Polyvinylidene fluoride/lead zirconate titanate (PVDF/PZT) composite films have been prepared by direct ink writing and the effect of PZT content on crystallization behavior and electrical properties of film were systematically investigated. The composite films were characterized by scanning electron microscope (SEM), X-ray diffractometer (XRD), Flourier transform infrared spectroscope (FTIR) and differential scanning calorimeter (DSC). The results show that, surface modified PZT powder (PZT@PDA) is successfully coated by polydopamine (PDA), resulting in a large number of polar groups that interact with the —CF 2 — groups in PVDF, inducing the generation of polar β phase due to hydrogen bonding formed in the interaction. The β phase content in composite film increases with increasing PZT@PDA content, up to 28.09% as with 5 wt.% PZT@PDA. PZT@PDA plays a role of nucleating agent to promote the generation of polar phases in the film and also acts as an impurity hindering the growth of nuclei to reduce crystallinity. Moreover, the presence of PZT@PDA in interfaces provides more sites for the occurrence of interfacial polarization and thus improving the electrical properties of films. The composite film with 5 wt.% PZT@PDA possesses the highest dielectric constant (8.61) and residual polarization value (0.6803 µC/cm 2 ).
Flexible wearable sensing devices are in great demand for self-powered systems. In this study, we fabricated fiber films of poly(vinylidene fluoride) (PVDF) matrix embedded with modified lead zirconate titanate nanoparticles (PZT NPs) using the electrospinning process. Each fiber film was cut into small pieces of 2 × 2 cm 2 , and pairs of pieces were pressed with a hot-pressing method. Modified PZT NPs with a high piezoelectric coefficient were embedded in PVDF fibers as a piezoelectric-reinforcing phase, which promoted the formation of the polar β phase in PVDF. The embedded PZT NPs affected the distribution of the polarized electric field and formed a local electric field between two PZT NPs, which promoted the polarization of PVDF, thereby enhancing the piezoelectric properties of PVDF/PZT NPs fiber films. The piezoelectric coefficient ( d 33 ) of the PVDF/PZT NPs fiber films embedding 4 wt.% PZT NPs showed the most significant enhancement, from 12 pC/N for neat PVDF to 21 pC/N, which is an approximately 75% improvement. The results of this work demonstrate the great potential application of piezoelectric composite fiber films in flexible wearable sensing devices.
危险品化学品经营许可证（带存储）