Crash Simulation Of Single-walled Carbon Nanotubes And Graphene Sheet

The discovery of carbon nanotubes by Iijima in 1991 initiated rapid progress in the field of carbon nanotechnology. Carbon nanotubes are formed by the seamless rolling of one or several graphite sheets over themselves. Carbon nanotubes include muti-walled carbon nanotubes and single-walled carbon nanotubes. Carbon nanotubes may be an particular material being used in many fields for their quasi-one-dimensional structure, rigidity and other special physical and chemical peculiarities.In the paper, the collision of a single-walled carbon nanotube with two graphitic patches has been simulated by tight-binding molecular dynamics (TBMD) method. In the simulation, the SWCNT was positioned between of two graphitic patches and some certain initial kinetic energy was added on the left patch to let it move towards the middle SWCNT and collide with the SWCNT and then with the right patch. From calculation results, we can conclude as follows: (1) It is a resilient collision when a SWCNT was impacted by graphitic patch with some certain initial kinetic energy, the C-C bond can not be destroyed under this energy; (2) When a SWCNT with small radius positioned between of two graphitic patches with proper size, certain energy and temperature conditions can make two patches to arch in opposite direction so that the dangling bonds at edges of two patches closed enough to bonding and formed a new tubular structure surround the SWCNT; and further produced a double-walled carbon nanotube for a while; (3) The chirality of produced outer tube completely only depend on the relative direction of the two patches and is irrelevant to the chirality of inner single-walled carbon nanotube. Moreover, the size of the outer tube rely on the sizes of graphitic patches completely; (4) The produced double-walled carbon nanotube is not a stable structure, its C-C bonds of inner tube will break to release strain energy, then many small carbon clusters such as C atoms, C₂ dimers, C₃ trimers fly off along axis direction of outer tube towards two ends of the tube and captured by dangling bond at two ends. These successive processes made outer tube growth and finally result in a stable closed single-walled carbon nanotube with a larger radius. This may be a kind of growth mechanism that a single-walled carbon nanotube with small radius how to convert to a single-walled carbon nanotube with larger radius;...