Enhancement of piezoelectricity in polymer PVDF based on molecular chain structure

In this paper, a novel polarization method was proposed, in which a partially isolated C=C double bond was constructed in the PVDF molecular chain by designing a step-by-step polarization process. The dielectric and piezoelectric properties of PVDF films were studied. The results show that the piezoelectric coefficient d33 is significantly improved. Specifically, the d33 increases from − 6.5 pC/N for traditional polarization to − 13.5 pC/N by 107%. The microstructures were investigated by Fourier transform infrared spectroscopy and X-ray Photoelectron Spectroscopy, and it is confirmed that the dehydrogenation defluorination reaction was effectively induced by the polarization method, and the C=C double bond is constructed. It is also observed that the introduction of C=C bond increases the content of polar β phase, and consequently its piezoelectric properties of PVDF films. This method improves the piezoelectric performance while maintaining the original excellent performance, and further broadens the application scenarios of PVDF.