AbstractThe influence of the semialiphatic backbone on molecular ordering and proton conductivity was investigated in comparison to the rigid aromatic backbone in highly proton-conductive organized polyimide thin films. We newly synthesized two alkyl-sulfonated semialiphatic polyimides (ASSPIs) with different molecular weights and investigated their molecular organized structure, proton conductivity, water uptake, and the dissociation state of protons from sulfonic acid groups in thin films by in situ measurements for grazing incidence small-angle X-ray scattering (GISAXS), quartz crystal microbalance (QCM), fourier transform infrared (FT-IR) spectra, and impedance spectra. Declining planarity in the semialiphatic backbone reduced the aggregative character and molecular ordering in the lyotropic liquid-crystalline (LC) structure. However, the higher-molecular-weight ASSPI exhibited the oriented lamellar structure despite the lower planarity of the main chain. The proton conductivity of the oriented lamellar thin film had more than half an order of magnitude higher value of 1.5 × 10-1 S cm-1 than did the nonoriented lamellar thin film (3.0 × 10-2 S cm-1) at 25 °C and 95% RH. These results indicate that in sulfonated polyimide thin films, the lamellar orientation greatly contributes to the high proton conductivity in ASSPI thin films.High-molecular-weight (HMw) sulfonated polyimide thin films with a semialiphatic main chain exhibited an oriented lamellar structure and high proton conductivity (1.5 × 10-1 S cm-1) under humidified conditions. Low-molecular-weight (LMw) sulfonated polyimide thin films with the same semialiphatic backbone exhibited a nonoriented lamellar structure and low proton conductivity (3.0 × 10-2 S cm-1) under humidified conditions. The results indicate that, in sulfonated polyimide thin films with semialiphatic main chain, the lamellar orientation greatly contributes to the high proton conductivity.

中文翻译：

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磺化半脂肪族聚酰亚胺薄膜中高质子传导性的溶致排序

摘要 与高质子传导有组织的聚酰亚胺薄膜中的刚性芳族主链相比，研究了半脂族主链对分子排序和质子传导性的影响。我们新合成了两种不同分子量的烷基磺化半脂肪族聚酰亚胺 (ASSPI)，并通过原位测量，研究了它们的分子组织结构、质子电导率、吸水率以及薄膜中磺酸基团质子的解离状态。角 X 射线散射 (GISAXS)、石英晶体微量天平 (QCM)、傅立叶变换红外 (FT-IR) 光谱和阻抗光谱。半脂肪族主链中平面度的下降降低了溶致液晶 (LC) 结构中的聚集特性和分子排序。然而，尽管主链的平面度较低，但较高分子量的 ASSPI 表现出定向的层状结构。取向层状薄膜的质子传导率在 1.5 × 10-1 S cm-1 比非取向层状薄膜（3.0 × 10-2 S cm-1）高半个数量级，在 25 ° C 和 95% RH。这些结果表明，在磺化聚酰亚胺薄膜中，层状取向极大地促进了 ASSPI 薄膜的高质子传导性。 具有半脂肪族主链的高分子量 (HMw) 磺化聚酰亚胺薄膜表现出取向层状结构和高质子加湿条件下的电导率 (1.5 × 10-1 S cm-1)。具有相同半脂肪族主链的低分子量 (LMw) 磺化聚酰亚胺薄膜在加湿条件下表现出非取向层状结构和低质子传导率 (3.0 × 10-2 S cm-1)。结果表明，在具有半脂肪族主链的磺化聚酰亚胺薄膜中，层状取向极大地有助于高质子传导性。