The enhanced power factor of multi-walled carbon nanotube/stabilized polyacrylonitrile composites due to the partially conjugated structure

The studies of organic thermoelectric (TE) materials mainly focus on conductive polymers due to their conjugated molecular structures and high intrinsic electrical conductivity. When the conductive polymer is mixed with certain insulating polymers, the power factor was found enhanced. It is doubtful that the partially conjugated molecular structure is beneficial to the TE performance. Polyacrylonitrile (PAN) is an insulating polymer with a non-conjugated structure in its backbone, however, it has a partially conjugated structure after thermal treatment. In this work, a composite of PAN and multi-walled carbon nanotubes (MWCNT) was made and thermally treated in order to study the partially conjugated structure on the improvement of the power factor. By controlling the PAN content and the temperature of thermal treatments, a maximum power factor of 22 mW/mK(2) was obtained from the MWCNT/PAN composite with 45% PAN content after thermally treated at 300 degrees C in air, which is 300% and 80% higher than that without PAN and before thermal treatment, respectively. It is demonstrated that the partially conjugated polymers play an important role in TE performance and they are promising candidates for high-efficient organic TE materials. (C) 2020 The Chinese Ceramic Society. Production and hosting by Elsevier B.V.

Automated summary

The studies focus on conductive polymers, with partially conjugated structures showing enhanced power factor and improved TE performance after thermal treatment. Controlling PAN content and temperature during thermal treatments can significantly increase the power factor of the composite materials. Conclusively, partially conjugated polymers play a crucial role in enhancing TE performance and are promising candidates for efficient organic TE materials.