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

In this work multi-walled carbon nanotubes were examined using a combination of thermal annealing followed by chemical treatments with potassium permanganate solution. Functionalisation with carboxylic acid moieties through this newly devised process simultaneously purified and cut the nanotubes. A cutting procedure using potassium permanganate has not been previously reported, making this report 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. Increased suspension stability towards polar solvents for the nanotubes with high concentrations of MnO2 deposits, and in non-polar solvents the nanotubes with large alkyl chains attached was observed, thus proving it to be a versatile treatment.