  Poly(vinylidene fluoride) (PVDF) has long been regarded as an ideal
piezoelectric plastic because it exhibits a large piezoelectric response and a
high thermal stability. However, the realization of piezoelectric PVDF elements
has proven to be problematic, amongst others, due to the lack of
industrially-scalable methods to process PVDF into the appropriate polar
crystalline forms. Here, we show that fully piezoelectric PVDF films can be
produced via a single-step process that exploits the fact that PVDF can be
molded at temperatures below its melting temperature, i.e. via
solid-state-processing. We demonstrate that we thereby produce d_PVDF, the
piezoelectric charge coefficient of which is comparable to that of biaxially
stretched d_PVDF. We expect that the simplicity and scalability of solid-state
processing combined with the excellent piezoelectric properties of our PVDF
structures will provide new opportunities for this commodity polymer and will
open a range of possibilities for future, large-scale, industrial production of
plastic piezoelectric films
