In-situ observation of an anion exchange membrane (AEM), QPAF-4, synthesized by the group of University of Yamanashi, was performed under various humidity conditions by synchrotron X-ray scattering measurements. The absorption process of water vapor into the AEM was slow, taking even a few hours. When the environmental humidity decreased, the amount of water contained in the membrane decreased also very slowly. Hysteresis was clearly observed during the absorption and desorption processes. Although the amount of absorbed water was very small, a meaningful difference in the X-ray scattering intensity was found between water-absorbed and dry membrane. The radial distribution functions (RDFs) of the membrane under various humidity conditions were obtained by subtracting the scattering of the chamber, where the humidity and the temperature were contorted from the scattering intensity from the membrane in the chamber. The peak at 2.8 Å was assigned to the hydrogen bonding interaction of O(water)-O(water) and non-hydrogen bonded interaction of water molecules. These peaks increased under a high humidity condition. In-situ observation in the present study clarified the humidity dependence of the bonding state of water in the AEM.

中文翻译：

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通过 X 射线散射对各种湿度下的阴离子交换膜进行原位观察


由山梨大学课题组合成的阴离子交换膜 （AEM） QPAF-4 在各种湿度条件下通过同步加速器 X 射线散射测量进行了原位观察。水蒸气吸收到 AEM 中的过程很慢，甚至需要几个小时。当环境湿度降低时，膜中所含的水量也下降得非常缓慢。在吸收和解吸过程中可以清楚地观察到滞后。尽管吸收的水量非常小，但发现吸水膜和干膜之间的 X 射线散射强度存在有意义的差异。通过减去腔室的散射来获得膜在各种湿度条件下的径向分布函数 （RDF），其中湿度和温度与腔室中膜的散射强度相扭曲。2.8 Å 处的峰被分配给 O（水）-O（水）的氢键相互作用和水分子的非氢键相互作用。这些峰值在高湿度条件下增加。本研究中的原位观察阐明了 AEM 中水键合态的湿度依赖性。