Flexible 1-3 Piezoelectric Composites with Soft Embedded Conductive Interconnects for Underwater Acoustic Transducers

Abstract

1-3 Piezoelectric composites have been widely used in underwater acoustic transducers because of their advanced electromechanical coupling properties relative to bulk piezoelectric ceramics. However, the existing applied composites are mainly rigid 1-3 PZT–epoxy resin composites, which have rigid structures and cannot be adapted to various sonar carriers with complex surfaces. Here, we design and develop a flexible 1-3 PZT–silicone rubber composite (PSC) for the first time. PSC combines a soft silicone rubber polymer in PZT with flexible embedded island-bridge conductive interconnects to enable the flexibility of both the piezoelectric sensing core and the electrical layer. The flexible wide bridge structure embedded in the polymer can cope with the large bending deformation of PSC with good conductive property, while the rigid thin island structure ensures the high acoustic performance of piezoelectric materials. A PSC sample is prepared with its structural parameters optimized via finite element analysis and is experimentally verified to have good flexibility, high electromechanical coupling coefficient ( k t = 0.7), great thermal stability (from 25 to 105 °C), and bending stability (bending angle up to 215°). In addition, a preparation method for flexible 1-3 PSC is introduced, which has the advantages of high efficiency, low cost, no sample size restriction, and no high-temperature operation. The flexible 1-3 PSC in this work paves an important way for the development and application of the next generation of flexible underwater acoustic transducers.