The role of fluoropolymer physicochemical properties in the dynamic evolution of nanostructure and ionic conductivity in perfluorinated sulfonic acid ionomer thin films was investigated by in situ water sorption experiments. The properties and mass fraction of the ionomer matrix were systematically varied between Nafion and a perfluorodioxolane ionomer with the same sulfonic acid side chain and mass fractions ranging from 0.26 to 0.57. Swelling rate constants attributed to Fickian mass transport (∼10^–2 s^–1) decreased with increasing ionic strength and humidity (i.e., with increased swelling) while rate constants associated with morphological rearrangement (∼10^–3 s^–1) increased. The rate of deformation, in nm s^–1, was primarily dictated by the matrix segmental mobility. Transient hydration-driven conductivity exhibited a single rate constant (∼10^–3 s^–1) corresponding to the morphological process. In situ grazing incidence X-ray scattering experiments reveal a rapid formation of ionomer domains during Fickian water sorption, followed by a slower ordering of these domains during hydration. This relationship between the rates of swelling and morphological changes confirm/pinpoint transient changes controlling ion conduction mechanisms in ionomer thin films.

中文翻译：

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全氟磺酸离聚物的纳米结构和传输性质的动态出现。

通过原位水吸附实验研究了含氟聚合物理化性质在全氟化磺酸离聚物薄膜中纳米结构和离子电导率的动态演变中的作用。在Nafion和具有相同磺酸侧链的全氟二氧戊环离聚物之间，离聚物基质的性质和质量分数在系统上有所不同，质量分数在0.26至0.57范围内。随着离子强度和湿度（即溶胀增加）的增加，归因于菲克质量迁移的溶胀速率常数（〜10 ^–2 s ^–1）降低，而与形态重排相关的溶胀速率常数（〜10 ^–3 s ^–1）） 增加。变形速率（以nm s ^–1为单位）主要由基质分段迁移率决定。瞬态水合驱动的电导率表现出与形态学过程相对应的单一速率常数（〜10 ^–3 s ^–1）。原位放牧入射X射线散射实验表明，在Fickian吸水过程中，离聚物域快速形成，随后在水化过程中，这些域的排列较慢。溶胀速率和形态变化之间的这种关系证实/精确控制了离聚物薄膜中离子传导机理的瞬态变化。