Role of polyphosphazene in piezoelectric applications: A review

Materials exhibiting piezoelectric and pyroelectric properties are extensively employed in various industries, including automotive, computer technology, medical devices, military applications, and consumer goods, serving as sensors and actuators. Piezoelectric materials play a crucial role in transducers, surface acoustic wave (SAW) devices, and piezoelectric sensors, particularly in aerospace for structural health monitoring purposes. There are many piezoelectric polymers available viz. collagen, cellulose, silk, PVDF, copolymers of PVDF with trifluoroethylene and tetrafluoroethylene, etc. that exhibit piezoelectric properties. Polyphosphazene (PPZ) which is a smart multifunctional material behaves as a potential candidate in designing piezoelectric materials by incorporating organic moieties in the PPZ backbone. Organophosphazene in the form of polymeric crosslinked networks or polymer composites with other polymer matrices exhibits remarkable piezoelectric energy harvesting applications. This review summarizes the properties, mathematical theories, and structural requirements of piezoelectric polymers along with a brief discussion of the synthesis and application of polyphosphazenes in the area of piezoelectricity.