Engineering Heat Transport in Poly( p -phenylene benzobisoxazole) Fiber-Based Materials: Advances, Limitations, and Perspectives

Poly( p -phenylene benzobisoxazole) (PBO) fiber-based materials have attracted increasing attention in advanced thermal management owing to their exceptional thermal stability, mechanical strength, and chemical robustness. This review discusses recent progress in high-thermal-conductivity PBO-based materials by linking structural design principles with emerging engineering requirements. It first outlines the synthesis of PBO microfibers and nanofibers, emphasizing how bottom-up and top-down strategies regulate molecular orientation, crystallinity, and nanoscale morphology. Building on these structural features, the review then examines highly thermally conductive PBO films, all-polymer composites, and multifunctional composites containing electrically conductive or insulating fillers. Particular attention is given to interfacial engineering, which plays a key role in reducing phonon scattering and enabling efficient heat transport across multicomponent systems. Representative applications in electronics, electrical insulation, energy storage, and thermal regulation under extreme conditions are further discussed. Finally, current challenges and future opportunities are highlighted, including sustainable nanofiber production, standardized performance evaluation, and mechanism-guided interfacial design, providing guidance for developing next-generation PBO-based thermal management materials.