Abstract: The invention relates to a film comprising greater than 80 wt % single-wall carbon nanotubes wherein the tensile modulus is at least about 6 GPa at 0.2% strain and the conductivity of the film is at least about 70,000 S/m. The tensile modulus is typically about 8 GPa at 0.2% strain. The method for making the film comprises preparing a solution of single-wall carbon nanotubes in a superacid, such as oleum containing approximately 20 to 30% sulfur trioxide, under a dry, oxygen-free atmosphere. The solution is placed on a surface in a moisture-containing atmosphere, wherein the solution absorbs moisture and acid leaches out. The film is washed to further remove acid, dried, and, optionally, subjected to a heat treatment. Besides free-standing films, coatings of single-wall carbon nanotubes can be made on a variety of surfaces including polymers, glass, metals, and ceramics. The surfaces can be flat planes, fibers or contour shapes.

Abstract: A conductive carbon nanotube film having high tensile strength and initial tensile modulus comprises primarily oxidized small-diameter carbon nanotubes wherein the diameter of the small-diameter carbon nanotubes are at most about 3 nm. A method for making the film comprises refluxing an aqueous mixture comprising carbon nanotubes and an oxidizing agent to form a refluxed nanotube dispersion; forming a carbon nanotube film from the refluxed carbon nanotube dispersion; optionally removing nitric acid or other oxidizing agent from the carbon nanotube film; drying the carbon nanotube film; and heat-treating the carbon nanotube film to form a heat-treated carbon nanotube film. The method can also comprise sonicating the nanotubes prior to or after refluxing. A heat-treated small-diameter carbon nanotube film can have a tensile strength of over 70 MPa and an initial tensile modulus of about 5 GPa.

Abstract: The present invention relates to a high modulus macroscopic fiber comprising single-wall carbon nanotubes (SWNT) and an acrylonitrile-containing polymer. In one embodiment, the macroscopic fiber is a drawn fiber having a cross-sectional dimension of at least 1 micron. In another embodiment, the acrylonitrile polymer-SWNT composite fiber is made by dispersing SWNT in a solvent, such as dimethyl formamide or dimethyl acetamide, admixing an acrylonitrile-based polymer to form a generally optically homogeneous polyacrylonitrile polymer-SWNT dope, spinning the dope into a fiber, drawing and drying the fiber. Polyacrylonitrile/SWNT composite macroscopic fibers have substantially higher modulus and reduced shrinkage versus a polymer fiber without SWNT. A polyacrylonitrile/SWNT fiber containing 10 wt % SWNT showed over 100% increase in tensile modulus and significantly reduced thermal shrinkage compared to a control fiber without SWNT.