Bench-Top Aqueous Two-Phase Extraction of Isolated Individual Single-Walled Carbon Nanotubes

Navaneetha K. Subbaiyan, A. Nicholas G. Parra-Vasquez, Sofie Cambré, Miguel A.Santiago Cordoba, Sibel Ebru Yalcin, Christopher E. Hamilton, Nathan H. Mack, Jeffrey L. Blackburn, Stephen K. Doorn, Juan G. Duque

Research output: Contribution to journalArticlepeer-review

40 Scopus Citations


Isolation and purification of single-walled carbon nanotubes (SWCNTs) are prerequisites for their implementation in various applications. In this work, we present a fast (∼5 min), low-cost, and easily scalable bench-top approach to the extraction of high-quality isolated SWCNTs from bundles and impurities in an aqueous dispersion. The extraction procedure, based on aqueous two-phase (ATP) separation, is widely applicable to any SWCNT source (tested on samples up to 1.7 nm in diameter) and independent of defect density, purity, diameter, and length. The extracted dispersions demonstrate that the removal of large aggregates, small bundles, and impurities is comparable to that by density gradient ultracentrifugation, but without the need for high-end instrumentation. Raman and fluorescence-excitation spectroscopy, single-nanotube fluorescence imaging, atomic force and transmission electron microscopy, and thermogravimetric analysis all confirm the high purity of the isolated SWCNTs. By predispersing the SWCNTs without sonication (only gentle stirring), full-length, pristine SWCNTs can be isolated (tested up to 20 μm). Hence, this simple ATP method will find immediate application in the generation of SWCNT materials for all levels of nanotube research and applications, from fundamental studies to high-performance devices.

Original languageAmerican English
Pages (from-to)1755-1769
Number of pages15
JournalNano Research
Issue number5
StatePublished - 2015

Bibliographical note

Publisher Copyright:
© 2014, Tsinghua University Press and Springer-Verlag Berlin Heidelberg.

NREL Publication Number

  • NREL/JA-5900-62300


  • aggregate removal
  • aqueous two-phase (ATP) separation
  • carbon nanotubes
  • isolation
  • sorting


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