Role of intertube spacing in the pullout forces of double-walled carbon nanotubes

The finite element method is combined with the modified Morse interatomic potential in order to study the role of intertube spacing in the pullout forces of armchair and zigzag double-walled carbon nanotubes. The van der Waals forces between the adjacent tubes are simulated using the ‘6–12’ Lennard-Jones potential. The intertube spacing ranges from 0.34 to 0.5 nm. The results show a significant decrease of pullout forces with increasing the intertube spacing in both types of double-walled carbon nanotubes.