Ionics of polymerized ionic liquids

本研究的目的是合成由室温离子液体结构组成的聚合物及其在固体膜中作为离子导电材料的应用。今年，我们利用对作为模型化合物制备的各种低分子量咪唑鎓盐的知识，研究了新型离子液体的聚合。制备了多种带有乙烯基的咪唑鎓盐。然后将它们均聚或与其他单体共聚。通过在聚合物主链和咪唑鎓单元之间引入间隔基，或引入降低体系Tg的单元，可以提高离子的迁移率。此外，考虑到作为电子器件的应用，我们还制备了一些能够选择性地传输目标离子的系统。通过添加LiTFSI和在电位梯度下不迁移的两性离子液体，我们设计了一种仅锂阳离子可移动的聚合物基体。采用激光拉曼光谱分析聚合物基体中盐的解离度。到目前为止，尚未阐明为什么尽管基质的链段迁移率较高，但某些体系的离子电导率没有得到改善。该方法能够研究盐的解离程度，以证明大量未解离的盐会对系统产生负面影响。我们还制备了含硼聚合物，其中通过缺电子有机硼单元的阴离子捕获效应可以选择性地进行阳离子传输。对于所有制备的含硼体系，锂转移数均超过0.6。生物分子在离子液体中的溶解也成功。经过聚环氧乙烷修饰后，将细胞色素c溶解在离子液体中。我们通过光波导光谱研究了它们的热稳定性。结果表明，PEO修饰的细胞色素c的氧化还原反应在140℃下仍能稳定进行。

The purpose of this study is synthesis of polymers composed of room temperature ionic liquid structure and their application as ion conductive materials in solid film. In this year, we have examined polymerization of novel ionic liquids taking advantage of our knowledge on various low molecular weight imidazolium salts prepared as model compounds. A variety of imidazolium salts bearing vinyl group were prepared. They were then homopolymerized or copolymerized with other monomers. The mobility of ions was improved by introducing spacer between polymer main chain and imidazolium unit, or incorporating a unit which reduces Tg of systems. Furthermore, in view of application as electronic devices, we have also prepared some systems which are capable of transporting target ion selectively. By adding LiTFSI and zwitterionic liquid which does not migrate under potential gradient, we have designed a polymer matrix in which only lithium cation is mobile. The dissociation degree of salt in polymer matrix was analyzed by laser Raman spectroscopy. It has not been clarified so far why ionic conductivity is not improved for some systems in spite of higher segmental mobility of matrix. This method enabled to investigate the dissociation degree of salt to demonstrate that a considerable amount of undissociated salts was found to affect negatively in the system.We have also prepared boron containing polymers in which selective cation transport was possible via anion trapping effect of electron deficient organoboron unit. For all the boron containing systems prepared, lithium transference number exceeded 0.6.Dissolution of biomolecules in ionic liquids was also successful. After poly(ethylene oxide) modification, cytochrome c was dissolved in ionic liquid. We have studied their thermal stability by optical waveguide spectroscopy. It was demonstrated that oxidation and reduction of PEO modified Cytochrome c was stably carried out up to 140℃.