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首页> 外文期刊>RSC Advances >Exploring the hydrated microstructure and molecular mobility in blend polyelectrolyte membranes by quantum mechanics and molecular dynamics simulations
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Exploring the hydrated microstructure and molecular mobility in blend polyelectrolyte membranes by quantum mechanics and molecular dynamics simulations

机译：用量子力学和分子动力学模拟探索共混聚电解质膜中水合微观结构和分子迁移率

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摘要

Quantum mechanics and molecular dynamics simulations were employed to examine several structural and dynamical characteristics in blend SPEEK-SPPO based membranes at varied water content and temperature values. QM results showed that water molecules were localized around the SPEEK and SPPO sulfonate groups due to the hydrogen bonding interactions, which caused proton dissociation at the increased hydrations. By increasing the hydration level, more water molecules occupied the sulfonate fragments because of the improved sulfonate-water interactions, whereas the hydrogen bond interaction of sulfonate-hydronium ion was weakened, enabling the hydronium ions to be away from the sulfonate groups. Based on water cluster size distribution and structure factor evaluations, it seemed that by improving the water content, isolated smaller aqueous clusters appeared under lower hydration levels, which merged together to form larger clusters comprising almost all molecules. Diffusivities for water and hydronium ion were observed to be enhanced by an increase in water uptake, which were attributed to the fact that larger hydrophilic clusters across the swollen blend SPEEK-SPPO PEMs promoted molecular mobility. Similarly, enhancing operational temperature gave rise to an enhancement in the membrane transport dynamics. Finally, predicted water and hydronium ion diffusion coefficients were noted to be smaller in hydrated SPEEK-SPPO membrane as compared to Nafion under identical conditions, which was in agreement with the experimental results.
机译：采用量子力学和分子动力学模拟，在不同水含量和温度值下探测混合Speek-SPPO膜中的几种结构和动态特性。 QM结果表明，由于氢键相互作用，在Speek和Sppo磺酸盐组周围局部地定位了水分子，这导致质子解离在增加的水合。通过增加水合水平，由于改善的磺酸盐 - 水相互作用，更多的水分子占据磺酸盐片段，而磺酸盐 - 散氢离子的氢键相互作用削弱，使得散氢离子远离磺酸盐基团。基于水簇尺寸分布和结构因子评估，似乎通过改善水含量，在较低的水合水平下出现较低的较小的含水簇，其合并在一起以形成几乎所有分子的较大簇。观察到水和散氢离子的扩散性通过增加水吸收来增强，这归因于肿胀混合Sppo-SPPO PEM促进分子迁移率的较大亲水簇。类似地，增强操作温度产生了膜输送动力学的增强。最后，与相同条件下的Nafion相比，预测水和散水离子扩散系数在水合的Speek-Sppo膜中较小，这与实验结果一致。

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  • 来源
    《RSC Advances》 |2016年第42期|共10页
  • 作者

    Bahlakeh Ghasem; Hasani-Sadrabadi Mohammad Mahdi; Jacob Karl I.;

  • 作者单位

    Golestan Univ Dept Engn &

    Technol Aliabad Katool Iran;

    Georgia Inst Technol George W Woodruff Sch Mech Engn Parker H Petit Inst Bioengn &

    Biosci Atlanta GA 30332 USA;

    Georgia Inst Technol George W Woodruff Sch Mech Engn Parker H Petit Inst Bioengn &

    Biosci Atlanta GA 30332 USA;

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  • 正文语种 eng
  • 中图分类 化学;
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