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

A facile route to water-soluble graphite nanoplatelets that uses graphite as the starting material is described. The method relies on the addition of phenyl radicals with subsequent sulfonation of the phenyl groups. Atomic force microscopy, high-resolution transmission electron microscopy, and scanning tunneling microscopy images show that a high degree of exfoliation occurs during the sulfonation step. The sheet resistance of the bulk films of the nanoplatelets prepared by vacuum filtration using an anodisc membrane was found to be 212 Ω/sq.

Reduction of anthracite by electron transfer from either lithium or sodium in liquid ammonia yields a salt that can be alkylated by 1-iodododecane to yield nanocoal that is partially soluble in common organic solvents. NMR indicates that the dodecyl groups are attached to the edges of the aromatic ring systems, with many of the dodecyl groups extending into void spaces. Thermal gravimetric analysis shows that sodium gives a slightly higher level of functionalization. Atomic force microscopy (AFM) images of soluble dodecylated anthracite reveal nanoparticles that vary from 3 to 12 nm high. Scanning electron microscopy (SEM) and bright field high-resolution transmission electron microscopy (HRTEM) of the raw anthracite reveal a layered structure with dislocations. Inorganic materials that occur in the raw anthracite were identified by energy dispersive X-ray spectroscopy (EDS). Simple alkenes were found to react with the coal salt to give oligomers of the alkene that are grafted onto the surface of the coal.

In surfactant flooding for enhanced oil recovery, adsorption of surfactants on the porous media of an oil reservoir is a major concern. It weakens the efficacy of the injected surfactant in reducing oil–water interfacial tension (IFT) and makes the oil recovery process uneconomical. Colloidal silica nanoparticles were found to adsorb at a lower rate than surfactant in porous media because of their charge density and high surface area. Silica nanoparticle surfaces with a negative surface charge are expected to adsorb onto the same active sites in the reservoir as anionic surfactant molecules used in enhanced oil recovery (EOR) applications. Experiments conducted in sandpack demonstrated that pre-treatment of the sandpack with silica nanoparticles at 80°C reduced surfactant adsorption by a factor of three when using artificial seawater as the injection fluid.

In the interest of developing a highly sensitive, low power radiation dosimeter, a series of tests were performed on single-wall carbon nanotube (SWCNT)-based nanomaterials to monitor their response to 10 and 30 MeV proton radiation. The SWCNT materials were deposited on an interdigitated electrode (IDE) that was developed at NASA Ames for chemical sensing. In order to investigate the effects of nanotube functionalization on the sensor properties, the SWCNTs were covalently or noncovalently functionalized prior to their incorporation into the devices. The functionalized nanotubes which were assayed included fluorinated SWCNT (F-SWCNT), alkylated F-SWCNT (F-SWCNT-C 11 H 23 ), refluorinated alkylated F-SWCNT (F-SWCNT-C 11 F 23 ), palladium doped SWCNTs (Pd-SWCNTs), and nanotubes noncovalently associated with cellulose (Cel-SWCNTs). These five functionalized nanotube types and pristine carbon nanotubes were investigated for their responses to proton radiation. The device response to irradiation, measured as a change in resistance, was found to vary with the type of functional group attached to the SWCNT. The samples were also characterized by Raman spectroscopy in order to observe changes in the disorder band (at 1350 cm -1 ) of the nanotube materials. Depending on nanotube functionalization, the devices showed a real-time response to radiation at the energy levels tested. The nature of the response indicates that these nanomaterials may potentially be used to produce a dosimeter that is memory-free, reusable, and reversible.