Nafion composite membranes with various amounts of sulfonated multi-walled carbon nanotubes (Su-CNTs) were prepared either in or without a strong magnetic field. Interestingly, it is found that being recast in a strong magnetic field, the tensile strength at break and proton conductivity of Su-CNTs/Nafion composite membranes parallel to the magnetic field direction were higher than those perpendicular to magnetic field. Remarkably, such anisotropic mechanical property and proton conductivity of Su-CNTs/Nafion composite membranes strongly depend on water uptake and temperature, in particular the content of Su-CNTs. Quite a different dependence of the proton conductivity of the composite membranes on Su-CNT content, relative humidities and temperatures is well explained for the anisotropic proton conductivity of the Su-CNTs/Nafion membrane recast in a strong magnetic field, which is attributed to the preferential proton transporting along ionic water channels mainly coalesced by the orientated Su-CNTs at a specific water uptake. For Nafion composite membranes with 5 wt.% Su-CNTs, the proton conductivity along the direction of treating magnetic field approaches to 0.216 S/cm, which is ∼\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\sim$$\end{document} 46% higher than that perpendicular to the magnetic field at 95 ∘\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$^{\circ }$$\end{document}C. The present work provides a deep insight of the humidity and temperature dependence of proton conductivity of Su-CNTs/Nafion composite membranes and a new strategy for fabrication proton exchange membranes with high proton conductivity as well as good mechanical property.

中文翻译：

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具有各向异性机械和质子传导性能的磁性定向磺化碳纳米管/Nafion复合膜

在强磁场或无强磁场中制备了具有不同量磺化多壁碳纳米管 (Su-CNT) 的 Nafion 复合膜。有趣的是，发现在强磁场中重铸，平行于磁场方向的 Su-CNTs/Nafion 复合膜的断裂拉伸强度和质子传导率高于垂直于磁场方向的膜。值得注意的是，Su-CNTs/Nafion 复合膜的这种各向异性机械性能和质子传导性强烈依赖于吸水率和温度，尤其是 Su-CNTs 的含量。复合膜的质子电导率对 Su-CNT 含量的依赖性完全不同，相对湿度和温度很好地解释了在强磁场中重铸的 Su-CNTs/Nafion 膜的各向异性质子电导率，这归因于沿着离子水通道的优先质子传输，主要由定向的 Su-CNTs 在特定位置聚结吸水。对于含有 5 wt.% Su-CNTs 的 Nafion 复合膜，沿处理磁场方向的质子电导率接近 0.216 S/cm，这是∼\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\ oddsidemargin}{-69pt} \begin{document}$$\sim$$\end{document} 比垂直于 95 度的磁场高 46% ∘\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage {wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$^{\circ } $$\end{文档}C. 目前的工作提供了对 Su-CNTs/Nafion 复合膜质子电导率的湿度和温度依赖性的深入了解，以及制造具有高质子电导率和良好机械性能的质子交换膜的新策略。