Linear and spiral forms of longitudinal cuts in graphitized N-doped multiwalled carbonnanotubes (g-N-MWCNTs)

Abstract

Nitrogen-containing multiwalled nanotubes (N-MWCNTs), formed by CVD from anitrogen-containing feedstock have a ‘bamboo’ structure in which the axes of the grapheneplanes are not parallel to the axis of the nanotube and the core is periodically bridged. Wefind that thermal and chemical treatment of these materials can produce nanotubes thathave been cut longitudinally in either a linear or in a spiral manner. In addition, theselongitudinally cut nanotubes can be partially or fully unrolled by sonication in anaqueous surfactant, producing graphite platelets as well as narrow structuresthat could be thin graphite ribbons or very narrow, intact N-MWCNTs. Thesedifferent morphologies of graphite, available from one source, suggest that there aremultiple structures of N-MWCNTs present, few as simple as stacked cups or nestedscrolls.