Atomistic Simulations of the Mechanical Properties of 'Super' Carbon Nanotubes

TL;DR

This study uses molecular dynamics simulations to explore the mechanical properties of 'super' carbon nanotubes, revealing their unique behavior, dependence on chirality and radius, and potential for advanced material applications.

Contribution

It introduces a detailed simulation analysis of 'super' carbon nanotubes' mechanical behavior, including their fracture process and scaling laws for hierarchical structures.

Findings

Young's modulus depends on chirality and inversely on radius.

STs exhibit net-like tensile behavior similar to fishing nets.

Junctions significantly influence fracture in small-radius STs.

Abstract

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.