Objective molecular dynamics is used to systematically investigate elastic bending in carbon nanotubes up to 4.2 nm in diameter. A contrasting behavior is revealed: While single-wall tubes buckle in a gradual way, with a clear intermediate regime before they fully buckle, multiwalled tubes with closed cores exhibit a rate- and size-independent direct transition to an unusual wavelike mode with a 1 nm characteristic length. This rippling mode has a nearly-linear bending response and causes a ∼35% reduction in the stiffness of the thickest multiwalled tubes.
Bibliographical noteFunding Information:
We thank NSF CAREER under Grant No. CMMI-0747684 and AFOSR Grant No. FA9550-09-1-0339. Computations performed at the Minnesota Supercomputing Institute.