Formation behavior of single-walled carbon nanotube end-caps at high temperatures: A combined ReaxFF MD with DFT study

FC Hou and XH Wu and ZC Lin and JB Chang and X Ma and T Fang and J Sun and L Song, COMPUTATIONAL MATERIALS SCIENCE, 258, 114025 (2025).

DOI: 10.1016/j.commatsci.2025.114025

The structural evolution of single-walled carbon nanotubes (SWNTs) with different chirality at high temperatures was studied by ReaxFF molecular dynamics simulation, focusing on the formation, evolution and defect mechanism of the end-caps. Results reveal that SWNTs undergo three stages of structural evolution: local defect formation and C-C bond breakage, self-repair of sp2 carbon atoms at the end cap, and overall structural collapse. SWNTs with smaller diameters are more susceptible to local defect diffusion and bending, while larger diameter SWNTs demonstrate superior thermal stability and end cap self-repair capability. During the reconstruction of the sp2 structure, the energy barrier for transforming a 6-membered ring into a 5-membered ring is low at approximately 24.91 kcal/mol, whereas the transformation energy for other ring structures is relatively high. The interaction between alterations in the structure of SWNTs and high-temperature environments mainly manifests through stress accumulation, lattice defects, defect expansion, and cap reconstruction. These findings offer atomic insights for the advancement of high-temperature stable CNT materials.

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