Investigation of the effects of commensurability on friction between concentric carbon nanotubes

That a commensurate contact usually leads to greater friction than an incommensurate one is a commonly held view in nanotribology. However, this perception seems paradoxical as commensurability is found to have negligible effect on the energy dissipation in double-walled carbon nanotube (DWNT) based oscillators. Using molecular dynamics simulations, we investigate such a paradox from the viewpoint of the atomic origin of friction. It is revealed that the commensurability cannot have a pronounced effect on friction unless the intertube interaction strength and the energy corrugation exceed their critical values. Both the commensurate and incommensurate oscillators constructed from natural DWNTs with an intertube distance of about 3.4 Å, may thus exhibit similar performance.