Strategies for improving positive temperature effects in conductive polymer composites – a review

Abstract

Conductive polymer composites (CPCs) with a positive temperature coefficient (PTC) have received considerable attention in the intelligent electric heating field due to their low cost, chemical stability, flexibility, and formability compared to conventional inorganic ceramic PTC composites. To fabricate high-performance PTC composites for application, considerable efforts have been made to improve the overall PTC performance of CPCs in both academia and industry. However, few reviews are focusing on the systematic summary and discussion regarding the research strategies to improve the PTC performance of CPCs. In this review, the conductive mechanism and PTC effect mechanism of CPCs with the PTC effect are first summarized. Then, the research strategies to regulate the PTC performance of CPCs are systematically reviewed in terms of the polymer matrix, conductive fillers, and preparation processes. CPCs with a crystalline polymer and an amorphous polymer as the matrix are reviewed separately, especially for the former due to their current widespread application in PTC composites. Meanwhile, the various research strategies for improving the PTC performance are analyzed and summarized. The current challenges and future outlook in this field are also discussed. The research strategies reviewed here for improving the PTC performance of CPCs can provide a comprehensive guide for researchers seeking high-performance PTC composites.