Percolated Ionic Aggregate Morphologies and Decoupled Ion Transport in Precise Sulfonated Polymers Synthesized by Ring-Opening Metathesis Polymerization
Percolated Ionic Aggregate Morphologies and Decoupled Ion Transport in Precise Sulfonated Polymers Synthesized by Ring-Opening Metathesis Polymerization
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DOI：
10.1021/acs.macromol.0c01906
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发表时间：
2020-10-27
期刊：
影响因子：
5.5
通讯作者：
Winey, Karen, I
中科院分区：
文献类型：
--
作者：
Paren, Benjamin A.;Thurston, Bryce A.;Winey, Karen, I
我们描述了一组精确的单离子导电聚合物，它们在玻璃聚合物基质中形成自组装的渗透离子聚集体，并具有金属阳离子的解耦传输。这些精确的单离子导体（sic）是通过可扩展的开环复分解聚合合成的，由聚乙烯骨架和每五个碳上的磺化苯基组成，并被反离子X+ （Li+， Na+或Cs+）完全中和。实验x射线散射测量结果与全原子分子动力学（MD）模拟结果吻合良好。MD模拟结果表明，离子基纳米相从聚合物骨架中分离出来，形成渗透的离子聚集体。利用图论，我们发现在Li+和Na+中和的聚合物中，渗透聚集体在中等长度尺度上表现为平面和带状结构，而Cs+中和的聚合物中渗透聚集体则更具各向同性。电阻抗谱测量表明，离子电导率表现出阿伦尼乌斯行为，在180℃时的电导率为10（-7）至10(-6)S/cm。在MD模拟中，阳离子在渗透聚集体中的磺酸基之间移动，较大的离子移动得更远，总体阳离子比聚合物骨架移动得更远，表明离子传输机制解耦。因此，这些聚合物中渗透的离子聚集体可以作为促进解耦离子运动通过玻璃聚合物基质的途径。
We describe a set of precise single-ion conducting polymers that form self-assembled percolated ionic aggregates in glassy polymer matrices and have decoupled transport of metal cations. These precise single-ion conductors (SICs), synthesized by a scalable ring-opening metathesis polymerization, consist of a polyethylene backbone with a sulfonated phenyl group pendant on every fifth carbon and are fully neutralized by a counterion X+ (Li+, Na+, or Cs+). Experimental X-ray scattering measurements and fully atomistic molecular dynamics (MD) simulations are in good agreement. The MD simulations show that the ionic groups nanophase separate from the polymer backbone to form percolating ionic aggregates. Using graph theory, we find that within the Li+- and Na+-neutralized polymers the percolated aggregates exhibit planar and ribbon-like configurations at intermediate length scales, while the percolated aggregates within the Cs+-neutralized polymers are more isotropic. Electrical impedance spectroscopy measurements show that the ionic conductivities exhibit Arrhenius behavior, with conductivities of 10(-7) to 10(-6) S/cm at 180 degrees C. In the MD simulations, the cations move between sulfonate groups in the percolated aggregates, larger ions travel further, and overall cations travel further than the polymer backbones, indicating a decoupled ion-transport mechanism. Thus, the percolated ionic aggregates in these polymers can serve as pathways to facilitate decoupled ion motion through a glassy polymer matrix.