Submilligram-scale separation of near-zigzag single-chirality carbon nanotubes by temperature controlling a binary surfactant system

Mass production of zigzag and near-zigzag single-wall carbon nanotubes (SWCNTs), whether by growth or separation, remains a challenge, which hinders the disclosure of their previously unknown property and practical applications. Here, we report a method to separate SWCNTs by chiral angle through temperature control of a binary surfactant system of sodium cholate (SC) and SDS in gel chromatography. Eleven types of single-chirality SWCNT species with chiral angle less than 20° were efficiently separated including multiple zigzag and near-zigzag species. Among them, (7, 3), (8, 3), (8, 4), (9, 1), (9, 2), (10, 2), and (11, 1), were produced on the submilligram scale. The spectral detection results indicate that lowering the temperature induced selective adsorption and reorganization of the SC/SDS cosurfactants on SWCNTs with different chiral angles, amplifying their interaction difference with gel. We believe that this work is an important step toward industrial separation of single-chirality zigzag and near-zigzag SWCNTs.