Molecular dynamics study of effects of sp3 interwall bridging upon torsional behavior of double-walled carbon nanotube

Atomistic simulations are performed to investigate the torsional behavior of double-walled carbon nanotubes (DWCNTs) with and without some interwall sp3 bonds subject to torsion motion. The interaction between atoms is modeled using the second-generation reactive empirical bond-order potential coupled with the Lennard-Jones potential. These results show that the critical buckling moment is increased to 97% for the ((5,5),(10,10)) DWCNT in comparison with the (10,10) SWCNT. They also indicate that the critical torsional moment and critical torsion angle of DWCNT can be obviously increased by addition of interwall sp3 coupling to provide an effective channel for load transfer of constituent outer and inner tubes. The influences of the distribution density and location of sp3 bonds on the torsional behavior of DWCNTs are also studied. For three types of distribution density, i.e., 2.63/nm, 3.68/nm and 6.84/nm, the increased magnitude of the critical torsional moments [respectively the critical torsional angles] of DWCNTs are 25.5%, 36.7% and 85.2% [respectively 32.7%, 51.9% and 103.8%]. The results also show that the torsional behavior depend strongly on the location of sp3 bonds.