Exclusive self-aligned β-phase PVDF films with abnormal piezoelectric coefficient prepared via phase inversion.

Self-polarised poly(vinylidene fluoride), (PVDF), films were prepared via a facile phase-inversion technique wherein the polymorphism of the films was controlled from exclusive α- (>90%) to β-phase (>98%) by simply varying the quenching temperature from 100 °C to -20 °C, respectively. At low temperatures, the β-phase crystallites were found to be self-aligned, with the PVDF thin films possessing a high piezoelectric coefficient of up to -49.6 pm V(-1). The extraordinarily high β-phase and piezoelectric coefficient of these PVDF films make them suitable for electroactive and energy harvesting applications.