Korea Research Institute of Standards and Science, Daejeon, 34113, Republic of Korea.
School of Advanced Materials Science and Engineering, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea.
Small. 2022 Apr;18(17):e2105811. doi: 10.1002/smll.202105811. Epub 2022 Mar 1.
Electrospun polymeric piezoelectric fibers have a considerable potential for shape-adaptive mechanical energy harvesting and self-powered sensing in biomedical, wearable, and industrial applications. However, their unsatisfactory piezoelectric performance remains an issue to be overcome. While strategies for increasing the crystallinity of electroactive β phases have thus far been the major focus in realizing enhanced piezoelectric performance, tailoring the fiber morphology can also be a promising alternative. Herein, a design strategy that combines the nonsolvent-induced phase separation of a polymer/solvent/water ternary system and electrospinning for fabricating piezoelectric poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE) fibers with surface porosity under ambient humidity is presented. Notably, electrospun P(VDF-TrFE) fibers with higher surface porosity outperform their smooth-surfaced counterparts with a higher β phase content in terms of output voltage and power generation. Theoretical and numerical studies also underpin the contribution of the structural porosity to the harvesting performance, which is attributable to local stress concentration and reduced dielectric constant due to the air in the pores. This porous fiber design can broaden the application prospects of shape-adaptive energy harvesting and self-powered sensing based on piezoelectric polymer fibers with enhanced voltage and power performance, as successfully demonstrated in this work by developing a communication system based on self-powered motion sensing.
电纺聚合物压电纤维在生物医学、可穿戴和工业应用中的自适应机械能量收集和自供电传感方面具有很大的潜力。然而，它们不尽如人意的压电性能仍然是一个需要克服的问题。虽然提高电活性β相结晶度的策略一直是实现增强压电性能的主要关注点，但纤维形态的调整也可能是一种很有前途的替代方法。在此，提出了一种设计策略，将聚合物/溶剂/水三元体系的非溶剂诱导相分离与静电纺丝相结合，在环境湿度下制备具有表面多孔结构的压电聚偏氟乙烯-三氟乙烯（P(VDF-TrFE)）纤维。值得注意的是，在输出电压和发电方面，具有更高表面多孔性的电纺 P(VDF-TrFE)纤维优于具有更高β相含量的光滑表面纤维。理论和数值研究也支持结构多孔性对收集性能的贡献，这归因于由于孔隙中的空气导致的局部应力集中和介电常数降低。这种多孔纤维设计可以拓宽基于压电聚合物纤维的自适应能量收集和自供电传感的应用前景，提高电压和功率性能，如本工作通过基于自供电运动传感的通信系统的开发所证明的那样。
