Investigation of the Mechanical Properties of Multi-Walled Carbon Nanotubes Using Density Functional Theory Calculations

Abstract

The Young’s and shear moduli of armchair and zigzag carbon nanotubes (CNTs) were calculated under axial and torsion strains using a first-principles study based on density functional theory. The results showed that the moduli of both types of single-walled CNTs (SWCNTs) decrease when tube diameter increases. We also found that the Young’s and shear moduli of armchair nanotubes are larger than those of zigzag nanotubes. Based on our first-principles calculations, the Young’s and shear moduli of double-walled CNTs (DWCNTs) are smaller than those of SWCNTs and larger than those of triple-walled CNTs. We also examined the Young’s modulus of DWCNTs with various interlayer distances and found that the Young’s modulus increases when separation wall distances decrease. Furthermore, we evaluated the effect of long-range dispersion interactions between the walls of the multi-walled CNTs, and the results show that these interactions have no significant influence on the mechanical properties of the nanotubes.