Selective enrichment of (6,5) and (8,3) single-walled carbon nanotubes via cosurfactant extraction from narrow (n,m) distribution samples.

Highly selective enrichment of (6,5) and (8,3) SWCNTs (above 85% of the semiconducting tubes) was achieved through multistep extraction by sodium dodecyl sulfate (SDS) and sodium cholate (SC) cosurfactant solution from narrowly (n,m) distributed SWCNTs produced by the catalyst Co-MCM-41. A systematic change in the chirality selectivity was observed when the weight ratio between SDS and SC varied in cosurfactant solutions, with maximum enrichment selectivity for (6,5) tubes yielded at 1:4. Furthermore, surfactants were washed away easily to produce "clean" SWCNTs. This observation sheds light on the possibility of obtaining SWCNTs with the desired (n,m) structure via an easily scalable approach. No selectivity was detected when using sodium dodecyl benzene sulfonate (SDBS)/SC cosurfactants, hence suggesting the need for further exploration of various cosurfactant combinations for more effective extraction of different (n,m) species.