Microstructured Electrode‐Piezopolymer Interface for Ultrasound Transducers With Enhanced Flexibility and Acoustic Performance

ABSTRACT Ultrasound transducers made from rigid piezoceramics are difficult to adapt for wearable or conformal applications. Piezopolymer‐based transducers offer a practical alternative; however, most existing studies focus on piezoelectric materials, while the influence of electrode material and electrode–polymer interface remains underexplored. This study leverages different interface‐engineering strategies to examine the influence of electrode–piezopolymer interface morphology on piezoelectric, dielectric, and acoustic behavior in flexible transducers. Devices were fabricated using silver (Ag), gold (Au), graphene flakes (GF), laser‐induced graphene (LIG), and Au‐decorated LIG electrodes, enabling comparison across interfacial architectures. LIG‐based transducers showed strong acoustic and piezoelectric output due to partial infiltration of the piezopolymer into the porous LIG network, which enhances interfacial contact and stress transfer. Au‐based transducers achieved comparable acoustic output. In contrast, dense Ag electrodes and layered GF films provided limited coupling, resulting in reduced electromechanical response. LIG‐based transducers exhibited the highest flexibility and durability, retaining stable performance after 10,000 bending cycles and an eight‐week aging study, whereas GF, Ag, and Au devices degraded under bending, and Ag electrodes declined over time. These findings demonstrate that engineering the electrode–polymer interface is critical for high‐performance flexible ultrasound transducers and identify LIG as a strong candidate for wearable imaging applications.