A molecular ferroelectrics induced electroactive -phase in solution processed PVDF films for flexible piezoelectric sensors

Piezoelectric polymers such as poly(vinylidene fluoride) (PVDF) have attracted great interest for applications in flexible sensors and wearable electronic devices. A high content of the electroactive -phase in PVDF is one of the prerequisites for achieving excellent piezoresponse and sensing. In this work, composite films with high content of the -phase in a PVDF matrix were prepared by blending a molecular ferroelectric with multiple polarization axes (dabcoHReO(4)) with PVDF. An obvious change from the -phase to the -phase in PVDF was achieved by exploring the hydrogen bonding interaction between the PVDF matrix and dabcoHReO(4) fillers and evidenced by the FT-IR and XRD results. We found that the -phase content in the composite materials depended on the content of dabcoHReO(4), in which 8 wt% of dabcoHReO(4) enabled induction and stabilization of the -phase content up to 95%. In addition, the composite films prepared by simple solution processes exhibited excellent ferroelectric and piezoelectric properties, evidenced by ferroelectric hysteresis loops and piezoelectric vibration tests. These results indicate that the dabcoHReO(4)-PVDF composite materials can be potentially used in flexible sensing electronics and next-generation electronics.