基于LAMMPS的含缺陷碳纳米管分子动力学研究

Molecular dynamics study of the carbon nanotubes containing defects on LAMMPS

碳纳米管具有结构的均匀性、简单性和材料的稳定性特点,同时也拥有与生物通道相似的输运性质,因此碳纳米管成为观察受限水分子结构、研究受限水分子动力学特性的理想材料。完美的碳纳米管在实际制备中几乎无法获得,管壁中不可避免地存在缺陷,这些缺陷会对碳纳米管的物理特性造成一定程度的影响。本文基于LAMMPS,选用一种含缺陷的碳纳米管,采用分子动力学方法模拟研究了受限体系下水分子在这种含缺陷的碳纳米管中输运的微观行为。结果表明,当相同长度的缺陷出现在管内不同位置时,扩散系数最大可相差70%以上,因此缺陷的位置对水在碳纳米管中的输运有着至关重要的影响,这对碳纳米管的制备及应用具有一定的指导意义。

Carbon nanotubes(CNTs)are characterized by structural uniformity,simplicity and material stability,as well as transport properties similar to biological channels.Therefore,CNTs have become an ideal material to observe the structure of confined water molecules and study the dynamic characteristics of restricted water molecules.Perfect carbon nanotubes are almost impossible to obtain in the actual preparation,and inevitably there are defects in the tube wall,which will affect the physical properties of carbon nanotubes to some extent.In this paper,based on LAMMPS,a kind of carbon nanotubes containing defects is selected and the microscopic behavior of water molecules transported in such nanotubes containing defects is simulated by using molecular dynamics method.The results show that when the defect of the same length appears at different positions in the tube,the maximum difference of diffusion coefficient can be more than 70%,so the location of the defect has a crucial influence on the transport of water in the carbon nanotubes,and has certain guiding significance for the preparation and application of carbon nanotubes.