Fabrication of stable dispersions containing up to 70% individual carbon nanotubes in a common organic solvent

Applications of single-wall carbon nanotubes (SAINT) are severely restricted, as they exist in rope-like bundles. Many methods have been suggested to de-bundle SWNTs, including both covalent and noncovalent funtionalisation with surfactants, acids, polymers and macromolecules. However, these strategies are unsatisfactory because they result in either the chemical modification of the nanotube or the presence of residual dispersion agents. What is required is the demonstration of stable, exfoliated SWNT dispersions in common solvents. In. this work we have demonstrated debundling of single-wall nanotubes by diluting nanotubes dispersions in the solvent N-methyl-2-pyrrolidinone (NMP). Atomic-force-microscopy measurements show a steady decrease in bundle diameter distribution as the concentration is decreased. Photoluminescence and Raman spectroscopy confirmed the presence of individual nanotubes in NMP dispersion.