Fabrication of poly (vinylidene fluoride) films by ultrasonic spray coating; uniformity and piezoelectric properties

•Ultrasonic spray coating system is used for fabrication of pure PVDF films with high piezoelectric coefficient (d33 = 48 pm/V).•Highly crystalline (56%) PVDF films with predominant β phase for flexible and transparent engineering devices are achieved without post processing.•Uniformity and roughness (<50 nm) of the PVDF films strongly affects their piezoelectric properties.•We proved that the ultrasonic spray coating method is capable of producing large-scale, low-cost PVDF films in a single step.