Small-angle neutron scattering from labeled single-wall carbon nanotubes

Small-angle neutron scattering (SANS) is used with the "high- concentration" method to extract single-particle scattering from single-wall carbon nanotubes (SWNTs). The SWNT material was labeled by covalently attaching - C 4H 9 or - C 4D 9 groups by use of free radical chemistry. Mixtures of SWNT-C 4H 9 and SWNT-C 4D 9 were dispersed in D 2O containing 1% sodium lauryl sulfate-d 23 (SLS) by use of sonication. SLS matches the neutron contrast of D 2O so that all of the SANS is due to the labeled SWNT. Thermogravimetric analysis shows that mass fractions of butyl groups attached to the SWNT-C 4H 9 and the SWNT-C 4D 9 were well matched. The scattering had a power law of - 2.5, which is characteristic of a "particle" made of clustered SWNTs. The clustering seen in SWNT scattering is due to collections of SWNTs that do not exchange in a dynamic equilibrium with other nanotubes.

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Author Matthew L Becker Chemistry