Giant Piezoelectric Coefficient of Polyvinylidene Fluoride with Rationally Engineered Ultrafine Domains Achieved by Rapid Freezing Processing.

Domains play an essential role in determining the piezoelectric properties of polymers. The conventional method for achieving ultrafine piezoelectric domain structures for polymers is multiphase polymerization, which is not the primary choice for industrial-scale applications because of its complex synthesis and weak mechanical properties. In this study, it is demonstrated for the first time that a nanoscale domain design can be achieved in a commercially available polyvinylidene fluoride (PVDF) homopolymer through a simple fabrication method involving cyclic compression and rapid freezing. The domain-engineered PVDF exhibits largely enhanced piezoelectric output with a record-breaking piezoelectric coefficient (d) of 191.4 picocoulombs per Newton (8.9 times higher than that of PVDF without engineered domain structure) and electromechanical coupling factor (k) of 77.1%. Moreover, nanoscale domain-induced ferroelectric and dielectric evolutions are revealed. A smaller domain is found to be beneficial for domain switching. An in-depth understanding of the interplay between the domain structure and piezoelectric properties reveals a simple, low-cost method for fabricating high-performance polymeric piezoelectric.