Flexible 1-3 Composite Ultrasound Transducers With Silver-Nanowire-Based Stretchable Electrodes

In this article, a flexible piezo-composite transducer composed of the active piezoelectric material (PZT-5H) and passive polymer matrix [polydimethylsiloxane (PDMS)] is developed to achieve excellent flexibility, sensitivity, and bandwidth for biomedical and industrial applications. The flexible electrodes [silver nanowires (AgNWs) mixed with PDMS] are deposited on the transducers using a spray coating method, providing a sufficient conductivity of an electrode through repeated bending tests. The flexible 1-3 composite transducer exhibits robust mechanical flexibility (curved radius <5 mm) without failure due to the stretchable mechanical properties of PDMS and AgNWs network, which indicates that the AgNW/PDMS electrode is a promising alternative to conventional metal-type electrodes, such as Au film. The acoustic characterization suggests that the -6 dB fractional bandwidth (similar to 49%) and transmitting sensitivity (similar to 107 mV/V) of the prototyped transducer are promising for nondestructive testing, biomedical imaging, and therapy.