The method for surface functionalization of single-walled carbon nanotubes with fuming nitric acid

✍ Scribed by Hiroshi Kitamura; Masaru Sekido; Hisato Takeuchi; Masatomi Ohno

• Publisher: Elsevier Science
• Year: 2011
• Tongue: English
• Weight: 590 KB
• Volume: 49
• Category: Article
• ISSN: 0008-6223
• DOI: 10.1016/j.carbon.2011.05.020

✦ Synopsis

Surface functionalization of single-walled carbon nanotubes (SWCNTs) was carried out using fuming nitric acid as a NO 2 radical source. The surface double bonds of the SWCNTs reacted with the NO 2 radicals at 10-90 °C under sonication, and following treatment with aqueous NaOH yielded modified carbon nanotubes with high affinity for polar solvents such as dimethylformamide. The structure of the product was characterized using Fourier transform-infrared spectroscopy (FT-IR), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis, and atomic force microscopy. FT-IR and XPS spectra revealed the product has OH groups (3400, 1200 cm À1 ), which was expected due to the addition of NO 2 radicals to the surface double bonds and subsequent substitution with OH groups. C 1s curve fitting analysis of the XPS spectra was used to quantitatively determine the different functional groups on the surface, and the amount of COOH groups was found to be increased from 2.8% to 9.3% due to progressive oxidation by increasing the reaction temperature from 10 to 90 °C.