Solvation of Fluorinated Single-Wall Carbon Nanotubes in Alcohol Solvents

Abstract

Highly purified single-wall carbon nanotubes (SWNTs) were fluorinated to form "fluorotubes", which were then solvated as individual tubes in various alcohol solvents via ultrasonication. The solvation of individual fluorotubes was verified by dispersing the tubes on a mica substrate and examining them with atomic force microscopy (AFM). Elemental analysis of the tubes reveals that light sonication in alcohol solvents does not remove significant amounts of the fluorine. While these solutions are metastable, they will persist long enough (over a week) to permit solution-phase chemistry to be carried out on the fluorotubes. For example, the solvated fluorotubes can be precipitated out of solution with hydrazine to yield normal, unfluorinated SWNTs, or they can be reacted with sodium methoxide to yield what are apparently methoxylated SWNTs. These reaction products have been examined with elemental analysis and a variety of spectroscopies and microscopies.

Chemistry of Single-Walled Carbon Nanotubes

“…Nevertheless, a primary goal of our work was the preservation of the essential aspects of the carbon nanotube electronic structure. 6,7 The alternative method (Scheme 5) to functionalization makes use of side wall chemistry [93][94][95][96][97] with concomitant loss of the carbon nanotube conjugated electronic structure in order to render the SWNTs soluble. [95][96][97] The dissolution methods discussed above make use of ionic or covalent functionalization of the carbon nanotubes.…”

“…6,7 The alternative method (Scheme 5) to functionalization makes use of side wall chemistry [93][94][95][96][97] with concomitant loss of the carbon nanotube conjugated electronic structure in order to render the SWNTs soluble. [95][96][97] The dissolution methods discussed above make use of ionic or covalent functionalization of the carbon nanotubes. Noncovalent functionalization has also been shown to be effective in the dissolution of the carbon nanotubes, 98,99 together with polymer wrapping procedures.…”

“…7 Characterization of the functionalized species is a major difficulty in carbon nanotube chemistry, but in the case of wall chemistry, where the band electronic structure is disrupted, solution spectroscopy is a powerful tool; Raman spectroscopy has also been used to study the effects of sidewall functionalization. [93][94][95]109 Dichlorocarbene is an electrophilic reagent that will add to deactivated double bonds (Scheme 5) [103][104][105] and to fullerenes. 106,107 Electronic spectroscopy showed that the band-gap transitions in the semiconducting tubes were completely disrupted at a functionalization level of 2% of the available SWNT carbon atoms.…”

Funcionalização de nanotubos de Carbono

“…Também tem sido intensamente investigada, tanto teórica como experimentalmente, a fun-cionalização de nanotubos de carbono através de suas paredes com a adsorção de átomos ou moléculas [31][32][33][34][35][36][37][38] , através de dopagens substitucionais dos tubos [39][40][41] , por meio de deformações estruturais 42,43 ou ainda por adsorção de grupos químicos, como o COOH [44][45][46] . Na maioria destes casos, as propriedades eletrônicas e, conseqüentemente, a reatividade química são alteradas em função da funcionalização.…”

Carbon Nanotube‐based Vectors for Delivering Immunotherapeutics and Drugs

“…The investigation of absorption and Raman spectra indicated the electronic perturbation of fluorinated SWNTs. The fluorination allowed exfoliation of SWNTs bundles into individual nanotubes and remarkably improved the solubility of SWNTs in tetrahydrofuran (THF), dimethylformamide (DMF) and various alcohols [125]. The CaF bonds were very sensitive to the treatment with hydrazine, which allowed almost complete recovery of the conductivity and the spectroscopic properties of the pristine SWNTs [124].…”