强电场作用下BiCl_3/PVDF膜的制备与其压电性能研究

Preparation and piezoelectric properties of BiCl_3/PVDF films under strong electric field

为了得到压电转换效率高的PVDF压电膜,提高PVDF薄膜中的β晶含量以及控制薄膜的微结构是关键。以BiCl_3/PVDF混合溶液在强电场中流延成膜。通过FT-IR,XRD与SEM表征了复合膜的晶相组成与微结构特征,将复合膜组装成压电器件并测试了其压电响应。结果表明,BiCl_3与强电场分别对复合膜的晶相组成与排列有较大的影响,BiCl_3掺杂量达到2%(质量分数)时,结晶度最大达到76.5%,β晶的含量最高达到89.5%。强电场促进了复合膜中β晶的形成与取向排布,进一步提高了复合膜的压电响应,相比于无电场下制得的复合膜,电场强度为750kV/m下制得的复合膜的输出电压提升了3倍,电压正峰值达到60.8V,其瞬时输出功率面密度达到120.1μW/cm^2,正常工作的最高冲击频率为250Hz。

In order to obtain a PVDF piezoelectric film with high piezoelectric conversion efficiency, it is critical to increase the β crystal content in the PVDF film and control the microstructure of the film. In this paper, a mixed solution of BiCl 3/PVDF was cast into a film in a strong electric field. The crystal phase composition and microstructure characteristics of the composite membrane were characterized by FT-IR, XRD and SEM. The composite membrane was assembled into a piezoelectric device and its piezoelectric response was tested. The results show that BiCl 3 and the strong electric field had a great influence on the microstructure and β crystal orientation in the composite film. When the concentration of BiCl 3 was 2wt%, the crystallinity reached 76.5% and the β crystal content reached 89.5% in the composite film. The strong electric field promoted the formation and orientation arrangement of β-crystal in the composite film. When it was cast in an electric field intensity of 750 kV/m, the BiCl 3/PVDF composite membrane was 60.8 V in piezoelectric response, 120.1 μW/cm 2 in instantaneous output power surface density and 250 Hz in the maximum shock frequency.