Dome-like PVDF actuators: Preparation, phase transformation and piezoelectric properties

In this work, dome structures in PVDF films were prepared as ultrasonic transducer. The domes are realized by a deep drawing process. The dome-forming process leads to a phase transformation from the non-polar alpha into the polar beta phase within dome wall and roof of the PVDF films. A ferroelectric polarization is obtained in these dome areas after suitable electrical poling which yields a piezoelectric activity. Because of the piezoelectric activity within the film plane, a dome-roof up-and-down actuation is observed with resonance frequencies in the range between 65 and 93 kHz.