Theoretical modeling relating to temperature and cap/end for carbon nanotubes under hydrostatic pressure

In this paper, based on the molecular mechanics coupled with an atomistic-based molecular mechanics theory, the equivalent elastic moduli of temperature-dependence for single walled carbon nanotubes are analyzed. Under a hydrostatic pressure, two types of carbon nanotubes with the closed-end and the open-end are considered, respectively, and the difference between bulk modulus and transverse/radial modulus of these nanotubes is also assessed. The present results show that the bulk modulus and transverse modulus of single-walled carbon nanotubes are very sensitive to the temperature and end states. Whether having end caps or not, the bulk modulus and radial modulus of carbon nanotubes vary with the external hydrostatic pressure, and they decrease with the increase of the tube diameter and the ambient temperature. However, the circumferential modulus increases with the increase of nanotube diameters. With the increase of temperatures, the bulk modulus and transverse modulus become insensitive to the diameters.