关键词: 聚多巴胺(PDA), 静电纺丝, 钛酸钡(BT), 聚偏氟乙烯(PVDF), 分散性, 压电薄膜, 压电纳米发电机

Abstract: With the improvement of people's living standards and quality of life, emerging industries and multidisciplinary fields such as the Internet of Things, big data and artificial intelligence are developing rapidly. Intelligent wearable devices begin to flood into the public life and get rapid development, and the demand for flexible and durable power is also increasing. As electronic devices consume less and less power, it is possible to convert environmental energy such as solar, thermal and mechanical energy into weak electricity to drive electronic devices. Therefore, piezoelectric nanogenerators have been widely studied as a power source for wearable electronic devices due to their advantages of large energy output, long service life, convenient manufacture and relatively stable output. At the same time, piezoelectric nanogenerators also have good flexibility and mechanical stability, which makes it possible for the development of fully flexible self-driven modern electronic equipment. The PVDF has excellent piezoelectric properties, the film made of PVDF is soft, light and deformable, and can be made into sensors of any shape and size. It can be closely combined with wearable products to realize the intellectualization of wearable products. PVDF-based piezoelectric nanogenerators have a promising development prospect in the field of wearable products. However, the low electromechanical coupling coefficient and piezoelectric coefficient d33 limit the application of piezoelectric polymers. In order to overcome the shortcomings, inorganic piezoelectric BT nanoparticles with high piezoelectric coefficient were blended with flexible PVDF, so that the BT nanoparticles were dispersed in the PVDF matrix. The piezoelectric properties of the composites are improved to some extent while the advantages of flexibility, light weight and easy processing are retained. However, the poor dispersion of BT nanoparticles in the PVDF matrix limits the piezoelectric properties of the composites. In order to solve the problem of uneven dispersion of BT nanoparticles in the PVDF matrix, the BT nanoparticles were modified with polydopamine to prepare polydopamine-modified BT nanoparticles (pBT). And pBT/PVDF composite piezoelectric films were prepared by electrospinning and the composite spinning solution of PVDF and pBT nanoparticles. The dispersion of BT nanoparticles in the PVDF matrix was improved, and the high voltage property of BT nanoparticles was fully brought into play. The results showed that the pBT nanoparticles with core-shell structure could be evenly dispersed in the PVDF matrix, and the agglomeration was significantly reduced. When the content of pBT nanoparticles was 3, the d33 of pBT/PVDF composite piezoelectric film increased from 13±3 pc/N before modification to 20±3 pc/N. The output voltage of pBT/PVDF piezoelectric nanogenerator could reach 1.2 V. This paper provides a simple modified method to successfully solve the problem of uneven dispersion of the BT nanoparticles in the PVDF matrix, and to significantly improve the output voltage of the pBT/PVDF piezoelectric nanogenerator. The pBT/PVDF piezoelectric nanogenerator has great application prospects in intelligent textiles, wearable electronic devices and other fields.

Key words: polydopamine, electrospinning, barium titanate, polyvinylidene fluoride, dispersibility, piezoelectric film, piezoelectric nanogenerator