You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither SPIE nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the SPIE website.
4 September 2008Light-induced accumulation of single-wall carbon nanotubes dispersed in aqueous solution
We present evidence that, when laser light was tightly focused into aqueous suspension of
mono-dispersed single-wall carbon nanotubes (SWCNTs), density of nanotubes was locally
increased at the focus spot of light. We prepared mono-dispersed HiPco SWCNTs in an aqueous
surfactant solution by sonication and following ultracentrifugation. We built a confocal Raman
microscope system equipped with a 633 nm He-Ne laser, and launched the laser light into SWCNTs
suspension filled in a glass micro-cell by a high numerical aperture objective lens (N.A.=1.35).
We monitored temporal change in Raman spectrum of SWCNTs excited by the laser light. We
clearly observed significant intensity increase of a particular radial breathing mode, however the
increase of the Raman signal did not last permanently, rather showed transient response. This
result implies that SWCNTs with particular chirality were selectively accumulated by optical
gradient force of Raman-probing laser light. We discuss the independent behavior of the radial
breathing modes, with respect to the wavelength of the laser light and the chirality of corresponding
SWCNTs.