Simulation of mechanical properties of carbon nanotubes with superlattice structure

The effect of radius and layer thickness on the mechanical properties of carbon nanotubes with 'zigzag-armchair-zigzag' superlattice structure (CNTSS) is investigated using molecular dynamics simulation method. The interactions between carbon atoms are modeled using the second-generation reactive empirical bond-order Brenner potential coupled with the Lennard-Jones potential. The results indicate that the Young's modulus of CNTSS shows a significant dependence on its radius and layer thickness. In contrast, the critical stress is insensitive to the layer thickness and radius of CNTSS. And the critical stress of CNTSS is close to that of its thicker carbon nanotubes segment. In addition, the damage modes of CNTSS depend on the connecting region due to the presence of 5-7 defects and the energy early concentrating in the junctions. The effects of the number of junctions on the mechanical properties of CNTSS are also discussed. The results indicate that the joints made in this way still have relatively high mechanical properties corresponding to that of the ideal single-walled carbon nanotube.