Hydrothermal functionalisation of single-walled carbon nanotubes

Chemical functionalisation of single-walled carbon nanotubes (SWNTs) has been achieved by hydrothermal treatment (HT) in aqueous acidic solutions. Depending on the type of acid chlorine, bromine or sulphur could be attached to the conjugated pi-system. Apart from the well known effects of acid oxidation, X-ray and ultraviolet photoemission spectroscopy suggest that the halides are introduced at structurally/electronically disordered defect sites. Sulphur is incorporated in higher density, probably in a similar fashion as oxygen. HT thus provides an efficient tool to functionalise SWNTs and paves the way for new SWNT materials and synthetic routes in various polar media and electrolytes. (C) 2003 Elsevier B.V. All rights reserved.