Research Article

Nano Research

, Volume 2, Issue 1, pp 69-77

Open Access This content is freely available online to anyone, anywhere at any time.

Isolation of single-walled carbon nanotube enantiomers by density differentiation

  • Alexander A. GreenAffiliated withDepartment of Materials Science and Engineering and Department of Chemistry, Northwestern University
  • , Matthew C. DuchAffiliated withDepartment of Materials Science and Engineering and Department of Chemistry, Northwestern University
  • , Mark C. HersamAffiliated withDepartment of Materials Science and Engineering and Department of Chemistry, Northwestern University Email author 

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.

http://static-content.springer.com/image/art%3A10.1007%2Fs12274-009-9006-y/MediaObjects/12274_2009_9006_Fig1_HTML.jpg

Keywords

Carbon nanotube separation handedness enantiomer optical activity chirality