In this study, the influence of polymer water content on ion diffusion coefficients of alkali metal chlorides (LiCl, NaCl, and KCl) in cross-linked poly(ethylene glycol) diacrylate (XLPEGDA) hydrogels was investigated. This research is part of a broader effort to understand the fundamentals of water and ion transport in hydrated polymers. Salt diffusion coefficients were calculated from salt permeability and sorption measurements. XLPEGDA hydrogels were synthesized with three different water contents (50, 70, and 90 g water/g dry polymer). The diffusion coefficients of alkali metal chlorides in XLPEGDA polymers increased as water content increased. The Mackie and Meares model, which accounts for polymer chain obstruction (i.e., tortuosity) effects on salt diffusion in hydrated polymers, was used to interpret salt diffusion coefficients. The general trend of the experimentally determined salt diffusion coefficients in these polymers is consistent with the model. Individual ion diffusion coefficients in the samples were obtained by combining salt permeability/sorption data with ionic conductivity results. The chloride ion diffusion coefficients were similar for all salts. The relative order of alkali metal ion diffusion coefficients in these polymers was different from that in aqueous solution (i.e., $D_{K^{+}}^s>D_{N{a}^{+}}^s>D_{L{i}^{+}}^s$). Moreover, this order changes as polymer water content varies, suggesting that alkali metal chloride diffusion behavior in XLPEGDA polymers is influenced by both ion hydration and polymer-ion specific interactions.

在这项研究中，研究了聚合物水含量对交联聚乙二醇（二甘醇）二丙烯酸酯（XLPEGDA）水凝胶中碱金属氯化物（LiCl，NaCl和KCl）离子扩散系数的影响。这项研究是一项广泛工作的一部分，旨在了解水合聚合物中水和离子迁移的基本原理。盐的扩散系数由盐的渗透率和吸附量计算得出。合成了具有三种不同水含量（50、70和90克水/克干聚合物）的XLPEGDA水凝胶。随着水含量的增加，碱金属氯化物在XLPEGDA聚合物中的扩散系数增加。Mackie and Meares模型用来解释盐链在水合聚合物中扩散的聚合物链阻塞（即曲折）效应。这些聚合物中实验确定的盐扩散系数的总体趋势与该模型一致。通过将盐渗透性/吸附数据与离子电导率结果相结合，获得了样品中各个离子的扩散系数。所有盐的氯离子扩散系数均相似。这些聚合物中碱金属离子扩散系数的相对顺序不同于水溶液中的相对顺序（即，$d_{{ķ}^{+}}^s>d_{ñ{\mathrm{一种}}^{+}}^s>d_{\mathrm{大号}{\mathrm{一世}}^{+}}^s$）。此外，该顺序随聚合物水含量的变化而变化，表明XLPEGDA聚合物中碱金属氯化物的扩散行为受离子水合和聚合物-离子特异性相互作用的影响。