Radial collapse of carbon nanotubes without and with Stone–Wales defects under hydrostatic pressure

Abstract

The effects of carbon nanotube (CNT) chirality, Stone–Wales (SW) defects and defect orientation on the radial collapse and elasticity of single-walled CNTs (SWNTs) were investigated using molecular mechanics and molecular dynamics (MD) simulations. It is found that the collapse pressure (P_c) of the armchair SWNT is 13.75 times higher than that of the zigzag SWNT. Moreover, the armchair SWNT with SW defects is easier to collapse compared to the intrinsic armchair SWNT, while the zigzag SWNT with SW defects is more difficult to collapse compared to the intrinsic zigzag SWNT; the SW² defect makes P_c of SWNT (10, 10) decrease by 11.0%, while the SW⁴ defect makes P_c of SWNT (17, 0) increase by 100.0%. We introduce a model for SWNTs deformed in the radial direction according to the projection of the C–C bond along the bending direction. The model is validated for defect-free SWNTs and is then used to study the radial collapse of SWNTs with SW defects. The effect of chirality and SW defect on the radial collapse of SWNTs can be understood by the model. The strong sensitivity of radial collapse of SWNTs to chirality and SW defect can provide some guidance for high load structural applications of SWNTs.