聚吡咯改性钛酸钡纳米颗粒/聚偏氟乙烯复合压电薄膜的制备及性能分析

Preparation of polypyrrole-modified barium titanate nanoparticles/polyvinylidene fluoride composite piezoelectric films and their performance analysis

为解决钛酸钡(BT)/聚偏氟乙烯(PVDF)复合材料中两相材料间介电差异较大和BT难极化的问题,先以吡咯(Py)为聚合单体,通过细乳液聚合法制备聚吡咯改性BT(记作BT@PPy)纳米颗粒,然后将此作为纺丝液组分,利用静电纺丝法构筑BT@PPy/PVDF复合压电薄膜;进一步将铜箔电极贴于复合压电薄膜上下表面,制备BT@PPy/PVDF压电纳米发电机。采用FT-IR、TEM和XRD等手段分析BT@PPy纳米颗粒的结构和形貌,测试复合压电薄膜的压电常数和压电纳米发电机的输出电压。结果表明:PPy成功包覆BT纳米颗粒,形成核壳结构;添加质量分数为1%的BT@PPy纳米颗粒填料,静电纺丝所得复合压电薄膜的剩余极化由未改性前的0.125μC/cm^(2)提升至0.472μC/cm^(2),压电常数从12 pC/N增加到23.2 pC/N;所制纳米发电机输出电压从0.2 V提升到2.5 V,对外部压力感知敏感。聚吡咯对BT纳米颗粒的改性,提升了BT/PVDF复合压电层中BT的极化程度和压电层的压电常数,从而提高了所制压电纳米发电机的输出电压。研究结果可为制备高压电输出的压电纳米发电机提供有益参考。

In order to solve the problems of big dielectric difference between barium titanate(BT)and polyvinylidene fluoride(PVDF)in BT/PVDF composites and the difficulty of polarization of BT,polypyrrole-modified BT nanoparticles(BT@PPy)were prepared via microemulsion polymerization by using pyrrole(Py)as polymeric monomer,and then the BT@PPy nanoparticles as spinning solution components for preparing BT@PPy/PVDF composite piezoelectric films by electrospinning method;then the BT@PPy/PVDF piezoelectric nanogenerator was prepared by attaching copper film electrode to the upper and lower surface of the composite piezoelectric film.The structure and morphology of BT@PPy nanoparticles were characterized by FT-IR,TEM and XRD.The piezoelectric constants of the composite films and the output voltage of the piezoelectric nanogenerator were measured.The results showed that polypyrrole successfully coated BT nanoparticles and formed a core-shell structure;when the mass fraction of BT@PPy nanoparticle filler was 1%,the residual polarization of the composite piezoelectric film increased from 0.125μC/cm^(2) before modification to 0.472μC/cm^(2),and the piezoelectric constant increased from 12 pC/N to 23.2 pC/N.The output voltage of the nano-generator was increased from 0.2 V to 2.5 V,and the nano-generator had good sensitivity to sense external pressure.The polypyrrole modification of BT nanoparticles could improve the polarization degree of BT in the BT/PVDF composite piezoelectric layer and the piezoelectric constant of the piezoelectric layer,so as to increase the output voltage of the piezoelectric generator.The study results provide useful reference for the preparation of piezoelectric nanogenerators with high piezoelectric output.