UC Irvine

Carbon nanofibers show the advantages of scale effects on electrical and mechanical properties for applications such as aerospace1,2, automotive3,4, and energy5,6, but have to confront the challenge of maximizing the role of scale effects. Here, a method of additive nanostructuring and carbonization of polyacrylonitrile (PAN) jetting for the nano-forming of carbon fibers is developed by understanding the electrostatic submicro-initiation of a PAN jetting, altering the microstructure of PAN-based jetting fibers at the nanoscale and implementing subsequent carbonization of PAN jetting nanofiber. Using this method of additive nanostructuring and carbonization in combination with the radial distribution pattern of shear stress, we find that the conformation of some molecular chains inside the PAN nanofibers is transformed into the zigzag conformation. The ability to materialize and carbonize such PAN nanofibers with various conformational structures in the form of arrays on diverse micro-structures and macro-substrates enables the forming of continuous carbon nanofibers with a diameter of ~20 nm and allows the tensile strength of carbon fibers to be enhanced to 212 GPa through the combination of zigzag conformation and nanoscale effects. These advantages create opportunities for the application of maximizing nanoscale effects that have not previously been technically possible.