Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Centrifugal Length Separation of Carbon Nanotubes



Jeffrey A. Fagan, Matthew Becker, Jae H. Chun, Barry J. Bauer, Jeffrey R. Simpson, Angela R. Hight Walker, Erik K. Hobbie


Separation of single wall carbon nanotubes (SWCNTs) by length via centrifugation in a high density medium, and the characterization of both the separated fractions and the centrifugation process are presented. Significant quantities of the separated SWCNTs ranging in average length from < 50 nm to  2 m were produced, with the distribution width being coupled to the rate of the separation. Less rapid separation is shown to produce narrower distributions; these length fractions, produced using sodium deoxycholate dispersed SWCNTs, were characterized by UV-Visible-near infrared absorption and fluorescence spectroscopy, dynamic light scattering, Raman scattering and atomic force microscopy. Several parameters of the separation were additionally explored: SWCNT concentration, added salt concentration, liquid density, rotor speed, surfactant concentration, and the processing temperature. The centrifugation technique is shown to support ten milligram per day scale processing and is applicable to all of the major SWCNT production methods: CoMoCat, HiPco, laser ablation, and electric arc. The cost per unit of the centrifugation based separation is also demonstrated to be significantly less than size exclusion chromatography based separations.


carbon nanotubes, SWCNT, SWNT, deoxycholate, length, centrifugation, separation


Fagan, J. , Becker, M. , Chun, J. , Bauer, B. , Simpson, J. , Hight, A. and Hobbie, E. (2008), Centrifugal Length Separation of Carbon Nanotubes, Langmuir, [online], (Accessed June 12, 2024)


If you have any questions about this publication or are having problems accessing it, please contact

Created October 1, 2008, Updated February 19, 2017