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首页> 外文会议>NMR spectroscopy of polymers: Innovative strategies for complex macromolecules >Understanding Anisotropy, Transport, and Ion Associations Inside Ionic Polymers
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Understanding Anisotropy, Transport, and Ion Associations Inside Ionic Polymers

机译：了解离子聚合物内部的各向异性，迁移和离子缔合

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摘要

Anisotropy, transport and ion associations critically determine the performance of many ionic polymer-based materials and devices, from fuel cells to batteries to ionic transducers. Our group is pursuing a range of NMR studies combined with other structural and morphological information to understand these complex materials. We observe uniformly aligned hydrophilic channels in different perfluorosulfonate ionomers and aromatic-based multi-block copolymers, quantified by ~2H NMR spectroscopy and pulsed-field-gradient NMR diffusometry. Nation 112 exhibits biaxial alignment with its principal and secondary axes along two orthogonal in-plane directions. Both Nation 212 (NRE212) and block copolymers show uniaxial alignment with the symmetry axis perpendicular to the membrane plane. Our further discovery of the linear coupling between diffusion anisotropy and oritentational order parameter for mechanically stretched Nation 117 membranes strongly indicates that channel dimensions, domain structure, and defect character are unperturbed by the macroscopic mechanical deformation. When combining ionic liquids (ILs) with ionic polymers, ion associations result in up to 4X faster cation than anion diffusion at lower hydration levels and 3X slower cation diffusion at higher hydration levels. Conversely, we use ILs as probes to map local structures in ionic polymers. Ion diffusion coefficients exhibit strong dependencies on diffusion time, signifying the presence of sub-micron domain boundaries. Finally, we will discussapplication of electrophoretic NMR, which renders a promising opportunity to study ion transport and associations under electrochemical cell conditions.
机译：从燃料电池到电池再到离子换能器，各向异性，迁移和离子缔合关系决定着许多基于离子聚合物的材料和设备的性能。我们小组正在进行一系列NMR研究，并结合其他结构和形态学信息来理解这些复杂的材料。我们观察到在不同的全氟磺酸离聚物和基于芳香族的多嵌段共聚物中均匀排列的亲水通道，通过〜2H NMR光谱和脉冲场梯度NMR扩散法进行定量。国家112表现出其主轴线和副轴沿着两个正交的平面内方向的双轴对准。 Nation 212（NRE212）和嵌段共聚物都显示单轴排列，对称轴垂直于膜平面。我们对机械拉伸的Nation 117膜的扩散各向异性和取向序参数之间线性耦合的进一步发现强烈表明，宏观的机械变形不会干扰通道尺寸，畴结构和缺陷特征。当将离子液体（ILs）与离子聚合物结合使用时，离子缔合在低水合度下比阳离子扩散快多达4倍的阳离子，而在高水合度下比阳离子扩散快3倍。相反，我们使用IL作为探针来绘制离子聚合物中的局部结构。离子扩散系数对扩散时间具有很强的依赖性，表明存在亚微米域边界。最后，我们将讨论电泳NMR的应用，这为研究在电化学电池条件下的离子迁移和缔合提供了一个有希望的机会。

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  • 会议地点 Honolulu HI(US);Honolulu HI(US)
  • 作者

    Jianbo Hou; Jing Li; Kyle G. Wilmsmeyer; Zhiyang Zhang; Louis A. Madsen;

  • 作者单位

    Department of Chemistry and Macromolecules Interfaces and Institute,Virginia Tech, Blacksburg, VA 24061;

    Department of Chemistry and Macromolecules Interfaces and Institute,Virginia Tech, Blacksburg, VA 24061;

    Department of Chemistry and Macromolecules Interfaces and Institute,Virginia Tech, Blacksburg, VA 24061;

    Department of Chemistry and Macromolecules Interfaces and Institute,Virginia Tech, Blacksburg, VA 24061;

    Department of Chemistry and Macromolecules Interfaces and Institute,Virginia Tech, Blacksburg, VA 24061;

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  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 聚合反应过程;
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