Monitoring oxidation of multiwalled carbon nanotubes by Raman spectroscopy

Authors

  • Sebastian Osswald,

    1. Department of Materials Science and Engineering, and A.J. Drexel Nanotechnology Institute, Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104, USA
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  • Mickael Havel,

    1. Department of Materials Science and Engineering, and A.J. Drexel Nanotechnology Institute, Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104, USA
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  • Yury Gogotsi

    Corresponding author
    1. Department of Materials Science and Engineering, and A.J. Drexel Nanotechnology Institute, Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104, USA
    • Department of Materials Science and Engineering, and A.J. Drexel Nanotechnology Institute, Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104, USA.
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Abstract

Multiwalled carbon nanotubes (MWCNTs) were oxidized in air and acids while varying the treatment time and/or temperature. The goal of this approach was to create the highest density of carboxyl groups with moderate sample loss, which is necessary for nanocomposite applications. In situ Raman experiments allowed real-time observation of the structural changes in MWCNTs upon oxidation. The ratio of the Raman intensities of the D and G bands was used to estimate the concentration of defects. It was found that while an oxidation for 6 h in H2SO4/HNO3 provided the strongest effect, a ‘flash oxidation’ in air (15 min at 550 °C) also leads to an efficient functionalization in a cost-effective and environmentally friendly way. Transmission electron microscopy, Fourier-transform infrared (FTIR) spectroscopy, thermogravimetric analysis and electrophoretic mobility analysis were used to study the oxidized nanotubes. Copyright © 2007 John Wiley & Sons, Ltd.

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