Hanyang University professor Kim Sun-jung’s research team has developed a graphene-carbon nanotube hybrid fiber that is at least 12 times stronger and more flexible than general synthetic fiber used in manufacturing bulletproof jackets.
It is difficult to turn graphene, which has the form of a flat plate, into a fiber, although the material has strong mechanical properties, high electric conductivity, and can be manufactured at a low cost. Also, carbon nanotube fibers require complex post-processing due to the tangling that occurs during the course of fiber production.
However, the research team maximized the wrinkled structure by dispersing graphene in water and conducted wet spinning in a polymer solution to obtain a fiber form. The polymer was removed from the graphene-polymer composite fiber that is produced in this way for the production of a graphene-only fiber. At the same time, self-assembly was induced during the wet spinning based on the graphene-carbon nanotube mixing, so that the hybrid fiber can be produced without post-processing.
The product has 10 times the mechanical strength when compared to a case in which a single nanomaterial is used. The factor is six and 12 compared to spiderwebs and Kevlar, respectively. It is resistant to torsion, durable, flexible enough to allow sewing, and can be molded into a high-strength spring form. The possible applications include light vehicles, aerospace equipment, national defense, and composite materials. In addition, the wrinkled graphene coupling allows it to be used in artificial muscles. The team is going to commercialize it with the assistance of the Ministry of Science, ICT and Future Planning.
“The hybrid fiber can be used in a wide variety of industrial fields,” the professor explained, adding, “I hope that our development will contribute to advancing the textile industry of Korea with developed countries refraining from transfering high-performance fiber technology these days.”