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Comment on "Mechanism for superelongation of carbon nanotubes at high temperatures".
| Content Provider | Semantic Scholar |
|---|---|
| Author | Ding, Feng Huang, Jian Yu Yakobson, Boris I. |
| Copyright Year | 2009 |
| Abstract | Recently Tang et al. [1] reported a molecular dynamics (MD) simulation of carbon nanotube (CNT) elongation, with numerous topological defects generated. They interpret this as a more realistic superplasticity mechanism than the pentagon-heptagon pair (5j7) glide and climb [2,3]. Although the extensive MD computations do display some interesting detail, it is important to explain how the conditions and the physics of simulated relaxation are rather different than observed in reality [4,5]. In experiments, the length L increased by 100%–280% nearly uniformly and flawlessly, which was justly called superplasticity [4,5]: except a few moving kinks, no disorder was observed. In contrast, in MD simulations [1] ‘‘Hundreds of defects are activated and widely distributed over almost the entire tube,’’ which soon necks off and fails. The structural relaxation consists mainly of C-C bond rotation flips [Stone-Wales (SW) transformations] known to dominate the formation and mobility of defects in the sp carbon network [6]. In a pristine unstrained CNT or graphene, the SW defect has positive formation energy ESW. Under tension, ESW lowers as the bond flip reduces the elastic strain. This lattice strain " and the initial bond orientation angle control the ESW [7]: ESWð ; "Þ 1⁄4 2:7 3:9" 32" cosð2 Þ: (1) |
| Starting Page | 33 |
| Ending Page | 53 |
| Page Count | 21 |
| File Format | PDF HTM / HTML |
| DOI | 10.1103/PhysRevLett.103.039601 |
| PubMed reference number | 19659329 |
| Journal | Medline |
| Volume Number | 103 |
| Issue Number | 3 |
| Alternate Webpage(s) | http://www.owlnet.rice.edu/~biy/Selected%20papers/09PRL_relax.pdf |
| Alternate Webpage(s) | https://doi.org/10.1103/PhysRevLett.103.039601 |
| Journal | Physical review letters |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
