Abstract:

The molecular dynamics method was used to investigate the elastic properties of armchair and zigzag single-walled carbon nanotubes grafted by carboxyls on their ports. The results showed that the Young’s moduli of ungrafted armchair (5, 5), (10, 10) and zigzag (9, 0) , (18, 0) single-walled carbon nanotubes were 948, 901 GPa and 804, 860 GPa, respectively. When the single-walled carbon nanotubes were grafted by 2 to 8 carboxylic functional groups, the Young’s modulus of the armchair single-walled carbon nanotubes had few varieties, while the zigzag single-walled carbon nanotubes were different, namely, the Young’s modulus of the nanotubes decreased significantly due to the grafting and the Young’s modulus increased appreciably with increasing of the grafts. The reasons were analyzed in terms of the isoline structure of deformation electron density, the bond-length and the system potential energy varieties of the carbon nanotubes with different graft numbers.

Key words: Carbon nanotubes, Molecular dynamics, Effects of grafts, Carboxyl, Young’s modulus