Nanohinge-induced plasticity of helical carbon nanotubes.

Helical carbon nanotubes with intentionally incorporated non-hexagonal defects have unexpectedly high toughness and plasticity, in addition to the well-recognized extreme elasticity. The obtained toughness approaches 5000 J g(-1) with decreasing spring radius. The high toughness originates from the plastic nanohinge formation as a result of distributed partial fractures. A strong spring size effect, contradictory to the continuum solution, is precisely described by an atomistic bond-breaking model.