Ion gels prepared by in situ radical polymerization of vinyl monomers in an ionic liquid and their characterization as polymer electrolytes
Ion gels prepared by in situ radical polymerization of vinyl monomers in an ionic liquid and their characterization as polymer electrolytes
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DOI：
10.1021/ja045155b
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发表时间：
2005-04-06
影响因子：
15
通讯作者：
Watanabe, M
中科院分区：
文献类型：
--
作者：
Susan, MA;Kaneko, T;Watanabe, M
为了实现具有高离子电导率的聚合物电解质，我们利用了离子液体的高离子电导率。在室温离子液体1-乙基-3-甲基咪唑双(三氟甲烷磺酰)亚胺(EMITFSI)中，相容的乙烯基单体进行原位自由基聚合，得到了一系列新型的聚合物电解质。由甲基丙烯酸甲酯(MMA)在EMITFSI中聚合而成的聚合物凝胶，在少量交联剂的存在下，可获得自立、灵活和透明的薄膜。凝胶的玻璃化转变温度随EMITFSI摩尔分数的增加而降低，表现为聚甲基丙烯酸甲酯(PMMA)和EMITFSI完全相容的二元体系。离子凝胶的离子电导率与温度的关系符合Vogel-Tamman-Fulcher(VTf)方程，室温下的离子电导率接近10(-2)S cm(-1)。与离子液体的行为相似，离子凝胶中的阳离子比阴离子扩散得更快。根据奈姆斯特-爱因斯坦方程计算，离子凝胶的载流子离子数量比离子液体本身的相应值有所增加。阳离子转移数随着EMITFSI浓度的降低而增加，这是因为PIVA基质和TFSI-离子之间的相互作用阻止了离子簇或缔合的形成，就像离子液体本身一样。
To realize polymer electrolytes with high ionic conductivity, we exploited the high ionic conductivity of an ionic liquid. In situ free radical polymerization of compatible vinyl monomers in a room temperature ionic liquid, 1-ethyl-3-methyl imiclazolium bis(trifluoromethane sulfonyl)imide (EMITFSI), afforded a novel series of polymer electrolytes. Polymer gels obtained by the polymerization of methyl methacrylate (MMA) in EMITFSI in the presence of a small amount of a cross-linker gave self-standing, flexible, and transparent films. The glass transition temperatures of the gels, which we named "ion gels", decreased with increasing mole fraction of EMITFSI and behaved as a completely compatible binary system of poly(methyl methacrylate) (PMMA) and EMITFSI. The temperature dependence of the ionic conductivity of the ion gels followed the Vogel-Tamman-Fulcher (VTF) equation, and the ionic conductivity at ambient temperature reached a value close to 10(-2) S cm(-1). Similarly to the behavior of the ionic liquid, the cation in the ion gels diffused faster than the anion. The number of carrier ions, calculated from the Nemst-Einstein equation, was found to increase for an ion gel from the corresponding value for the ionic liquid itself. The cation transference number increased with decreasing EMITFSI concentration due to interaction between the PIVIVA matrix and the TFSI- anion, which prohibited the formation of ion clusters or associates, as was the case for the ionic liquid itself.