Sonication-assisted functionalization and solubilization of carbon nanotubes

Carbon nanotubes were solubilized via functionalization with poly(propionylethylenimine-co-ethylenimine). The diimide-activated amidation reaction for the functionalization was found to be significantly improved in both efficiency and yield by sonication under ambient conditions. It was also found that depending on the duration of sonication the nanotubes were shortened to different lengths in the functionalization reactions. The method allows relatively efficient preparation of solubilized carbon nanotubes of potentially a selectable average length.