We have shown that the mechanics of single-wall carbon nanotubes cannot be assimilated to the one of macroscopic tubes. At the meso-nanoscale, the continnuum mechanics approach breaks and needs to be replaced by an atomistic view. Our combined experimental and theoretical study, has allowed us to determine a correction to the Lévy-Carrier law (continuum mechanics) to describe the radial collapse of tubes under pressure. Our modified formula allows us to the predict that the smallest stable free-standin nanotube has a diameter of 0.44 nm. A result in excellent agreement with experimental studies. In addition we obain a very precise value of the bednding stiffness of graphene of .

This work is a collaboration with colleagues from universities in UK, Germany, Austria and Brazil,

More information in this link:

From mesoscale to nanoscale mechanics in single-wall carbon nanotubes
A. Torres-Dias et al., Carbon 123, 145 (2017)