Alignment of Carbon Nanotubes in Macroscopic Fibers

A simple spinning process has been recently developed to assemble carbon nanotubes into long macroscopic fibers. Due to the high aspect ratio of the nanotubes, the fiber’s physical properties are expected to depend significantly on the nanotube orientation. The alignment of the nanotubes is studied by X‐ray scattering. It is characterized by the Full Width at Half Maximum (FWHM) of the azimuthal intensity distribution. Our first studies gave FWHM≈75°. Treatments developed to improve nanotube alignment, such as solvent‐wetting or drawing of the fibers, are reported here. Results obtained from nanotubes synthesized by the arc‐discharge method and by the HiPCO process are discussed. Stretched fibers processed with HiPCO single‐wall nanotubes exhibit FWHMs as low as 32°. Moreover, the above‐mentioned treatments induce a substantial increase (by a factor 4) of their Young’s modulus. An example of electromechanical actuation is reported.