基于ULVI技术的PVDF隔膜显微结构表征研究

Research on Microstructure Characterization for PVDF Diaphragm Based on Ultra Low Voltage Imaging (ULVI) Technology

PVDF隔膜为绝缘高分子材料,在扫描电镜观察时易产生放电问题,降低了成像图片的分辨率与清晰度,使得到的电子图像不能反映样品表面的真实形貌。通过DSC图谱分析其热稳定性,采用低加速电压成像技术,对扫描电子显微镜的工作电压(Vacc)、工作电流(le)、工作距离(WD)、扫描方式及电子信号这5个参数进行优化调整,最终选择在工作电流为5 μA,工作电压为1.5 kv,工作距离为4.5 mm,扫描方式为快速扫描,采用背散射电子信号进行成像的工艺,利用这种分析工艺能更好的表征出PVDF复合隔膜表面微观形貌及断面微观形貌。

Discharge problem was produced by using the scanning electron microscopy (SEM) to observe the PVDF diaphragm. The resolution and sharpness of the image are reduced, so the electronic image cannot reflect the real appearance of the sample surface. Its thermal stability is analyzed through the DSC pattern and then by using Ultra low voltage imaging (ULVI) technology to optimize and adjust five parameters of SEM: Vacc, launching electricity (le), working distance (WD), scanning mode and electronic signal. Finally, 5 μA launching electricity, 1.5 kv Vacc, 4.5 mm working distance and rapid scanning were selected. In LA-High mode with backscatter electronic signal was adopted. The surface morphology of PVDF composite diaphragm and the surface morphology of cross section can be characterized by this analysis process.