Adhesive-free dual layer piezoelectric PVDF copolymer transducers in sender and receiver sequences

Adhesive free dual-layer ultrasonic transducers have been produced using a layer-by-layer deposition method. The proposed method deposits P(VDF-TrFE) copolymer from the fluid phase with intermediate electrodes on top of a PEI substrate. The processed transducers were characterized using a LCR analyzer, a pulse-echo experimental setup, and a numerical FEM model. The ultrasonic signals and frequency spectra from the different characterization methods were compared. By using one of transducer layers as a sender and the other as a receiver with an intermediate grounded electrode, the capacitive coupling between the layers was reduced significantly.