Tribological properties of carbon nanotube bundles predicted from atomistic simulations

Classical molecular dynamics simulations are used to investigate the responses of bundles of single-walled carbon nanotubes to compressive and shear forces between two sliding diamond surfaces. The forces on the atoms in the simulations are determined using a many-body reactive empirical potential for hydrocarbons coupled to Lennard-Jones potentials. The simulations predict that the nanotubes can be subjected to high shear forces prior to wear because of their flexibility. The response to the applied shear forces is sliding of the bundle or a combination of sliding and rolling, where the exact responses depend on the orientation and bonding of the nanotube bundle to the sliding surfaces. No rolling of carbon nanotubes against other nanotubes in the bundle is predicted to occur in any of the orientations considered.