INTERCALATION AND PARTIAL EXFOLIATION OF SINGLE-WALLED CARBON NANOTUBES BY NITRIC-ACID

Single-walled carbon nanotubes (SWNTs) were reacted with HNO3 solution . An expansion of the inter-nanotube spacing and increase in the amoun t of hydrogen in the material were observed by X-ray diffraction and p roton NMR measurements after the SWNTs were immersed into the HNO, sol ution for less than 2 hours. The change in diffraction pattern was rev ersible, indicating intercalation of HNO, into the SWNT bundles. When the SWNTs were immersed in the HNO, solution for a longer period of ti me, the bundles became disordered and partially exfoliated. Isolated S WNTs and large mano-particles were often observed. (C) 1998 Published by Elsevier Science B.V. All rights reserved.