Macroscopic fibres made up of carbon nanotubes exhibit properties far below theoretical predictions and even much lower than those for conventional carbon fibres. Here we report improvements of mechanical and electrical properties by more than one order of magnitude by pressurized rolling. Our carbon nanotubes self-assemble to a hollow macroscopic cylinder in a tube reactor operated at high temperature and then condense in water or ethanol to form a fibre, which is continually spooled in an open-air environment. This initial fibre is densified by rolling under pressure, leading to a combination of high tensile strength (3.76–5.53 GPa), high tensile ductility (8–13%) and high electrical conductivity ((1.82–2.24) × 10^4 S cm−1). Our study therefore demonstrates strategies for future performance maximization and the very considerable potential of carbon nanotube assemblies for high-end uses.
Carbon nanotubes (CNTs) are microscopic fibers that look like porous straws and are consistently described, along with their sister carbon structure graphene, as the strongest, lightest and most conductive (electrically and thermally) material known to man. At the individual carbon nanotube level, these fibers are: 200X the strength and 5X the elasticity of steel; 5X the electrical conductivity (“ballistic transport”), 15X the thermal conductivity and 1,000X the current capacity of copper; at almost half the density of aluminum. Historically, commercial carbon nanotube makers have produced and marketed short length fibers with limited properties and, in turn, limited applications and a hard to integrate raw material.
Nanocomp’s CNTs are millimeters in length – 1000s of times longer than all other commercial CNT makers