Selectivity of chemical oxidation attack of single-wall carbon nanotubes in solution

Chemical oxidation of single wall carbon nanotubes (SWNTs), produced with the HiPco method, is studied by resonance Raman scattering. The analysis of the radial breathing mode makes it possible to assign the observed bands to metallic and semiconducting SWNTs and to suggest the chiral indices of SWNTs contributing to the spectra. On this basis we observe that the most important parameter which determines the attack of the nanotubes is their diameter: Small diameter tubes, due to the stress induced by the curvature, are first attacked and destroyed. Some reactivity is also observed for larger diameter metallic nanotubes, which, however, are not easily destroyed.