Property Enhancement of Direct-Spun Carbon Nanotube Fibers via Polyethylene Glycol Infiltration

Carbon nanotube (CNT) fiber is a promising material for various applications, such as wearable devices, energy harvesting, energy storage, and artificial muscles. The floating catalyst chemical vapor deposition (FCCVD) method allows mass production of CNT fibers. However, the mechanical and electrical properties of the CNTs fabricated using the FCCVD method are inferior to those of the CNT fibers fabricated using other methods, such as wet spinning and spinnable CNT forests. Therefore, suitable methods are required to improve the mechanical properties and electrical conductivity of CNT fibers obtained using the FCCVD method. One strategy is infiltration of a polymer into the CNT fiber. In this study, polyethylene glycol was infiltrated into pristine CNT fibers and formed hydrogen bonds with the oxygen present on surface of CNTs from FCCVD method. Solvent evaporation resulted in the formation of dense CNT fibers, which featured more connections among the CNTs. The polymer-incorporated CNT fiber exhibited high toughness, ultimate strength, and electrical conductivity and can thus be employed in various real-life applications.