Abstract
Carbon nanotubes consist of one or more concentric graphene cylinders and are under investigation for a variety of applications that make use of their excellent thermal, mechanical, electronic and optical properties. Double-wall nanotubes are ideal systems for studying the interwall interactions influencing the properties of nanotubes with two or more walls. However, current techniques to synthesize double-wall nanotubes produce unwanted single- and multiwall nanotubes. Here, we show how density gradient ultracentrifugation can be used to separate double-wall nanotubes from mixtures of single- and multiwall nanotubes through differences in their buoyant density. This technique results in samples that are highly enriched in either single- or double-wall nanotubes of similar outer wall diameter, with the double-wall nanotubes being, on average, ∼44% longer than the single-wall nanotubes. The longer average length of the double-wall nanotubes provides distinct advantages when they are used in transparent conductors.
Original language | English (US) |
---|---|
Pages (from-to) | 64-70 |
Number of pages | 7 |
Journal | Nature nanotechnology |
Volume | 4 |
Issue number | 1 |
DOIs | |
State | Published - Jan 2009 |
Funding
The authors wish to acknowledge G. N. Ostojic for helpful discussions and S. Li for help with transmission electron microscopy. This work was supported by the US 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.G.) and an Alfred P. Sloan Research Fellowship (M.C.H.) are also acknowledged. We acknowledge the use of instruments in the Keck-II and EPIC facility of the NUANCE Center, and the Keck Biophysics Facility at Northwestern University. The NUANCE Center is supported by NSF-NSEC, NSF-MRSEC, the Keck Foundation, the State of Illinois and Northwestern University.
ASJC Scopus subject areas
- Condensed Matter Physics
- Bioengineering
- Atomic and Molecular Physics, and Optics
- General Materials Science
- Electrical and Electronic Engineering
- Biomedical Engineering