707results about "Multi-walled nanotubes" patented technology

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 C₂H_n 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 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.

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.

The present invention relates to covalently bonded fullerene-functionalized carbon nanotubes (CBFFCNTs), a method and an apparatus for their production and to their end products. CBFFCNTs are carbon nanotubes with one or more fullerenes or fullerene based molecules covalently bonded to the nanotube surface. They are obtained by bringing one or more catalyst particles, carbon sources and reagents together in a reactor.

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.

A composite structure includes a matrix material and a carbon nanotube (CNT)-infused fiber material that includes a plurality of carbon nanotubes (CNTs) infused to a fiber material. The CNT-infused fiber material is disposed throughout a portion of the matrix material. The composite structure is adapted for application of a current through the CNT-infused fiber material to provide heating of the composite structure. A heating element includes a CNT-infused fiber material includes a plurality of CNTs infused to a fiber material. The CNT-infused fiber material is of sufficient proportions to provide heating to a structure in need thereof.

Continuous process for the production of carbon-based nanotubes, nanofibres and nanostructures, comprising the following steps: generating a plasma with electrical energy, introducing a carbon precursor and/or one or more catalysers and/or carrier plasma gas in a reaction zone of an airtight high temperature resistant vessel optionally having a thermal insulation lining, vaporizing the carbon precursor in the reaction zone at a very high temperature, preferably 4000° C. and higher, guiding the carrier plasma gas, the carbon precursor vaporized and the catalyser through a nozzle, whose diameter is narrowing in the direction of the plasma gas flow, guiding the carrier plasma gas, the carbon precursor vaporized and the catalyses into a quenching zone for nucleation, growing and quenching operating with flow conditions generated by aerodynamic and electromagnetic forces, so that no significant recirculation of feedstocks or products from the quenching zone into the reaction zone occurs, controlling the gas temperature in the quenching zone between about 4000° C. in the upper part of this zone and about 50° C. in the lower part of this zone and controlling the quenching velocity between 103 K/s and 106 K/s quenching and extracting carbon-based nanotubes, nanofibres and other nanostructures from the quenching zone, separating carbon-based nanotubes, nanofibres and nanostructures from other reaction products.

A field emission device having bundles of aligned parallel carbon nanotubes on a substrate. The carbon nanotubes are oriented perpendicular to the substrate. The carbon nanotube bundles may be up to 300 microns tall, for example. The bundles of carbon nanotubes extend only from regions of the substrate patterned with a catalyst material. Preferably, the catalyst material is iron oxide. The substrate is preferably porous silicon, as this produces the highest quality, most well-aligned nanotubes. Smooth, nonporous silicon or quartz can also be used as the substrate. The method of the invention starts with forming a porous layer on a silicon substrate by electrochemical etching. Then, a thin layer of iron is deposited on the porous layer in patterned regions. The iron is then oxidized into iron oxide, and then the substrate is exposed to ethylene gas at elevated temperature. The iron oxide catalyzes the formation of bundles of aligned parallel carbon nanotubes which grow perpendicular to the substrate surface. The height of the nanotube bundles above the substrate is determined by the duration of the catalysis step. The nanotube bundles only grow from the patterned regions.

The disclosed is a transparent conductive film that includes a matrix and carbon fibrous structures added to the matrix, wherein the carbon fibrous structures comprise carbon fibers, each having an outside diameter of 15-100 nm, and wherein the carbon fibrous structures each comprise a granular part at which two or more carbon fibers are bound to each other, and wherein the granular part is concurrently produced in a growth process for the carbon fibers. When the transparent conductive film is formed at a thickness of 0.1-5 μm on a glass substrate, it shows a surface resistivity of not more than 1.0×10¹²Ω/□, and a total light transmittance of not less than 30%. A coating composition for the conductive transparent film is prepared by using a media mill equipped with beads having an average diameter of 0.05-1.5 mm to disperse the carbon fibrous structures into the liquid resinous composition.

Disclosed herein is a material for altering electromagnetic radiation incident on the material. The material disclosed herein comprises carbon nanotubes having a length (L) that meets the following formula (1):

L≧½λ  (1)

where λ is the wavelength of the electromagnetic radiation incident on the material. Also disclosed herein are methods of altering electromagnetic radiation, including mitigating, intensifying, or absorbing and re-transmitting electromagnetic radiation using the disclosed material.

The present invention is directed to methods of functionalizing carbon nanotubes (CNTs), particularly single-wall carbon nanotubes (SWNTs), with organosilane species, wherein such functionalization enables fabrication of advanced polymer composites. The present invention is also directed toward the functionalized CNTs, advanced CNT-polymer composites made with such functionalized CNTs, and methods of making such advanced CNT-polymer composites.

The present invention relates to coated fullerenes comprising a layer of at least one inorganic material covering at least a portion of at least one surface of a fullerene and methods for making. The present invention further relates to composites comprising the coated fullerenes of the present invention and further comprising polymers, ceramics and/or inorganic oxides. A coated fullerene interconnect device wherein at least two fullerenes are contacting each other to form a spontaneous interconnect is also disclosed as well as methods of making. In addition, dielectric films comprising the coated fullerenes of the present invention and methods of making are further disclosed.

This invention relates to a solid divided composition comprising grains whose mean size is greater than 25 μm and less than 2.5 mm, wherein each grain is provided with a solid porous core and a homogeneous continuous metal layer consisting of at least one type of transition non-oxidised metal and extending along a gangue coating the core in such a way that pores are inaccessible. A method for the production of said composition and for the use thereof in the form of a solid catalyst is also disclosed.

The invention relates to derivatized, well-dispersed CNTs that have enhanced miscibility with organic agents. Composite materials may be made using such CNTs. The composite materials, in turn, may be used in optical and electronic applications.

This invention is directed to a method of patterning carbon nanotubes transparent electrically conductive coating/films, by modification of the applied carbon nanotube (CNT) network through use of sidewall group functionalization to disrupt electrical conductivity of the nanotubes. The resulting areas which undergo chemical modification are rendered more or less conductive than those areas which where not altered. This results in a patterned film, wherein said pattern is shaped to form electrodes, pixels, wires, antenna or other electrical component. In addition, the areas of chemically modified CNT can be returned to their original conductive state (i.e. reversible and repeatable), or fixed to yield a permanent pattern.

The present invention is generally directed to methods of functionalizing carbon nanotubes (CNTs) in acidic media. By first dispersing CNTs in an acidic medium, bundled CNTs can be separated as individual CNTs, affording exposure of the CNT sidewalls, and thereby facilitating the functionalization of such CNTs, wherein functional groups are attached to the subsequently exposed sidewalls of these individualized CNTs. Once dispersed in this substantially unhundled state, the CNTs are functionalized according to one or more of a variety of functionalization processes. Typically, ultrasonication or non-covalent wrapping is not needed to afford such dispersion and subsequent functionalization. Additionally, such methods are easily scalable and can provide for sidewall-functionalized CNTs in large, industrial-scale quantities.

A polymeric composition containing at least one polymer and carbon nanotubes is described. The polymeric composition can have carbon nanotubes that are multi-wall carbon nanotubes and/or single-wall carbon nanotubes. The compositions can also contain carbon black. Also described are various articles made from the polymeric compositions including cables and other articles.

A method is described for catalyst-induced growth of carbon nanotubes, nanofibers, and other nanostructures on the tips of nanowires, cantilevers, conductive micro/nanometer structures, wafers and the like. The method can be used for production of carbon nanotube-anchored cantilevers that can significantly improve the performance of scaning probe microscopy (AFM, EFM etc). The invention can also be used in many other processes of micro and/or nanofabrication with carbon nanotubes/fibers. Key elements of this invention include: (1) Proper selection of a metal catalyst and programmable pulsed electrolytic deposition of the desired specific catalyst precisely at the tip of a substrate, (2) Catalyst-induced growth of carbon nanotubes/fibers at the catalyst-deposited tips, (3) Control of carbon nanotube/fiber growth pattern by manipulation of tip shape and growth conditions, and (4) Automation for mass production.

This invention discloses high-efficiency method and apparatus for continuously producing carbon nanotubes. The apparatus is a multi-stage counter-current reaction apparatus. The method comprises: placing the catalyst in the pre-reactor or the main reactor, introducing mixed gases of H2 or CO, and N2 or Ar, reducing, then introducing raw material gas, reacting to obtain carbon nanotubes, and sending the expanded solid raw material to the next stage reactor for reaction. The gas flow and the solid raw material are arranged in counter-current contact mode in the reactors, which can increase the conversion rate of the solid raw material. This invention has such advantages as simple apparatus and easy operation, and is suitable for industrial production on the scale of tens of thousands of tons per year.