Effect of polymer electrode thickness on the acoustical properties of all-screen printed piezoelectric PVDF copolymer transducers

High frequency poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] copolymer ultrasonic transducers were prepared by screen printing as an all-printed device with conductive poly(3,4-ethylenedioxythiophene): poly(styrene sulfonate) (PEDOT:PSS) used the electrode material. A large number of prototypes with different electrode areas and electrode thickness were obtained by printing single or dual layers of the conductive polymer. The printed transducers were characterized using impedance and acoustic backscattering measurements. Effects imposed by the PEDOT: PSS conductivity were also evaluated both through experiments and finite element method (FEM) modeling, pointing out important limitations of conductive polymers when applied in high frequency ultrasonic transducers. (C) 2014 The Japan Society of Applied Physics