Solvent-free derivatization of oxidized single-walled carbon nanotubes and nanodiamond with aminobenzo-crown ethers

ABSTRACT

We report on a one-step amide derivatization of two carbon nanomaterials (CNM) containing carboxylic functional groups, which are oxidized single-walled carbon nanotubes (SWNTs) and nanodiamond (ND), with amino-substituted crown ethers, namely, 4′-aminobenzo-15-crown-5 and 4′-aminobenzo-18-crown-6. The functionalization procedure proposed is based on thermal activation of COOH groups instead of traditional chemical activation, is fast and facile, does not require the use of organic solvents and can be considered as ecologically friendly. The nanohybrids of crown ethers with SWNTs and ND were characterized by means of Fourier-transform infrared and Raman spectroscopy, scanning and transmission electron microscopy, as well as thermogravimetric analysis and solubility tests in toluene and propanol. The approach proposed allows for a facile preparation of crown ether-functionalized SWNTs and ND without contamination with other chemical reagents, solvents and detergents, which might be especially important for a broad spectrum of applications ranging from nanoelectronics to nanomedicine.

KEYWORDS:

• Single-walled carbon nanotubes
• Nanodiamond
• Functionalization
• Solvent-free
• Aminobenzo-crown ethers
• Amidation

Acknowledgments

Financial support from the National Autonomous University of Mexico (UNAM; grant DGAPA-IN200516) is greatly appreciated. The authors thank Fis. Roberto Hernández for technical assistance with TEM imaging.