Zusammenfassung
Graphyne nanotubes (GNTs) are nanostructures obtained from rolled up
graphyne sheets, in the same way carbon nanotubes (CNTs) are obtained
from graphene ones. Graphynes are 2D carbon-allotropes composed of atoms
in sp and sp(2) hybridized states. Similarly to conventional CNTs, GNTs
can present different chiralities and electronic properties. Because of
the acetylenic groups (triple bonds), GNTs exhibit large sidewall pores
that influence their mechanical properties. In this work, we studied the
mechanical response of GNTs under tensile stress using fully atomistic
molecular dynamics simulations and density functional theory (DFT)
calculations. Our results show that GNTs mechanical failure (fracture)
occurs at larger strain values in comparison to corresponding CNTs, but
paradoxically with smaller ultimate strength and Young's modulus values.
This is a consequence of the combined effects of the existence of triple
bonds and increased porosity/flexibility due to the presence of
acetylenic groups.
Nutzer