Mechanics of C₆₀ in nanotubes

A modeling study of C₆₀ in nanotubes is presented, with focus on a new approach. We report on the elastic properties, energetics, and certain tribological issues, for C₆₀ inside (n, n) nanotubes, with n ranging from 5 to 10. A new combined molecular dynamics/continuum approach with account of both the nonbonded and bonded interactions was used. The elastic properties of the nanotube were analytically derived on the basis of the Tersoff-Brenner potential. The derived Young's modulus is consistent with experimental values. We have computed the case where the C₆₀ has zero initial velocity and is "sucked" into the (10, 10) or (9, 9) tubes due to the sharp force gradient present from the deep attractive potential at the tube inlet; C₆₀ then oscillates back and forth inside the (10, 10) and (9, 9) nanotubes. C₆₀ seems to make a perfect nanobearing system when in the (10, 10) tube. In a separate modeling study, C₆₀ was fired on axis at high velocity (from 400 up to 1600 m/s) toward the six different armchair nanotubes. Over this velocity range the C₆₀ could only penetrate into the (10, 10) and (9, 9) nanotubes, rebounding from the (8, 8), (7, 7), (6, 6), and (5, 5) tubes.