics of water confined in three nanotubes（single-wall carbon nanotube,boron nitride nanotube,iron-atom nanotube） were studied by molecular dynamics simulation.The self-diffusion coefficient for water along Z-axis（Dz） is calculated.The effect of the sizes and shapes of nanotube as well as the material of tube-wall on the water transport were discussed.The results show that Dz decreases as the radius of tube increases,while the more smooth the tube-wall,the faster water moves inside the tube.For the three confined systems,the self-diffusion coefficient is the biggest for water confined in single-wall carbon nanotube.