Snapshots of the Fragmentation for C70@Single-Walled Carbon Nanotube: Tight-Binding Molecular Dynamics Simulations

In previously reported experimental studies, a yield of double-walled carbon nanotubes (DWCNTs) at C-70@Single-walled carbon nanotubes (SWCNTs) is higher than C-60@SWCNTs due to the higher sensitivity to photolysis of the former. From the perspective of pyrolysis dynamics, we would like to understand whether C-70@SWCNT is more sensitive to thermal decomposition than C-60@SWCNT, and the starting point of DWCNT formation, which can be obtained through the decomposition fragmentation of the nanopeapods, which appears in the early stages. We have studied the fragmentation of C-70@SWCNT nanopeapods, using molecular dynamics simulations together with the empirical tight-binding total energy calculation method. We got the snapshots of the fragmentation structure of carbon nano-peapods (CNPs) composed of SWCNT and C-70 fullerene molecules and the geometric spatial positioning structure of C-70 within the SWCNT as a function of dynamics time (for 2 picoseconds) at the temperatures of 4000 K, 5000 K, and 6000 K. In conclusion, the scenario in which C-70@SWCNT transforms to a DWCNT would be followed by the fragmentation of C-70, after C-70, and the SWCNT have been chemically bonding in the early stages. The relative stability of fullerenes in CNPs could be reversed, compared to the ranking of the relative stability of the encapsulated molecules themselves.

Automated summary

The study reveals that C-70@SWCNT nanopeapods may be more sensitive to thermal decomposition at high temperatures than C-60@SWCNT, and the formation of double-walled carbon nanotubes may start with the fragmentation of C-70 within the SWCNT structure.