Tunvir Kazi, Kim Amkee, Nahm Seung Hoon
Division of Metrology for Quality Life, Korea Research Institute of Standards and Science, 1 Doryong Dong, Yuseong-Gu, Daejeon 305-340, Republic of Korea.
Nanotechnology. 2008 Feb 13;19(6):065703. doi: 10.1088/0957-4484/19/6/065703. Epub 2008 Jan 23.
The tensile behavior of single-walled nanotubes (SWNTs) having two defects (vacancy or Stone-Wales) positioned next to each other was simulated in this study to investigate the influence of the spatial arrangement of defects on the mechanical properties. The simulations were performed using classical molecular dynamics (MD) at the atomic scale. Two neighboring vacancy defects reduced the failure strength as much as 46% and the failure strain as much as 80% in comparison with those of pristine SWNTs, while two neighboring Stone-Wales defects reduced them as much as 34% and 70% respectively. SWNTs having two defects in the loading (axial) direction showed higher failure strength than SWNTs with defects perpendicular to the loading direction. For both types of defect, the closer the defects, the weaker the SWNTs. As result, the defect arrangement in the SWNT structure must be one of the key factors in determining its mechanical properties, as well as the population of defects.
本研究模拟了具有两个相邻缺陷（空位或斯通-威尔士缺陷）的单壁纳米管（SWNT）的拉伸行为，以研究缺陷的空间排列对其力学性能的影响。模拟是在原子尺度上使用经典分子动力学（MD）进行的。与原始单壁纳米管相比，两个相邻的空位缺陷使破坏强度降低了46%，破坏应变降低了80%，而两个相邻的斯通-威尔士缺陷分别使破坏强度和破坏应变降低了34%和70%。在加载（轴向）方向上有两个缺陷的单壁纳米管比垂直于加载方向有缺陷的单壁纳米管具有更高的破坏强度。对于这两种类型的缺陷，缺陷越靠近，单壁纳米管越弱。因此，单壁纳米管结构中的缺陷排列以及缺陷数量必定是决定其力学性能的关键因素之一。
