Reduced damage to carbon nanotubes during ultrasound-assisted dispersion as a result of supercritical-fluid treatment

A pre-treatment method of carbon nanotubes for ultrasound-assisted dispersion in a solution is reported. Compared to untreated nanotubes, supercritical-fluid (SCF)-treated carbon nanotubes were easily dispersed in an aqueous surfactant solution by using ultrasonication. The nanotubes are found to be less damaged and less shortened, which was confirmed by Raman spectroscopy and dynamic light scattering, respectively. Supercritical ethane was more effective than supercritical CO2 in treating the carbon nanotubes.