Isolation of single-walled carbon nanotube enantiomers by density differentiation
Carbon nanotube, separation, handedness, enantiomer, optical activity, chirality
Current methods of synthesizing single-walled carbon nanotubes (SWNTs) result in racemic mixtures that have impeded the study of left- and right-handed SWNTs. Here we present a method of isolating different SWNT enantiomers using density gradient ultracentrifugation. Enantiomer separation is enabled by the chiral surfactant sodium cholate, which discriminates between left- and right-handed SWNTs and thus induces subtle differences in their buoyant densities. This sorting strategy can be employed for simultaneous enrichment by handedness and roll-up vector of SWNTs having diameters ranging from 0.7 to 1.5 nm. In addition, circular dichroism of enantiomer re? ned samples enables identi? cation of high-energy optical transitions in SWNTs.
Tsinghua University Press
Alexander A. Green, Matthew C. Duch, Mark C. Hersam. Isolation of single-walled carbon nanotube enantiomers by density differentiation. Nano Res.2009, 2: 69-77.