Abstract: The chemical oxidation in a mixture of concentrated acids was used to modify carbon nanotubes (CNTs). After treatment, stable homogeneous dispersions of CNTs
were prepared. It was found by FTIR that the improvement of dispersibility should be due to the carboxyl groups and hydroxyl groups on the surface of modified CNTs.
ζ potential measurements showed that the ionization of acidic surface groups led to a higher density of negative charge. TEM indicated that the CNTs were less
twisted after treatment. The measurements of effective diameter and sediment percent further confirmed that the modified CNTs suspension had higher dispersibility and stability.

Key words: carbon nanotubes, chemical treatment, dispersion