Enhanced Temperature Stability of Piezoelectricity in Polymeric Blends via Configuration Confinement Effect

Temperature-stable piezoelectricity of dielectric polymers is demanded for accurate vibration sensing applications, but the thermal activated molecular motion could disrupt the polarization switching of electroactive crystalline regions, which precludes their applications in a wider temperature range. Here a general material design strategy to enhance the temperature stability of piezoelectric response is reported by blending a piezoelectric polymer and a high glass-transition temperature polymer as a binary polymeric blend to induce confinement effect on thermal configuration change. The improved thermal stability stems from the confinement effect of the homogenously distributed binary, which is evidenced by the single glass transition behavior revealed by dynamic mechanical analysis and the temperature-insensitive long period of the blends from small-angle X-ray scattering results. Therefore, the blends display a steady piezoelectric coefficient d33 of about 11.0~14.1 pC/N ranging from 25°C to 55°C, outperforming its pristine polymers. Ultrasonic sensor prototypes were fabricated with the developed materials and ultrasonic sensing evaluation at the frequency of 20 kHz, 100 kHz and 200 kHz were successfully monitored, illustrating the potential application of the piezoelectric blends. Our findings provide a general strategy to attain temperature-stable high-piezoelectricity polymers for vibration sensing applications.