Sidewall Covalent Functionalization of Single Wall Carbon Nanotubes through C-N Bond Forming Reactions of Fluoronanotubes with Urea, Guanidine and Thiourea (Preprint)

摘要

Sidewall covalent functionalization of carbon nanotubes is necessary to achieve smaller bundles, link to other functional moieties, and to aid in better dispersion in composites. In the present study, we present a one-step functionalization method which uses fluorinated single wall carbon nanotubes (F- SWNTs) as starting materials in the reactions with either urea, thiourea, or guanidine. Through these reactions, the derivatives with terminal amide and heteroamide groups on the nanotube sidewalls have been prepared. The products still contain some residual fluorine creating bifunctional nanotubes. These derivatives were characterized by Raman spectroscopy, Fourier transform infrared (FTIR), thermo gravimetric analysis (TGA), scanning electron microscopy (SEM), x-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and atomic force microscopy (AFM). Compared to fluorinated tubes, the urea-F-SWNTs, among the three derivatives, have shown the highest stability in water and aqueous urea solutions, thereby creating new opportunities for biomedical applications with nanotubes. These bifunctional derivatives will aid in creating an interface between the SWNTs and polymers, which will result in much stronger composites. The three derivatives are easily and rapidly synthesized, and the method can be easily scaled up for applications such as creating an integrated polymer network for stronger composites, coatings, for use in biomedical applications and nanoelectronic devices.