Effect of Chemical Treatment on the Dispersion Properties of Carbon Nanotubes

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.