5000results about "Fibre chemical features" patented technology

This invention pertains to novel fibers made of α(1→;3) polysaccharides, and a process for their production. The fibers of the invention have “cotton-like” properties but can be produced as continuous filaments on a year-round basis. The fibers are useful in textile applications.

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 carbon nanotube hybrid system includes: a carbide-derived carbon prepared by reacting a carbide compound and a halogen group containing gas to extract elements of the carbide compound except carbons; metals supported on the carbide-derived carbon or remaining in the carbide-derived carbon; and carbon sources from which carbon nanotubes are grown from the carbide-derived carbon. A method of preparing the carbon nanotube hybrid system includes preparing the carbide-derived carbon, extracting elements therefrom, and growing carbon nanotubes from the carbide-derived carbon. The carbon nanotube hybrid system has excellent uniformity and a long lifetime. An electron emitter having improved electron emitting properties can be inexpensively prepared using the carbon nanotube hybrid system compared to conventional carbon nanotubes. An electron emission device having excellent electron emitting properties can be prepared using the electron emitter.

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.

Graphitic nanofibers, which include tubular fullerenes (commonly called "buckytubes"), nanotubes and fibrils, which are functionalized by chemical substitution, are used as electrodes in electrochemical capacitors. The graphitic nanofiber based electrode increases the performance of the electrochemical capacitors. Preferred nanofibers have a surface area greater than about 200 m2/gm and are substantially free of micropores.

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.

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.

Buckyrock is a three-dimensional, solid block material comprising an entangled network of single-wall carbon nanotubes (SWNT), wherein the block comprises greater than 75 wt % SWNT. SWNT buckyrock is mechanically strong, tough and impact resistant. The single-wall carbon nanotubes in buckyrock form are present in a random network of individual single-wall carbon nanotubes, SWNT “ropes” and combinations thereof. The random network of the SWNT or SWNT ropes can be held in place by non-covalent “cross-links” between the nanotubes at nanotube contact points. In one embodiment, SWNT buckyrock is made by forming a SWNT-water slurry, slowly removing water from the slurry which results in a SWNT-water paste, and allowing the paste to dry very slowly, such that the SWNT network of the SWNT-water paste is preserved during solvent evaporation. Buckyrock can be used in applications, such as ballistic protection systems, involving light-weight material with mechanical strength, toughness and impact resistance.

A composite composition and a method of making such a composite that is composed of a matrix material and dispersed reinforcement nanotubes that are substantially aligned along at least one specified direction or axis. Also a method for making a continuous fiber-reinforced composite object by combining a reinforcement fiber tow with a solidifying matrix material to form a pre-impregnated tow or towpreg, providing a dispensing head capable of dispensing the towpreg onto a base member positioned a distance from this head with the head and base member being driven by motion devices electronically connected to a motion controller regulated by a computer, and operating and moving the head relative to the base member to dispense multiple layers of towpreg in accordance with a CAD-generated deposition path along which the dispensing head can be allowed to trace out individual layers by following a selected algorithm so that the number of path interruptions at which the towpreg must be tentatively cut off from the dispensing head is minimized.

The present invention provides fabrics that have unique chemical, electrical, and thermal properties. The fabrics comprise layers of yarns woven together wherein the yarns further comprise carbon nanotube fibers. These carbon nanotube fibers may be either single-walled or multi-walled carbon nanotubes. The use of carbon nanotube fibers allows the fabrics to insulate, semi-conduct or super-conduct electrical charges. Additionally, the thermal properties of carbon nanotubes allow thermal energy to flow efficiently between the fabric and a heat sink or source. Additional yarns of materials other than carbon nanotubes can be integrated or woven into the fabric to provide other unique properties for the fabric. These fabrics can be layered to form unique garments or structures.

The present invention provides methods for uniform growth of nanostructures such as nanotubes (e.g., carbon nanotubes) on the surface of a substrate, wherein the long axes of the nanostructures may be substantially aligned. The nanostructures may be further processed for use in various applications, such as composite materials. For example, a set of aligned nanostructures may be formed and transferred, either in bulk or to another surface, to another material to enhance the properties of the material. In some cases, the nanostructures may enhance the mechanical properties of a material, for example, providing mechanical reinforcement at an interface between two materials or plies. In some cases, the nanostructures may enhance thermal and/or electronic properties of a material. The present invention also provides systems and methods for growth of nanostructures, including batch processes and continuous processes.

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.

The present invention provides 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. The method comprises (a) dispersing particles of graphite, graphite oxide, or a non-graphite laminar compound in a liquid medium containing therein a surfactant or dispersing agent to obtain a stable suspension or slurry; and (b) exposing the suspension or slurry to ultrasonic waves at an energy level for a sufficient length of time to produce separated nano-scaled platelets. The nano-scaled platelets are candidate reinforcement fillers for polymer nanocomposites. Nano-scaled graphene platelets are much lower-cost alternatives to carbon nano-tubes or carbon nano-fibers.

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.

Field emission display and method for fabricating the same, the field emission display including a cathode array having a cathode electrode formed on a substrate, insulating layers and carbon nanotube films for use as emitter electrodes formed alternately on the cathode electrode, and a gate electrode formed on the insulating layer, thereby permitting fabrication of a large sized cathode plate at a low cost because the film is formed by screen printing and exposure, which can reduce the cumbersome steps in fabrication of the related art Spindt emitter tip, and both a low voltage and a high voltage FEDs because the carbon nanotube film used as the emitter has a low work function, with an easy and stable electron emission capability.

The present invention is directed to methods to harvest, integrate and exploit nanomaterials, and particularly elongated nanowire materials. The invention provides methods for harvesting nanowires that include selectively etching a sacrificial layer placed on a nanowire growth substrate to remove nanowires. The invention also provides methods for integrating nanowires into electronic devices that include placing an outer surface of a cylinder in contact with a fluid suspension of nanowires and rolling the nanowire coated cylinder to deposit nanowires onto a surface. Methods are also provided to deposit nanowires using an ink-jet printer or an aperture to align nanowires. Additional aspects of the invention provide methods for preventing gate shorts in nanowire based transistors. Additional methods for harvesting and integrating nanowires are provided.

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.

An aggregate of carbon-based fine structures in which a plurality of carbon-based fine structures are collected, wherein respective carbon-based fine structures are oriented in the same direction. The above aggregate of carbon-based fine structures is an aggregate of a plurality of carbon-based fine structures in a state they are pulled by one another with strong interaction, and has such a length that allows the improvement of the handleability and workability thereof.

A semiconductor nanowire is grown laterally. A method of growing the nanowire forms a vertical surface on a substrate, and activates the vertical surface with a nanoparticle catalyst. A method of laterally bridging the nanowire grows the nanowire from the activated vertical surface to connect to an opposite vertical surface on the substrate. A method of connecting electrodes of a semiconductor device grows the nanowire from an activated device electrode to an opposing device electrode. A method of bridging semiconductor nanowires grows nanowires between an electrode pair in opposing lateral directions. A method of self-assembling the nanowire bridges the nanowire between an activated electrode pair. A method of controlling nanowire growth forms a surface irregularity in the vertical surface. An electronic device includes a laterally grown nano-scale interconnection.