Large-Scale Nanofiber Manufacturing| High-temperature-resistance flexiblepiezoelectric sensor via cyclized PAN/BTOnanofibers

Southwest Jiaotong University Associate Professor Wei-Li Deng: PAN/BTO Nanofiber-Based Flexible Piezoelectric Sensor with High-Temperature Resistance

Long-term operation of equipment in high-temperature extreme environments often involves intense mechanical vibrations, posing higher demands for vibration monitoring technology. In fields such as aerospace, energy equipment, petroleum exploration, and industrial monitoring, traditional flexible piezoelectric sensors face the technical bottleneck of thermal degradation failure, making it difficult to meet long-term monitoring needs in high-temperature environments. Currently, rigid piezoelectric sensors perform well in certain applications, but their large size and limited flexibility restrict their use on complex curved surfaces, dynamic components, and microstructures. Therefore, developing sensing materials that combine high-temperature stability, excellent piezoelectric properties, and good mechanical flexibility is crucial for vibration monitoring in extreme environments.

Recently, a team led by Associate Professor Wei-Li Deng and Professor Wei-Qing Yang from the School of Materials Science at Southwest Jiaotong University, in collaboration with Professor Li-Hua Tang’s team at the University of Auckland, New Zealand, innovatively proposed a high-temperature piezoelectric regulation mechanism based on cyclized polyacrylonitrile/barium titanate (PAN/BTO) composite nanofibers. They successfully developed a new flexible piezoelectric sensing material with both high-temperature stability and excellent piezoelectric performance (operating temperature up to 500 °C), offering a promising solution for vibration monitoring and structural health monitoring in high-temperature environments. The related research results were published in the internationally renowned journal Nano Energy under the title "High-temperature-resistance flexible piezoelectric sensor via cyclized PAN/BTO nanofibers." Ting-Ting Zhou, a 2023 master's student at the School of Materials Science, was the first author, and Associate Professor Wei-Li Deng was the corresponding author. The research was supported by the National Natural Science Foundation of China, the Sichuan Science and Technology Program, and the Southwest Jiaotong University Fundamental Research Fund.

Figure 1: Design of high-temperature-resistant PAN/BTO nanofibers.

The research team introduced barium titanate (BTO) nanoparticles into a polyacrylonitrile (PAN) matrix and optimized the high-temperature piezoelectric properties of the material by regulating the cyclization reaction and molecular chain configuration. Characterization techniques such as transmission electron microscopy (TEM), scanning electron microscopy (SEM), and X-ray diffraction (XRD) were used to systematically analyze the distribution of BTO nanoparticles in the PAN matrix and the microstructural evolution of the material. Additionally, electrostatic potential simulations were employed to study the thermal stability and polarization behavior of pure PAN and PAN/BTO nanofibers during thermal annealing. The results showed that the introduction of BTO effectively increased the cyclization temperature of PAN and enhanced the high-temperature piezoelectric response, providing new theoretical and experimental support for the design of high-temperature flexible piezoelectric sensing materials.

Figure 2: Characterization and analysis of PAN/BTO nanofibers.

Further research revealed that the introduction of BTO nanoparticles effectively regulated the cyclization kinetics of PAN, significantly improving the material's thermal stability. Even at 500 °C, the composite nanofibers maintained excellent flexibility and stable piezoelectric response. Additionally, thermal annealing enhanced the material's flame retardancy, significantly increasing its flame retardant coefficient, thereby improving the safety of high-temperature sensors and providing strong support for their applications in extreme environments.

Figure 3: High-temperature electrical and flame-retardant properties of PAN/BTO nanofibers.

To validate the practical potential of PAN/BTO nanofibers, the research team developed a machine learning-based intelligent vibration monitoring system and applied it to the fault diagnosis of air compressor vibrations. The system integrated high-temperature-tolerant sensors to collect real-time vibration signals in extreme environments and employed a Temporal Convolutional Network (TCN) algorithm for efficient data processing and pattern recognition. Experimental results demonstrated that the system could accurately classify different types of vibration faults, exhibiting exceptional high-temperature adaptability and long-term operational stability, offering an innovative solution for equipment health monitoring in extreme environments.

Figure 4: A deep learning-assisted real-time mechanical vibration monitoring system.

Original link: https://doi.org/10.1016/j.nanoen.2025.110910