High density oxidative plasma unzipping of multiwall carbon nanotubes

Abstract

We report the oxidative plasma-assisted unzipping of multiwall carbon nanotubes (MWCNTs). The exposure of oxygen plasma causes the CNTs to form initial cracks followed by the oxidation of reactive carbon species. The volatile C–O species escape and create a channel for the next oxygen molecule to diffuse into the interior of the CNT. Further oxidation results in complex C–O structures and the formation of bead like structures. These bead structures retain the strain and transform to petal like nano ribbons, releasing the excessive strain. Overall, the dimensions and morphology of the CNTs change with the two step oxidation and three step unzipping processes. The revealing of the nanostructured morphology is unique for oxygen plasma, in contrast to nitrogen and hydrogen plasma.