PURIFICATION OF SINGLE-WALL CARBON NANOTUBES BY MICROFILTRATION

A purification procedure for single-wall carbon nanotubes (SWNTs) prep ared by pulsed laser ablation is discussed, which separates coexisting carbon nanospheres (CNS), metal nanoparticles, polyaromatic carbons, and fullerenes from the SWNT fraction, The process involves the suspen sion of CNS, metal nanoparticles, and SWNTs in an aqueous solution usi ng a cationic surfactant and the subsequent trapping of SWNTs on a mem brane filter, No oxidative treatment is required. Scanning/transmissio n electron microscopy and Raman scattering were used to evaluate the p urification process and the vibrational features of SWNTs. Purity of S WNTs at the final stage sample is in excess of 90% by weight, and no e vidence of impurity carbon phases was revealed in the Raman spectrum o f the SWNT fraction.