How does a carbon nanotube grow? An in situ investigation on the cap evolution.
Catalyst-free inner growth of single-wall carbon nanotubes has been directly realized and monitored by means of in situ high-resolution transmission electron microscopy, with particular attention paid to the evolution of the cap shape. The cap of a carbon nanotube is surprisingly found to be kept closed during the growing/shrinking process, and the cap shape evolves inhomogeneously with a few particular sites growing faster during the growth, while the cap of a carbon nanotube keeps a round shape during the shrinkage process. The closed cap should be specific for noncatalytic growth of carbon nanotubes. We infer, from the results above, the possible atomistic mechanism and how the carbon network can accommodate or release the carbon atoms during the growth/shrinkage of carbon nanotubes.
Jin
Chuanhong
C
Nanotube Research Center, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba 305-8565, Japan. chuanhong-jin@aist.go.jp
Suenaga
Kazu
K
Iijima
Sumio
S
D003198:Computer Simulation; D003460:Crystallization / Q000379:methods*; D046911:Macromolecular Substances / Q000737:chemistry; D008422:Materials Testing; D046529:Microscopy, Electron, Transmission / Q000379:methods*; D008956:Models, Chemical; D008958:Models, Molecular; D008968:Molecular Conformation; D036103:Nanotechnology / Q000379:methods*; D037742:Nanotubes, Carbon / Q000737:chemistry* / Q000648:ultrastructure*; D010316:Particle Size; D013499:Surface Properties
D046911:Macromolecular Substances; D037742:Nanotubes, Carbon