A research team led by Professor Yong-Hoon Kim from the KAIST Graduate School of Energy, Environment, Water and Sustainability (EEWS) has investigated the characteristics of the atomic and electronic structures of low-tech carbon nanomaterial interfaces and the polymer precursor for the development of high-quality carbon fiber. This research is anticipated to provide a theoretical blueprint for the development of next-generation carbon fiber. The results of this research, with PhD student Juho Lee as the lead author, have been published in the April 11 publication of Advanced Functional Materials.

Carbon fiber is very light and has excellent mechanical and thermal properties. It is therefore a novel material actively adopted in uses ranging from sports equipment like golf clubs and bicycles to high-tech applications in aerospace engineering and nuclear energy. It is acquired by the radiation, stabilization, and carbonization of precursor polymers, most commonly polyacrylonitrile (PAN). And for the acquisition of next-generation carbon fiber of higher quality, dispersing a carbon nanotube (CNT) on a carbon fiber precursor polymer matrix to enhance the crystallizability of the polymer is typical.

However, despite continued research for more than 20 years, little is understood of the interactions between the CNT and the precursor polymer due to experimental difficulties. Thus, high-quality carbon fiber production from the CNT had been limited.

Using a supercomputer, Professor Kim’s research team carried out a multiscale simulation based on the first principles of quantum mechanics, which systematically reproduced the process of PAN polymer arrangement on the CNT interface. The team also studied the reason behind the CNT-PAN interface demonstrating a particularly favourable nature and uncovered that PAN prefers a particular atomic structure in which the monomers are lying on their sides. As a result, the positive and negative charges showed balanced movements, which are also a characteristic nature of the interface. Maximizing the structure of this interface was then proven to induce the optimum large-scale PAN arrangement. Furthermore, the team confirmed that PAN polymer arrangement was optimized in its interface with graphene nanoribbon, which suggested the possible use of graphene to enhance the quality of carbon fiber.

“This research is an example of a quantum mechanics-based computer simulation providing the basis of the theory for the development of high-tech material,” remarked Professor Kim. “The importance of computer simulations will grow alongside the rapid development of computer performance and simulation theory structure,” he added.