Piezoelectric polymers hold great promise in flexible electromechanical conversion devices. The conventional view is that the piezoelectric phase of these polymers is dominated by a polar crystal phase. Guided by this understanding, enormous effort has been dedicated to enhancing piezoelectric performance via mediating the proportion or orientation of polar crystal. However, theoretical and experimental results indicate that the piezoelectric response of a pure polymer cannot be doubled, and the piezoelectric constant (|d|) can hardly reach 60 pm/V, greatly hindering the future progress of piezoelectric polymers. Recent evidence suggests that the structure distortions within the polar crystal phase as well as the paracrystal between the polar crystal and amorphous fraction are closely connected with piezoelectricity. With this new understanding, pure polymers with a giant piezoelectric response (featuring a |d| above 60 pm/V) can be readily achieved. Numerous recent studies have demonstrated the great potential of this new understanding in obtaining high-performance piezoelectric polymers. Herein, this review highlights the newly discovered piezoelectric phase structures, including structure distortion (within polar crystal) and interphase paracrystal, via analyzing the structure features and their piezoelectric contributions. Inspired by the newly evolved phase structure, the possibility of obtaining a giant piezoelectric response is expected in renewable and biodegradable piezoelectric polymers due to the similar phase configuration. Furthermore, possible theoretical developments, including new insight into the giant piezoelectric response and the dynamics at piezoelectric polymer/liquid interface are discussed. The feasibility and great promise of these developments have been demonstrated via the emerging applications in piezoelectric sensor/nanogenerator/actuator, self-display sensing, air filtration, droplet hydraulic generator, solar interfacial vapor, battery with liquid electrolyte, water treatment and electrical stimulation therapy.

中文翻译：

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具有巨压电响应的纯聚合物的相结构破译


压电聚合物在柔性机电转换器件中具有广阔的前景。传统观点认为这些聚合物的压电相以极性晶相为主。在这种理解的指导下，人们付出了巨大的努力来通过调节极性晶体的比例或方向来增强压电性能。然而理论和实验结果表明纯聚合物的压电响应无法加倍，压电常数（|d|）很难达到60 pm/V，极大地阻碍了压电聚合物的未来进步。最近的证据表明，极性晶相内以及极性晶体和非晶部分之间的副晶内的结构畸变与压电性密切相关。有了这种新的认识，可以很容易地获得具有巨大压电响应（|d|高于 60 pm/V）的纯聚合物。最近的大量研究证明了这种新认识在获得高性能压电聚合物方面的巨大潜力。本文通过分析结构特征及其压电贡献，重点介绍了新发现的压电相结构，包括结构畸变（极性晶体内）和相间副晶。受新进化的相结构的启发，由于相似的相配置，预计可再生和可生物降解的压电聚合物有可能获得巨大的压电响应。此外，还讨论了可能的理论发展，包括对巨压电响应和压电聚合物/液体界面动力学的新见解。 这些发展的可行性和巨大前景已通过压电传感器/纳米发电机/执行器、自显示传感、空气过滤、液滴水力发电机、太阳能界面蒸汽、液体电解质电池、水处理和电刺激疗法等新兴应用得到证明。 。