A review: Polyacrylonitrile as high-performance piezoelectric materials

Piezoelectric polymer materials have been extensively investigated as key materials for small kinetic energy harvesting due to their advantages over inorganic piezoelectric materials, such as high flexibility, good processability, and the possibility of a large area as well as curved surface preparation. However, the difficulty of working at high temperatures is a huge challenge for polymeric piezoelectric materials. Therefore, researchers have not stopped their quest to develop new piezoelectric polymer materials with higher performance. This paper first describes the design mechanism of piezoelectric polyacrylonitrile (PAN), analysing its structure and fabrication techniques, as well as its advantages, problems, and structural design challenges. Subsequently, methods to improve the high-temperature piezoelectric properties of PAN by changing the molecular structure and blending with inorganic materials/high-temperature resistant polymers are presented. Research on the application of PAN piezoelectric polymers in nanogenerators, acoustoelectric conversion, sensors, and high temperature thermoacoustic conversion are summarized. Finally, the status, problems, and potential of PAN high-temperature piezoelectric polymers are revealed, and the future directions of various PAN properties in different fields are foreseen.