Van der Waals energy surface of a carbon nanotube sheet

The van der Walls interaction between a carbon nanotube sheet (CNTS) and a rare gas atom, is studied using both atomistic and continuum approaches. We present analytical expressions for the van der Waals energy of continuous nanotubes interacting with a rare gas atom. It is found that the continuum approach does not properly treat the effect of atomistic configurations on the energy surfaces. The energy barriers are small as compared to the thermal energy, which implies the free motion above the CNTS in heights about one nanometer. In contrast to the energy surface of a graphene sheet, the honeycomb lattice structure in the energy surface of a CNTS is imperceivable. Defects alter the energy surface which therefore influence the gas adsorption mechanism.

► Zigzag CNTS cause different periodicities in the energy surfaces.
► The energy barriers decrease rapidly with height.
► Defects disturb the periodicity of the energy surface.
► Defects reduce the barriers and change the gas adsorption.
► The honeycomb lattice feature does not appear in the energy surfaces of CNTS.