Multifunctional Poly( p ‐Phenylene Benzobisoxazole) Nanofiber Composite Films for High‐Performance Sensors, Heaters, and Electrodes

ABSTRACT This study presents the fabrication of ultrathin, mechanically strong poly( p ‐phenylene benzobisoxazole) (PBO) nanofiber films and their integration into composite materials. A novel sol‐gel‐film method was established for producing PBO nanofiber films, with an orthogonal experimental design employed to optimize the effects of PBO concentration and dissolution time on the mechanical properties. The optimal conditions (PBO concentration of 2.8 g/L and dissolution time of 40 h) yielded a tensile strength of 683 MPa and a Young's modulus of 12.05 GPa. Furthermore, PBO nanocomposite films incorporating silver nanoparticles (Ag NPs) were developed. The PBO/Ag nanocomposite film with 10% Ag NPs content exhibited notable mechanical properties, with a tensile strength of 239 MPa and a Young's modulus of 5.91 GPa, and an exceptional electrical conductivity of 401.6 S/cm. The nanocomposite films also demonstrated enhanced hydrophobicity, UV resistance, antibacterial properties, and flame retardancy. Pressure sensors based on the PBO/Ag nanocomposite films showed high sensitivity and stability, whereas electric heaters exhibited remarkable heat resistance, rapid response times, and elevated heating temperatures. Additionally, a polyaniline (PANI) coating doped with carbon nanotubes (CNTs) was synthesized on the PBO/Ag nanocomposite films, resulting in flexible PBO/Ag@PANI/CNT electrodes. These electrodes, with 30% CNTs, achieved an impressive areal capacitance of 6885.13 mF/cm 2 and maintained 82.67% of their initial capacitance after 5000 charge‐discharge cycles. These findings highlight the significant potential of PBO nanofiber‐based nanocomposites in flexible electronics and advanced energy storage systems.