Effect of ultraviolet light irradiation on macroscopic single-walled carbon nanotube bundles

Abstract

We have measured the electrical conductivity and the Young modulus of macroscopic oriented ropes containing single-walled carbon nanotubes under ultraviolet (UV) irradiation. We found that UV irradiation increases both the electrical conductivity and the strength of the macroscopic bundle. These phenomena are explained by the generation of cross-links between the tubes in the macroscopic bundle due to the UV-induced interaction between the solvent dimethyl-formamide and the free radicals present on the surface of carbon nanotubes. Transmission electron microscopy investigation shows that the wall structure of nanotubes is preserved during this process, which is a valuable advantage compared to electron irradiation.