Abstract
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 refined samples enables identification of high-energy optical transitions in SWNTs.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 69-77 |
| Number of pages | 9 |
| Journal | Nano Research |
| Volume | 2 |
| Issue number | 1 |
| DOIs | |
| State | Published - Jan 2009 |
Funding
The authors thank M. S. Arnold for helpful discussions and preliminary measurements. This work was supported by the U.S. Army Telemedicine and Advanced Technology Research Center (DAMD17-05-1-0381) and the National Science Foundation (DMR-0520513, EEC-0647560, and DMR-0706067). A Natural Sciences and Engineering Research Council of Canada Postgraduate Scholarship (A. A. Green) and an Alfred P. Sloan Research Fellowship (M. C. Hersam) are also acknowledged. This work made use of instruments in the Keck-II facility of the NUANCE Center and the Keck Biophysics Facility at Northwestern University. The NUANCE Center is supported by NSF-NSEC, NSF-MRSEC, Keck Foundation, the State of Illinois, and Northwestern University.
Keywords
- Carbon nanotube
- Chirality
- Enantiomer
- Handedness
- Optical activity
- Separation
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics
- General Materials Science
- Condensed Matter Physics
- Electrical and Electronic Engineering