SANS investigation of piezoelectric polymer assembly under combined ultrasound and electrical fields

Poly(Vinylidenediflouride) (PVDF) is a high performance polymer used in a multitude of applications such as filtration membranes, high temperature structural components, sensors, actuators and energy storage. The polymer exhibits 5 phase conformations, 3 of which are piezoelectric. Of all, the beta-phase has the highest piezoelectric response due to zigzag planar chain conformation. To synthesise this phase, mechanical or thermal treatment is typically used on the alpha phase form. However, ultrasound, with its capacity to generate cavitation on a small spatial scale, presents an efficient energy source for reorienting the polymer chains. This approach enables the formation of the desired (beta-phase) zigzag conformation by overcoming the crystallisation energy barrier. In addition, being semi-crystalline polymer, precise control of the amount, size distribution of the beta-phase crystallinity is critical for applications such as sensor,actuator design as it increase di-polar moments per volume. Understanding the time evolution of crystal structure and beta-phase conformation is critical to increase the beta-phase using energy efficient technique. The PI of the proposal has previously received early career research grant funding from The Royal Society (RGS\R2\222100) on advanced processing methods for high performance polymer sensors for condition monitoring applications in the offshore energy sector. The PI currently is supervising a PhD student on this research.