High-temperature-resistance flexible piezoelectric sensor via cyclized PAN/BTO nanofibers

Abstract

Maintaining stable sensing performance in extreme environments, such as high temperatures, is critical for accurate signal monitoring. Conventional rigid sensors fail to fit on uneven surfaces and polymer-based piezoelectric sensors degrade at elevated temperatures, restricting their utilization in harsh environments. Herein, we design a flexible and high-temperature-resistant piezoelectric sensor based on cyclized polyacrylonitrile (PAN) and barium titanate (BTO) nanoparticles. Computational and experimental results indicate that the integration of BTO into the PAN matrix increases the interfacial dipole interactions and raises the activation energy of the PAN cyclization reaction ($E_a$ = 221.63 kJ/mol). As a result, the developed sensor exhibits a broad operating temperature range (room temp. to 500 °C), an improved piezoelectric performance ($d_{33}$ = 41.5 pC/N), a remarkable frequency response (500 Hz), and an excellent flame-retardant property ($\mathrm{LOI}$ = 40 %). Supported by machine learning algorithms, the PAN/BTO fiber-based monitoring system achieves accurate fault diagnosis in high-temperature mechanical vibration scenarios, with an impressive accuracy of 96 %. This innovative approach paves the way for designing unique high-temperature-resistant materials and flexible piezoelectric sensors for real-time sensing under harsh conditions.