The present disclosure is directed to the preparation of highly metallic, hydrophilic, polymer-free carbon nanotube (CNT) thin sheets with high tensile strength. The densified CNT sheet has reduced pore sizes, increased tensile strength, and improved electrical conductivity. The disclosed CNT materials can be used as filtration membranes with little or no propensity toward surface fouling. Such densified CNT sheets are also useful as superior electromagnetic interference (EMI) shielding materials.

The present disclosure relates to a carbon nanotube wire includes a carbon nanotube aggregate constituted of a plurality of carbon nanotubes. In the plurality of carbon nanotubes, a mean length of the plurality of carbon nanotubes is not larger than 150 m, a CV value of the mean length is not smaller than 0.40, a mean diameter of the plurality of carbon nanotubes is smaller than 4 nm, a CV value of the mean diameter is not smaller than 0.18, and a proportion of carbon nanotubes with lengths not smaller than 3 m is not less than 60%.

Methods for characterizing a nanotube formulation with respect to one or more particular ionic species are disclosed. Within the methods of the present disclosure, this characterization provides control over the surface roughness (or smoothness) and the degree of rafting within a nanotube fabric formed form such a nanotube formulation. In one aspect, the present disclosure provides a nanotube formulation roughness curve (and methods for generating such a curve) that can be used to select a utilizable range of ionic species concentration levels that will provide a nanotube fabric with a desired surface roughness (or smoothness) and degree of rafting. In some aspects of the present disclosure, such a nanotube formulation roughness curve can be used adjust nanotube formulation prior to a nanotube formulation deposition process to provide nanotube fabrics that are relatively smooth with a low degree of rafting.

A method for making a carbon nanotube composite structure includes the following steps: dispersing a plurality of carbon nanotubes in water, to form a carbon nanotube dispersion; adding an aniline solution into the carbon nanotube dispersion, to form a mixed solution; adding an initiator into the mixed solution, to form a carbon nanotube composite structure preform; freeze-drying the carbon nanotube composite structure preform in a vacuum environment; and carbonizing the carbon nanotube composite structure preform in a protective gas after freeze-drying. The present application also relates to the carbon nanotube composite structure.

The present disclosure provides systems and methods for producing a volume of substantially all armchair nanotubes of a preselected chirality for fabricating yarn consisting of substantially all metallic conducting armchair tubes. The systems and methods can be used for the synthesis of (10,10), (11,11), and (12,12) metallic armchair carbon nanotubes and potentially other chiralities. The elements of the present disclosure include: (i) a carbon source that provides substantial numbers of ethylene and acetylene radicals in combination with a high population of ethylene groups and a small amount of methane, (ii) a hydrogen to carbon ratio sufficient to passivate all other chiral growth sites to a higher degree than armchair growth sites, and (iii) a CVD process that can be tuned to create a well-controlled population of catalyst with tight diameter distribution with sparse modal distribution that falls within a range of the desired single wall diameters.

A hydrophilic graphitic material is provided that may be formed by heating a graphitic material to a temperature between about 150 C. to about 1400 C. for an extended period of time under an inert atmosphere. Annealing CNT film at 500 to 1400 removes amorphous carbon to produce purified CNT film. The purified CNT film can be further densified with the treatment of alkylphosphonic acid or alkyldiphophonic acid and heating to produce a hydrophilic, densified CNT film which is mechanically robust and does not adhere to other solid surfaces. These films can be used as filtration membranes with superior membrane fouling resistance among other uses.

A method for making a carbon nanotube composite structure includes the following steps: dispersing a plurality of carbon nanotubes in water, to form a carbon nanotube dispersion; adding an aniline solution into the carbon nanotube dispersion, to form a mixed solution; adding an initiator into the mixed solution, to form a carbon nanotube composite structure preform; freeze-drying the carbon nanotube composite structure preform in a vacuum environment; and carbonizing the carbon nanotube composite structure preform in a protective gas after freeze-drying. The present application also relates to the carbon nanotube composite structure.

A method for separating a single-walled carbon nanotube mixture includes: preparing a dispersion liquid containing the single-walled carbon nanotube mixture and a surfactant; and separating the single-walled carbon nanotube mixture contained in the dispersion liquid, wherein in the separating the single-walled carbon nanotube mixture, a dispersion liquid in which a physical property of the dispersion liquid is within a prescribed range is used.

A method for making a carbon nanotube composite structure includes the following steps: dispersing a plurality of carbon nanotubes in water, to form a carbon nanotube dispersion; adding an aniline solution into the carbon nanotube dispersion, to form a mixed solution; adding an initiator into the mixed solution, to form a carbon nanotube composite structure preform; freeze-drying the carbon nanotube composite structure preform in a vacuum environment; and carbonizing the carbon nanotube composite structure preform in a protective gas after freeze-drying. The present application also relates to the carbon nanotube composite structure.

The present invention relates to a method for enhancing tensile strength of a carbon nanotube (CNT) fiber aggregate, comprising dispersing a CNT fiber aggregate with chlorosulfonic acid (CSA), followed by thermal treatment, wherein a particular magnitude of tension is applied upon the thermal treatment, whereby the CNT fiber aggregate is increased in alignment level and tensile strength.