  The mechanical properties of the so-called `super' carbon nanotubes (STs) are
investigated using classical molecular dynamics simulations. The STs are built
from single walled carbon nanotubes (SWCNTs) connected by Y-like junctions
forming an ordered carbon nanotube network that is then rolled into a seamless
cylinder. We observed that the ST behavior under tensile tests is similar to
the one presented by fishing nets. This interesting behavior provides a way to
vary the accessible channels to the inner parts of STs by applying external
mechanical load. The Young's modulus is dependent on the ST chirality and it
inversely varies with the ST radius. Smaller reduction of breaking strain
values due to temperature increase is predicted for zigzag STs compared to
SWCNTs. The results show that, for STs with radius ~ 5 nm, the junctions
between the constituent SWCNTs play an important role on the fracture process.
The Young's modulus and tensile strength were estimated for hierarchical
higher-order STs using scaling laws related to the ST fractal dimension. The
obtained mechanical properties suggest that STs may be used in the development
of new porous, flexible, and high-strength materials.
