Molecular mechanics investigations of carbon nanotube and graphene sheet interaction

The interaction between a carbon nanotube (CNT) and a graphene sheet is investigated to describe the contact properties between a CNT atomic force microscope (AFM) tip and a graphite surface. The energy of the whole system is calculated using MM+ molecular mechanical modeling. With the numerical calculations, one explores the sliding motion of the CNT on the graphene sheet either at the CNT apex or with a given CNT length contacting the surface. The aim is to mimic the AFM CNT tip scanning a graphite surface. To do so we calculate the energy barriers, the tips have to overcome to achieve a full translation. The results show that the barrier heights markedly depend on the contact length between the CNT and the graphene but show a weak dependence, if any, on the CNT tube diameter.