Macroscopic Fibers of Well-Aligned Carbon Nanotubes by Wet Spinning

A simple process to spin fibers consisting of multi‐walled carbon nanotubes (CNTs) directly from their lyotropic liquid‐crystalline phase is reported. Ethylene glycol is used as the lyotropic solvent, enabling a wider range of CNT types to be spun than previously. Fibers spun with CNTs and nitrogen‐doped CNTs are compared. X‐ray analysis reveals that nitrogen‐doped CNTs have a misalignment of only ±7.8° to the fiber axis. The tensile strength of the CNT and nitrogen‐doped CNT fibers is comparable but the modulus and electrical conductivity of the are lower. The electrical conductivity of both types of CNT fibers is found to be highly anisotropic. The results are discussed in context of the microstructure of the CNTs and fibers. In a spin: Fibers are spun from liquid‐crystalline dispersions of pure and nitrogen‐doped carbon nanotubes (CNTs) in glycerol using a coagulation wet spinning process. The N‐doped CNT fibers (see image) have the highest packing density due to a high degree of straightness of the particular type of doped tube used. This dense microstructure results in a higher strength, elastic modulus, and electrical conductivity than the pure CNT fibers.