898results about "Single-walled nanotubes" patented technology

Single-walled carbon nanotubes have been synthesized by the catalytic decomposition of both carbon monoxide and ethylene over a supported metal catalyst known to produce larger multi-walled nanotubes. Under certain conditions, there is no termination of nanotube growth, and production appears to be limited only by the diffusion of reactant gas through the product nanotube mat that covers the catalyst The present invention concerns a catalyst-substrate system which promotes the growth of nanotubes that are predominantly single-walled tubes in a specific size range, rather than the large irregular-sized multi-walled carbon fibrils that are known to grow from supported catalysts. With development of the supported catalyst system to provide an effective means for production of single-wall nanotubes, and further development of the catalyst geometry to overcome the diffusion limitation, the present invention will allow bulk catalytic production of predominantly single-wall carbon nanotubes from metal catalysts located on a catalyst supporting surface.

Disclosed are copolymers of carbon nanotubes, as well as processes and applications of carbon nanotube dispersions. Carbon nanotube emulsions and related technology are also disclosed. The controlled deposition of carbon nanotubes on substrates is also provided. Methods of purifying single-walled carbon nanotubes are also provided. Devices made according to the disclosed methods are further described herein.

This invention is directed to making chemical derivatives of carbon nanotubes and to uses for the derivatized nanotubes, including making arrays as a basis for synthesis of carbon fibers. In one embodiment, this invention also provides a method for preparing single wall carbon nanotubes having substituents attached to the side wall of the nanotube by reacting single wall carbon nanotubes with fluorine gas and recovering fluorine derivatized carbon nanotubes, then reacting fluorine derivatized carbon nanotubes with a nucleophile. Some of the fluorine substituents are replaced by nucleophilic substitution. If desired, the remaining fluorine can be completely or partially eliminated to produce single wall carbon nanotubes having substituents attached to the side wall of the nanotube. The substituents will, of course, be dependent on the nucleophile, and preferred nucleophiles include alkyl lithium species such as methyl lithium. Alternatively, fluorine may be fully or partially removed from fluorine derivatized carbon nanotubes by reacting the fluorine derivatized carbon nanotubes with various amounts of hydrazine, substituted hydrazine or alkyl amine. The present invention also provides seed materials for growth of single wall carbon nanotubes comprising a plurality of single wall carbon nanotubes or short tubular molecules having a catalyst precursor moiety covalently bound or physisorbed on the outer surface of the sidewall to provide the optimum metal cluster size under conditions that result in migration of the metal moiety to the tube end.

A method for growing single-wall carbon nanotubes involves preparing a catalyst comprising catalytic metals, iron and molybdenum, and magnesium oxide support material and contacting the catalyst with a gaseous carbon-containing feedstock at a sufficient temperature and for a sufficient contact time to make single-wall carbon nanotubes. The weight ratio of iron and molybdenum can range from about 2 to 1 to about 10 to 1 and the metals loading up to about 10 wt % of the MgO. The catalyst can be sulfided. Methane is a suitable carbon-containing feedstock. The process can be conducted in batch, continuous or semi-continuous modes, in reactors, such as a transport reactor, fluidized bed reactor, moving bed reactors and combinations thereof. The process also includes making single-wall carbon nanotubes with catalysts comprising at least one Group VIB or Group VIIIB metal on supports such as magnesia, zirconia, silica, and alumina, where the catalyst is sulfided.