Single-chirality separation of ultra-thin semiconducting arc discharge single-walled carbon nanotubes

Ultra-thin single-walled carbon nanotubes (SWCNTs) with a narrow diameter distribution are prepared with a Fe catalyst under an optimized H₂/He atmosphere by arc discharge first time. These SWCNTs were enriched with a pH–temperature controlled gel chromatography single-chirality separation process. The separation process uses the electrostatic interaction between the gel and the functional groups on the sidewalls of nanotubes, which is defined by the curvature of the C–C bond and the chiral vector (n, m). Tuning the interaction through varying the pH and temperature enables the separation of five species from the sodium dodecyl sulfate (SDS) wrapped SWCNTs in aqueous solution, namely (7, 5), (9, 4), (7, 6), (8, 6), and (8, 7), as evidenced by several optical spectroscopy techniques.