Enhanced piezoelectric performance of Al/P(VDF-TrFE) nanocomposite films for energetic sensors and ignitors

Abstract

Piezoelectric polymers and ceramics are widely used as pressure sensors and transducers. Among polymers, poly(vinylidene fluoride—trifluoroethylene) [P(VDF-TrFE)] stands out for its superior piezoelectric performance. When combined with aluminum nanopowders (nAl), it forms an energetic composite known as a piezoenergetic, capable of mechanical-to-electrical energy conversion and energetic response. However, poling such composites is challenging due to shorting and leads to a reduced piezoelectric coefficient (d33). In this work, we develop and characterize single-layer and multilayer P(VDF-TrFE)-based composite films with enhanced piezoelectric and energetic properties. We show that thermal annealing and high temperature poling enable 9 wt. % nAl/P(VDF-TrFE) films to reach a d33 of 22.7 pC/N, comparable to commercial P(VDF-TrFE) films. Incorporating barium titanate (BaTiO3) is shown to also increase the d33 coefficient with 200 nm particles outperforming micrometer-scale particles. Additionally, we fabricate hot-pressed, three-layer “sandwich” composites with a 30 wt. % nAl core layer and P(VDF-TrFE) outer layers, achieving higher energetic performance despite a marginal reduction in d33 coefficient. We demonstrate the ignition of sandwich samples using an electrical discharge, rendering these films suitable for ignition applications. Finally, single-layer and sandwich films were calibrated and demonstrated as pressure gauges using a mini drop-weight setup. The improvements in d33 of the 9 wt. % nAl/P(VDF-TrFE) single-layer films, as well as the energetic performance in the form of the 30 wt. % nAl/P(VDF-TrFE) sandwich films strongly amplify the existing potential of these multifunctional composites in energetic and pressure sensing applications.