Carbon nanotubes are a special form of carbon that can be both highly conductive and extremely stronger for their weight. In fact, at just a sixth the weight, carbon nanotubes are 100 times stronger than steel, which is part of the reason why researchers have been trying to make them into large scale fibers. After over a decade of work, researchers at Rice University have successfully developed a scalable method to produce such fibers.
Part of the reason this research took so long is that nanotubes are very difficult to work with, and it took almost a decade for scientists to find a way to produce bulk quantities of them. Once the Rice researchers had enough nanotubes they then had to optimize their wet-spun method, which dissolves the nanotubes into a solvent that is extruded through a nozzle. The extruded threads are then rolled onto a drum and made into the fiber. Finding the solvent itself was a major breakthrough as it allowed for the creation of the highly concentrated nanotube solutions needed for the wet-spun technique.
To look at the nanotube fiber, one would believe it is just black thread, and in some ways it behaves like a textile thread, but not all ways. The fibers are as electrically and thermally conductive as copper wires but are still very strong, which will be useful for low-power situations. Typical metal wires used in such situations are often thicker than electrically needed because if they were any thinner, production machinery would break them.