Dispersion of Pristine Multi-Walled Carbon Nanotubes in Common Organic Solvents

The dispersion of pristine multi-walled carbon nanotubes in various common organic solvents and water has been investigated. Sedimentation tests, optical microscopy, transmission electron microscopy and Tyndall effect tests are employed. The results clearly show that N-methyl-2-pyrrolodone, acetone, tetrahydrofuran and dichloromethane are good solvents to debundle and disperse the multi-walled carbon nanotubes. In contrast, much precipitation can be obviously observed for systems of the carbon nanotubes in water, ethanol and toluene. Additionally, Tyndall effect tests suggest that the upper dispersions of the carbon nanotubes in acetone, tetrahydrofuran and dichloromethane with a concentration of 0.1 mg/mL and the dispersion of carbon nanotubes in N-methyl-2-pyrrolodone with a concentration of 0.05 mg/mL are colloidal systems rather than solutions. Finally, based on the above results, a possible mechanism is briefly discussed.