Axial Stiffness of Multiwalled Carbon Nanotubes

TL;DR

This paper investigates the axial stiffness of multiwalled carbon nanotubes (MWCNTs), revealing it depends mainly on a few outer shells due to van der Waals interactions, with a formula relating stiffness to radius and elongation.

Contribution

It provides a new understanding of MWCNT axial stiffness dependence and derives an interpolating formula based on radius and elongation.

Findings

Stiffness is mainly determined by 3-5 outer shells.

Inverse relation between radius and Young's modulus observed.

Derived formula links axial stiffness with radius and elongation.

Abstract

The axial stiffness of MWCNTs is demonstrated to be determined only by several external shells (usually 3-5 and up to 15 for the extremely large nanotubes and high elongations) what is in a good agreement with experimentally observed inverse relation between the radius and Young modulus (i.e., stiffness) of MWCNTs. This result is a consequence of the van der Waals intershell interaction. The interpolating formula is obtained for the actual axial stiffness of MWCNT as a function of the tube external radius and elongation.