The present invention relates to carbon nanotubes that are excellent in dispersibility and a process for producing the carbon nanotubes. The carbon nanotubes according to the present invention each comprise a wall that comprises a parallel portion and a narrowed portion having a tube outer diameter that is not more than 90% of a tube outer diameter of the parallel portion. Thus, the carbon nanotubes are readily dispersible owing to a high abundance ratio of easily-breaking portions.

The present invention relates to a method for separating semi-conducting and metallic single-walled carbon nanotubes from each other and, if present, from other carbonaceous material, or for separating semi-conducting or metallic single-walled carbon nanotubes from other carbonaceous material via density separation using a solution of a polytungstate; to semi-conducting or metallic single-walled carbon nanotubes obtained by this method; and to the use of these semi-conducting or metallic single-walled carbon nanotubes. The invention further relates to the use of a polytungstate, particularly sodium polytungstate, for separating semi-conducting single-walled carbon nanotubes from metallic single-walled carbon nanotubes, or for separating semi-conducting single-walled carbon nanotubes from undesired carbonaceous material, particularly from metallic single-walled carbon nanotubes, or for separating metallic single-walled carbon nanotubes from undesired carbonaceous material, particularly from semi-conducting single-walled carbon nanotubes. The invention also relates to specific polyarylethers containing phosphate groups and their use as surface-active compounds.

Achieved is a coating floor material using a carbon nanotube, which has excellent finishing properties and shows high conductivity even when a cured coating film is at 50 V. This coating floor material contains: a room temperature curable resin, a single-walled carbon nanotube, a wetting dispersant, a leveling agent, and a defoaming agent, wherein the wetting dispersant is a polymer salt containing an acidic group and an amino group.

A method for in-situ measuring electrical properties of carbon nanotubes includes placing a first electrode in a chamber, wherein the first electrode defines a cavity. A growth substrate is suspend inside of the cavity, and a catalyst layer is located on the growth substrate. A measuring meter having a first terminal and a second terminal opposite to the first terminal is provided. The first terminal is electrically connected to the first electrode, and the second terminal is electrically connected to the growth substrate. A carbon source gas, a protective gas, and hydrogen are supplied to the cavity, to grow the carbon nanotubes on the catalyst layer. The electrical properties of the carbon nanotubes are obtained by the measuring meter.

The present invention provides methods for purifying a layer of carbon nanotubes comprising providing a precursor layer of substantially aligned carbon nanotubes supported by a substrate, wherein the precursor layer comprises a mixture of first carbon nanotubes and second carbon nanotubes; selectively heating the first carbon nanotubes; and separating the first carbon nanotubes from the second carbon nanotubes, thereby generating a purified layer of carbon nanotubes. Devices benefiting from enhanced electrical properties enabled by the purified layer of carbon nanotubes are also described.

The present invention relates to a process for synthesizing carbon nanotubes by continuous chemical vapor deposition at the surface of reinforcements, said reinforcements constituting a mixture A (i) of particles and/or fibers of a material comprising at least one oxygen atom and (ii) of particles and/or fibers of a material chosen from carbides and/or of a material comprising at least one silicon atom, said process comprising the following steps, carried out under a stream of inert gas(es) optionally as a mixture with hydrogen: (i) heating of said mixture of reinforcements A in a reaction chamber at a temperature ranging from 400° C. to 900° C.; (ii) introducing into said chamber a source of carbon consisting of acetylene and/or xylene, and a catalyst comprising ferrocene; (iii) exposing said heated mixture A to the source of carbon and to the catalyst comprising ferrocene for a sufficient time to obtain carbon nanotubes at the surface of the reinforcements constituting said mixture A; (iv) recovering a mixture B at the end of step (iii), optionally after a cooling step, said mixture B consisting of the mixture (A) of reinforcements comprising carbon nanotubes at their surface; (v) optionally, separation (a) of the particles and/or fibers of a material comprising at least one oxygen atom, (b) of the particles and/or fibers of a material chosen from carbides and/or of a material comprising at least one silicon atom.

The present invention discloses single-walled carbon nanotubes horizontal arrays with ultra-high density and the preparation method. The method comprises the following steps: loading a catalyst on a single crystal growth substrate; after annealing, introducing hydrogen into a chemical vapor deposition system to conduct a reduction reaction of the catalyst; and maintaining the introduction of the hydrogen to conduct the orientated growth of a single-walled carbon nanotube. The density of the ultra-high density single-walled carbon nanotube horizontal array obtained by this method exceeds 130 tubes/micrometer, and an electrical performance test is performed on the prepared ultra-high density single-walled carbon nanotube horizontal array shows a high on-current density of 380 μA/μm, and the transconductance of 102.5 μS/μm.

Various embodiments of the present disclosure pertain to methods of making carbon nanotube-coated substrates by dissolving carbon nanotubes in a solvent to form a carbon nanotube solution; and coating a surface of a substrate with the carbon nanotube solution to form one or more carbon nanotube layers on the surface of the substrate. The carbon nanotube solution may include a superacid solvent. A cable made out of the carbon nanotube-coated substrates may include one or more internal insulating layers that surround the surface of one or more internal conductors. Carbon nanotube solutions may be coated onto the one or more internal insulating layers to form one or more carbon nanotube layers. Additional embodiments of the present disclosure pertain to carbon nanotube-coated substrates formed by the methods of the present disclosure. The carbon nanotube-coated substrates may include one or more carbon nanotube layers derived from a carbon nanotube solution.

Cohesive carbon assemblies are prepared by obtaining a functionalized carbon starting material in the form of powder, particles, flakes, loose agglomerates, aqueous wet cake, or aqueous slurry, dispersing the carbon in water by mechanical agitation and/or refluxing, and substantially removing the water, typically by evaporation, whereby the cohesive assembly of carbon is formed. The method is suitable for preparing free-standing, monolithic assemblies of carbon nanotubes in the form of films, wafers, discs, fiber, or wire, having high carbon packing density and low electrical resistivity. The method is also suitable for preparing substrates coated with an adherent cohesive carbon assembly. The assemblies have various potential applications, such as electrodes or current collectors in electrochemical capacitors, fuel cells, and batteries, or as transparent conductors, conductive inks, pastes, and coatings.

This present invention relates to oxidized, discrete carbon nanotubes in dispersions, especially for use in printing inks. The dispersions can include materials such as elastomers, thermosets and thermoplastics or aqueous dispersions of open-ended carbon nanotubes with additives. A further feature of this invention relates to the development of a dispersion of oxidized, discrete carbon nanotubes that are electrically conductive.