Fluorinated polyethylene propylene (FEP) bipolar ferroelectret films with a specifically designed concentric tunnel structure were prepared by means of rigid-template based thermoplastic molding and contact polarization. The properties of the fabricated films, including the piezoelectric response, mechanical property, and thermal stability, were characterized, and two kinds of energy harvesters based on such ferroelectret films, working in 33- and 31-modes respectively, were investigated. The results show that the FEP films exhibit significant longitudinal and radial piezoelectric activities, as well as superior thermal stability. A quasi-static piezoelectric d₃₃ coefficient of up to 5300 pC/N was achieved for the FEP films, and a radial piezoelectric sensitivity of 40,000 pC/N was obtained in a circular film sample with a diameter of 30 mm. Such films were thermally stable at 120 °C after a reduction of 35%. Two types of vibrational energy harvesters working in 33-mode and 31-mode were subsequently designed. The results show that a power output of up to 1 mW was achieved in an energy harvester working in 33-mode at a resonance frequency of 210 Hz, referring to a seismic mass of 33.4 g and an acceleration of 1 g (g is the gravity of the earth). For a device working in 31-mode, a power output of 15 μW was obtained at a relatively low resonance frequency of 26 Hz and a light seismic mass of 1.9 g. Therefore, such concentric tunnel FEP ferroelectric films provide flexible options for designing vibrational energy harvesters working either in 33-mode or 31-mode to adapt to application environments.

中文翻译：

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具有充气同心隧道结构的氟化聚乙烯丙烯铁电驻极体：制备，表征和在能量收集中的应用

通过基于刚性模板的热塑性模塑和接触极化，制备了具有特殊设计的同心隧道结构的氟化聚乙烯丙烯（FEP）双极铁电驻极体薄膜。表征了所制备膜的性能，包括压电响应，机械性能和热稳定性，并研究了两种基于此类铁电驻极体膜的能量收集器，分别以33和31模式工作。结果表明，FEP膜表现出明显的纵向和径向压电活性，以及​​优异的热稳定性。准静态压电d ₃₃FEP薄膜的最大系数达到5300 pC / N，在直径为30 mm的圆形薄膜样品中，径向压电灵敏度为40,000 pC / N。降低35％后，此类薄膜在120°C时具有热稳定性。随后设计了两种以33模式和31模式工作的振动能量收集器。结果表明，在共振频率为210 Hz的33模式下工作的能量采集器中，参考地震质量33.4 g和加速度1 g（g是地球的重力）。对于以31模式工作的设备，在相对较低的26 Hz共振频率和1.9 g的轻地震质量下获得了15μW的功率输出。因此，这种同心隧道FEP铁电薄膜为设计以33模式或31模式工作的振动能量收集器提供了灵活的选择，以适应应用环境。