Purification, Cutting, and Sidewall Functionalization of Multiwalled Carbon Nanotubes Using Potassium Permanganate Solutions

In this work multiwalled carbon nanotubes were examined using a combination of thermal annealing followed by chemical treatments with potassium permanganate solution. Functionalization with carboxylic acid moieties through this newly devised process simultaneously purified and cut the nanotubes. A cutting procedure using potassium permanganate that could keep or remove the MnO 2 has not been previously reported, making this study a stepping stone to further functionalization/application opportunities. One such further functionalization was explored here with alkyl groups, through the generation of an amide linkage. A very detailed standard suspension test was performed on this material. What was found was an increased suspension stability toward polar solvents for the nanotubes with high concentrations of MnO 2 deposits, and in nonpolar solvents the nanotubes with large alkyl chains attached were observed, thus proving it to be a versatile treatment.