The effect of humidity on the ionic transport in the amorphous phase of poly(ethylene oxide) thin films has been studied by local dielectric spectroscopy. We explored a controlled humidity range between 15% RH and 50% RH. AFM-based local dielectric imaging allowed the thin film topography and the corresponding dielectric contrast maps to be obtained simultaneously. No humidity effect on the film topography was observed whereas large variation of the dielectric signal could be detected. In addition, we observed a clear dielectric contrast in different locations on the thin film surface. At selected regions with high contrast in the dielectric maps, we performed nanoDielectric Spectroscopy (nDS) measurements covering the frequency range from 5 Hz to 100 kHz. By modeling these spectroscopy results, we quantified the conductivity of the amorphous phase of the semicrystalline poly(ethylene oxide) films. The crystalline fraction of the PEO thin films was extracted and found to be about 36%, independently of humidity. However, the average conductivity increased by a factor of 25 from 2 × 10⁻¹⁰ to 5 × 10⁻⁹ S cm⁻¹, by changing environmental humidity in the explored % RH range.

中文翻译：

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通过局部介电谱研究环境湿度对聚环氧乙烷薄膜离子迁移的影响

通过局部介电谱研究了湿度对聚环氧乙烷薄膜非晶相中离子迁移的影响。我们探索了在15％RH和50％RH之间的受控湿度范围。基于AFM的局部介电成像可同时获取薄膜形貌和相应的介电对比图。没有观察到湿度对膜形貌的影响，而可以检测到介电信号的较大变化。此外，我们在薄膜表面的不同位置观察到了清晰的介电对比。在介电图中具有高对比度的选定区域，我们进行了纳米介电谱（nDS）测量，覆盖了从5 Hz到100 kHz的频率范围。通过对这些光谱结果进行建模，我们量化了半结晶聚环氧乙烷薄膜非晶相的电导率。提取PEO薄膜的结晶分数，发现其为约36％，与湿度无关。但是，平均电导率从2×10增加了25倍^-10至5×10 ^-9 S cm ^-1，方法是在探索的RH百分比范围内改变环境湿度。