720results about "Carbonsing rags" patented technology

A method of fabricating a long carbon nanotube yarn includes the following steps: (1) providing a flat and smooth substrate; (2) depositing a catalyst on the substrate; (3) positioning the substrate with the catalyst in a furnace; (4) heating the furnace to a predetermined temperature; (5) supplying a mixture of carbon containing gas and protecting gas into the furnace; (6) controlling a difference between the local temperature of the catalyst and the furnace temperature to be at least 50° C.; (7) controlling the partial pressure of the carbon containing gas to be less than 0.2; (8) growing a number of carbon nanotubes on the substrate such that a carbon nanotube array is formed on the substrate; and (9) drawing out a bundle of carbon nanotubes from the carbon nanotube array such that a carbon nanotube yarn is formed.

A method of self-cleaning a plasma reactor upon depositing a carbon-based film on a substrate a pre-selected number of times, includes: (i) exciting oxygen gas and / or nitrogen oxide gas to generate a plasma; and (ii) exposing to the plasma a carbon-based film accumulated on an upper electrode provided in the reactor and a carbon-based film accumulated on an inner wall of the reactor.

A method of forming a periodic array of nano-scale objects using a block copolymer, and nano-scale object arrays formed from the method are provided. The method for forming the arrays generally includes the steps of depositing a block copolymer of at least two blocks on a substrate to form an ordered meso-scale structured array of the polymer materials, forming catalytic metal dots based on the meso-scale structure, and growing nano-scale objects on the catalytic dots to form an ordered array of nano-scale objects.

A novel method of forming catalyst particles, on which carbon nanotubes grow based, on a substrate with increased uniformity, and a method of synthesizing carbon nanotubes having improved uniformity are provided. A catalytic metal precursor solution is applied to a substrate. The applied catalytic metal precursor solution is freeze-dried, and then reduced to catalytic metal. The method of forming catalyst particles can minimize agglomeration and / or recrystallization of catalyst particles when forming the catalyst particles by freeze-drying the catalyst metal precursor solution. The catalyst particles formed by the method has a very uniform particle size and are very uniformly distributed on the substrate.

An economical method of preparing a large-sized graphene sheet having a desired thickness includes forming a film, the film comprising a graphitizing catalyst; heat-treating a gaseous carbon source in the presence of the graphitizing catalyst to form graphene; and cooling the graphene to form a graphene sheet. A graphene sheet prepared according to the disclosed method is also described.

This invention relates to rigid porous carbon structures and to methods of making same. The rigid porous structures have a high surface area which are substantially free of micropores. Methods for improving the rigidity of the carbon structures include causing the nanofibers to form bonds or become glued with other nanofibers at the fiber intersections. The bonding can be induced by chemical modification of the surface of the nanofibers to promote bonding, by adding "gluing" agents and / or by pyrolyzing the nanofibers to cause fusion or bonding at the interconnect points.

A process for producing hollow, single-walled carbon nanotubes by catalytic decomposition of one or more gaseous carbon compounds by first forming a gas phase mixture carbon feed stock gas comprising one or more gaseous carbon compounds, each having one to six carbon atoms and only H, O, N, S or Cl as hetero atoms, optionally admixed with hydrogen, and a gas phase metal containing compound which is unstable under reaction conditions for said decomposition, and which forms a metal containing catalyst which acts as a decomposition catalyst under reaction conditions; and then conducting said decomposition reaction under decomposition reaction conditions, thereby producing said nanotubes.

A carbon nanotube yarn includes a number of carbon nanotube yarn strings bound together, and each of the carbon nanotube yarn strings includes a number of carbon nanotube bundles that are joined end to end by van der Waals attractive force, and each of the carbon nanotube bundles includes a number of carbon nanotubes substantially parallel to each other. A method for making the carbon nanotube yarn includes soaking the at least one carbon nanotube yarn string drawn out from a carbon nanotube array in an organic solvent to shrink it and then collecting it.

Carbon nanotubes are grown directly on metal substrates using chemical vapor deposition. Metal substrates are comprised of catalysts which facilitate or promote the growth of carbon nanotubes. The nanotube coated metal substrates have applications including, but not limited to, heat transfer and thermal control, hydrogen storage, fuel cell catalytic reformers, electronics and semiconductors, implantable medical devices or prostheses, and tribological wear and protective coatings.

Novel methods and apparati for continuous production of aligned carbon nanotubes are disclosed. In one aspect, the method comprises dispersion of a metal catalyst in a liquid hydrocarbon to form a feed solution, and volatilizing the feed solution in a reactor through which a substrate is continuously passed to allow growth of nanotubes thereon. In another aspect, the apparatus comprises a reactor, a tube-within-a-tube injector, and a conveyor belt for passing a substrate through the reactor. The present invention further discloses a method for restricting the external diameter of carbon nanotubes produced thereby comprising passing the feed solution through injector tubing of a specified diameter, followed by passing the feed solution through an inert, porous medium. The method and apparati of this invention provide a means for producing aligned carbon nanotubes of a particular external diameter which is suitable for large scale production in an industrial setting.

Method and system for producing a selected pattern or array of at least one of a single wall nanotube and / or a multi-wall nanotube containing primarily carbon. A substrate is coated with a first layer (optional) of a first selected metal (e.g., Al and / or Ir) and with a second layer of a catalyst (e.g., Fe, Co, Ni and / or Mo), having selected first and second layer thicknesses provided by ion sputtering, arc discharge, laser ablation, evaporation or CVD. The first layer and / or the second layer may be formed in a desired non-uniform pattern, using a mask with suitable aperture(s), to promote growth of carbon nanotubes in a corresponding pattern. A selected heated feed gas (primarily CH4 or C2Hn with n=2 and / or 4) is passed over the coated substrate and forms primarily single wall nanotubes or multiple wall nanotubes, depending upon the selected feed gas and its temperature. Nanofibers, as well as single wall and multi-wall nanotubes, are produced using plasma-aided growth from the second (catalyst) layer. An overcoating of a selected metal or alloy can be deposited, over the second layer, to provide a coating for the carbon nanotubes grown in this manner.

A carbon nanotube yarn includes a number of carbon nanotube yarn strings bound together, and each of the carbon nanotube yarn strings includes a number of carbon nanotube bundles that are joined end to end by van der Waals attractive force, and each of the carbon nanotube bundles includes a number of carbon nanotubes substantially parallel to each other. A method for making the carbon nanotube yarn includes soaking the at least one carbon nanotube yarn string drawn out from a carbon nanotube array in an organic solvent to shrink it and then collecting it.

The present invention relates to a method for making a carbon nanotube film. The method includes the steps of: (a) forming an array of carbon nanotubes on a substrate; and (b) press the array of carbon nanotubes using a compressing apparatus, thereby forming a carbon nanotube film.

A carbon nano-fiber, particularly twisted carbon nano-fiber such as a carbon nano-coil, carbon nano-twist, carbon nano-rope is produced by means of a catalyst CVD method using carbon-containing gas as a raw material and a catalyst comprising one or plural components selected from the group consisting of Cr, Mn, Fe, Co, Ni and oxide thereof and one or plural components selected from the group consisting of Cu, Al, Si, Ti, V, Nb, Mo, Hf, Ta, W and oxide thereof is used.

Disclosed is a method of exfoliating a layered material (e.g., graphite and graphite oxide) to produce nano-scaled platelets having a thickness smaller than 100 nm, typically smaller than 10 nm, and often between 0.34 nm and 1.02 nm. The method comprises: (a) subjecting the layered material in a powder form to a halogen vapor at a first temperature above the melting point or sublimation point of the halogen at a sufficient vapor pressure and for a duration of time sufficient to cause the halogen molecules to penetrate an interlayer space of the layered material, forming a stable halogen-intercalated compound; and (b) heating the halogen-intercalated compound at a second temperature above the boiling point of the halogen, allowing halogen atoms or molecules residing in the interlayer space to exfoliate the layered material to produce the platelets. Alternatively, rather than heating, step (a) is followed by a step of dispersing the halogen-intercalated compound in a liquid medium which is subjected to ultrasonication for exfoliating the halogen-intercalated compound to produce the platelets, which are dispersed in the liquid medium. The halogen can be readily captured and re-used, thereby significantly reducing the impact of halogen to the environment. The method can further include a step of dispersing the platelets in a polymer or monomer solution or suspension as a precursor step to nanocomposite fabrication.

A method for directly growing carbon nanotubes, and in particular single-walled carbon nanotubes on a flat substrate, such as a silicon wafer, and subsequently transferring the nanotubes onto the surface of a polymer film, or separately harvesting the carbon nanotubes from the flat substrate.

A process for production of an agglomerate comprises the steps of: passing a flow of one or more gaseous reactants into a reactor; reacting the one or more gaseous reactants within a reaction zone of the reactor to form product particles; agglomerating the product particles into an agglomerate; and applying a force to the agglomerate to displace it continuously away from the reaction zone.

The invention relates to a composite comprising a weight fraction of single-wall carbon nanotubes and at least one polar polymer wherein the composite has an electrical and / or thermal conductivity enhanced over that of the polymer alone. The invention also comprises a method for making this polymer composition. The present application provides composite compositions that, over a wide range of single-wall carbon nanotube loading, have electrical conductivities exceeding those known in the art by more than one order of magnitude. The electrical conductivity enhancement depends on the weight fraction (F) of the single-wall carbon nanotubes in the composite. The electrical conductivity of the composite of this invention is at least 5 Siemens per centimeter (S / cm) at (F) of 0.5 (i.e. where single-wall carbon nanotube loading weight represents half of the total composite weight), at least 1 S / cm at a F of 0.1, at least 1×10−4 S / cm at (F) of 0.004, at least 6×10−9 S / cm at (F) of 0.001 and at least 3×10−16 S / cm (F) plus the intrinsic conductivity of the polymer matrix material at of 0.0001. The thermal conductivity enhancement is in excess of 1 Watt / m-° K. The polar polymer can be polycarbonate, poly(acrylic acid), poly(acrylic acid), poly(methacrylic acid), polyoxide, polysulfide, polysulfone, polyamides, polyester, polyurethane, polyimide, poly(vinyl acetate), poly(vinyl alcohol), poly(vinyl chloride), poly(vinyl pyridine), poly(vinyl pyrrolidone), copolymers thereof and combinations thereof. The composite can further comprise a nonpolar polymer, such as, a polyolefin polymer, polyethylene, polypropylene, polybutene, polyisobutene, polyisoprene, polystyrene, copolymers thereof and combinations thereof.

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.

Catalytically activated carbon fibers and methods for their preparation are described. The activated carbon fibers are engineered to have a controlled porosity distribution that is readily optimized for specific applications using metal-containing nanoparticles as activation catalysts. The activated carbon fibers may be used in all manner of devices that contain carbon materials, including but not limited to various electrochemical devices (e.g., capacitors, batteries, fuel cells, and the like), hydrogen storage devices, filtration devices, catalytic substrates, and the like.

A gas-phase method for producing high yields of single-wall carbon nanotubes with high purity and homogeneity is disclosed. The method involves using preformed metal catalyst clusters to initiate and grow single-wall carbon nanotubes. In one embodiment, multi-metallic catalyst precursors are used to facilitate the metal catalyst cluster formation. The catalyst clusters are grown to the desired size before mixing with a carbon-containing feedstock at a temperature and pressure sufficient to initiate and form single-wall carbon nanotubes. The method also involves using small fullerenes and preformed sections of single-wall carbon nanotubes, either derivatized or underivatized, as seed molecules for expediting the growth and increasing the yield of single-wall carbon nanotubes. The multi-metallic catalyst precursors and the seed molecules may be introduced into the reactor by means of a supercritical fluid. In addition the seed molecules may be introduced into the reactor via an aerosol or smoke.

The present invention relates to controlled growth of carbon nanotube (CNT) arrays via chemical vapor deposition (CVD) using novel porous anodic aluminum oxide (AAO) templates, which have been seeded with transition metal catalysts. The resulting CNT bundles may be dense and long and can be used for numerous applications. Further, the porous AAO templates and the CNTs grown thereby, can be functionalized and used for separation of chemical species, hydrogen storage, fuel cell electrocatalyst and gas flow membranes, other catalytic applications, and as a bulk structural material.

Apparatus and method for electrospinning fibers in which the apparatus includes a spray head having a longitudinal axis and including at least one electrospinning element disposed in a peripheral wall of the spray head surrounding the longitudinal axis. The electrospinning element includes a passage by which a substance from which the fibers are to be electrospun is provided to a tip of the electrospinning element. The electrospinning element extends from the peripheral wall in a direction from the longitudinal axis and is configured to electrospin the fibers by electric field extraction of the substance from the tip of the electrospinning element. Accordingly, the method includes providing a substance from which the fibers are to be composed to a tip of an electrospinning element in a peripheral wall of a spray head having a longitudinal axis, rotating the spray head or a collector configured to receive the fibers around the longitudinal axis, applying in a direction from the longitudinal axis of the spray head an electric field to the tip of the electrospinning element to electrospin by electric field extraction the substance from the tip of the electrospinning element to form the fibers, and collecting the fibers on the collector.

A method for forming a carbon nanotube array using a metal substrate includes the following steps: providing a metal substrate (11); oxidizing the metal substrate to form an oxidized layer (21) thereon; depositing a catalyst layer (31) on the oxidized layer; introducing a carbon source gas; and thus forming a carbon nanotube array (61) extending from the metal substrate. Generally, any metallic material can be used as the metal substrate. Various carbon nanotube arrays formed using various metal substrates can be incorporated into a wide variety of high power electronic device applications such as field emission devices (FEDs), electron guns, and so on. Carbon nanotubes formed using any of a variety of metal substrates are well aligned, and uniformly extend in a direction substantially perpendicular to the metal substrate.

A method for making carbon nanotube particulates involves providing a catalyst comprising catalytic metals, such as iron and molybdenum or metals from Group VIB or Group VIIIB elements, on a support material, such as magnesia, and contacting the catalyst with a gaseous carbon-containing feedstock, such as methane, at a sufficient temperature and for a sufficient contact time to make small-diameter carbon nanotubes having one or more walls and outer wall diameters of less than about 3 nm. Removal of the support material from the carbon nanotubes yields particulates of enmeshed carbon nanotubes that retain an approximate three-dimensional shape and size of the particulate support that was removed. The carbon nanotube particulates can comprise ropes of carbon nanotubes. The carbon nanotube particulates disperse well in polymers and show high conductivity in polymers at low loadings. As electrical emitters, the carbon nanotube particulates exhibit very low “turn on” emission field.