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Open Access Research Article Issue
Radical Addition of Perfluorinated Alkyl Iodides to Multi-Layered Graphene and Single-Walled Carbon Nanotubes
Nano Research 2010, 3(2): 138-145
Published: 27 March 2010
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A simple one-pot reaction that serves to functionalize graphite nanosheets (graphene) and single-walled carbon nanotubes (SWNTs) with perfluorinated alkyl groups is reported. Free radical addition of 1-iodo-1H, 1H, 2H, 2H-perfluorododecane to ortho-dichlorobenzene suspensions of the carbon nanomaterial is initiated by thermal decomposition of benzoyl peroxide. Similarly, UV photolysis of 1-iodo-perfluorodecane serves to functionalize the carbon materials. Perfluorododecyl-SWNTs, perfluorododecyl-graphene, and perfluorodecyl-graphene are characterized by infrared (IR) and Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), and atomic force microscopy (AFM). The products show enhanced dispersability in CHCl3 as compared to unfunctionalized starting materials. The advantage of this one-pot functionalization procedure lies in the use of pristine graphite as starting material thereby avoiding the use of harsh oxidizing conditions.

Open Access Research Article Issue
Demonstration of Covalent Sidewall Functionalization of Single Wall Carbon Nanotubes by NMR Spectroscopy: Side Chain Length Dependence on the Observation of the Sidewall sp3 Carbons
Nano Research 2008, 1(1): 72-88
Published: 12 July 2008
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Carboxylic acid-functionalized single walled carbon nanotubes (SWNTs) prepared via the reaction of an amino acid, NH2(CH2)nCO2H where n = 1 (glycine, GLY), 5 (6-aminohexanoic acid, AHA), 10 (11-aminoundecanoic acid, AUDA), with fluorinated single walled carbon nanotubes (F-SWNTs) have been characterized by MAS 13C NMR spectroscopy. The ease of observing the aliphatic CH2 groups and the resolution of the signal are dependent on the length of the amino acid's aliphatic chain. We have proposed that where substituent chains are short (making NMR data collection difficult) chemical modification to extend the chain length should alleviate analysis problems. In this regard, we have investigated the esterification of the carboxylic acid termini. The amino acid-functionalized SWNTs were esterified with an appropriate alcohol to ensure parity of the overall substituent length, i.e., GLY-SWNT (C1) + 1-dodecanol (C12) = DOD-GLY-SWNT (1), AHA-SWNT (C5) + 1-octanol (C8) = OCT-AHA-SWNT (2), and AUDA-SWNT (C10) + 1-propanol (C3) = PRO-AUDA-SWNT (3). The 13C NMR shift for the sp3 nitrogen-substituted carbon atoms of the SWNT sidewall is observed at δ ≈ 75 ppm. Increasing the length of SWNT sidewall functional groups enhances the ability to observe the sidewall sp3 carbon. The methylene carbon signal intensity is less attenuated in the dipolar dephasing spectrum of the ester-functionalized SWNTs than their associated amino acid derivatives, suggesting more motional freedom of the side chain in the solid state. The confirmation of the dipolar dephasing spectral effects was assisted by the characterization of the ester of AUDA-SWNT with 1, 3-propanediol: PPD-AUDA-SWNT (4).

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