Flexible pressure sensor based on Pt/PI network with high sensitivity and high thermal resistance

•A Pt/PI fibrous network is fabricated by electrospinning and ion-sputtering for the piezoresistive sensor.•The piezoresistive sensor possesses remarkable sensitivity under room and high temperatures.•The piezoresistive sensor can be applied in human physiological monitoring and pressure detection in harsh environments. The increasing development of wearable electronics necessitates the urgent need for highly sensitive flexible pressure sensors suitable for harsh environments at high/low temperatures, thus meeting the specific requirements of wilderness survival, lunar exploration, mine exploration, and so on. Herein, a flexible piezoresistive sensor based on 3D Pt/PI fibrous network is prepared through the electrospinning and ion-sputtering techniques, demonstrating excellent sensing performance over a wide temperature range from liquid nitrogen temperature to 250 °C. The 3D Pt/PI pressure sensor achieves high sensitivity of 158.23 kPa−1 at room temperature, and remains remarkable sensitivity of 71.47 kPa−1 and 7.63 kPa−1 at 150 °C and 250 °C, respectively. Furthermore, benefiting from the hydrophobicity of the Pt/PI fibrous network, the sensitivity of the pressure sensor stabilizes in about 148 ± 10 kPa−1 under relative humidity from 30 % to 90 %, indicating humidity-independent sensing performance. As a proof of concept, the fabricated piezoresistive sensor can be not only monitor the human physiological information in real-time, but also detect external mechanical stimuli at high/low temperatures, demonstrating great potential for application in harsh environments.