Theoretical variations in the Young's modulus of single-walled carbon nanotubes with tube radius and temperature: a molecular dynamics study

This study uses molecular dynamics simulations to investigate the intrinsic thermal vibrations of a single-walled carbon nanotube (SWNT) modelled as a clamped cantilever. Using an elastic model defined in terms of the tube length, the tube radius and the tube temperature, the standard deviation of the vibrational amplitude of the tube's free end is calculated and the Young's modulus of the SWNT evaluated. The numerical results reveal that the value of the Young's modulus is independent of the tube length, but decreases with increasing tube radius. At large tube radii, the Young's modulus value approaches the in-plane modulus of graphene, which can be regarded as an SWNT of infinitely large radius. The results also indicate that the Young's modulus is insensitive to changes in the tube temperature at temperatures of less than approximately 1100 K, but decreases significantly at higher temperatures.