Sangoro J R, Iacob C, Agapov A L, Wang Y, Berdzinski S, Rexhausen H, Strehmel V, Friedrich C, Sokolov A P, Kremer F
Department of Chemical & Biomolecular Engineering, University of Tennessee, Knoxville, Tennessee 37996-2200, USA.
Soft Matter. 2014 May 28;10(20):3536-40. doi: 10.1039/c3sm53202j. Epub 2014 Apr 10.
Charge transport and structural dynamics in low molecular weight and polymerized 1-vinyl-3-pentylimidazolium bis(trifluoromethylsulfonyl)imide ionic liquids (ILs) are investigated by a combination of broadband dielectric spectroscopy, dynamic mechanical spectroscopy and differential scanning calorimetry. While the dc conductivity and fluidity exhibit practically identical temperature dependence for the non-polymerized IL, a significant decoupling of ionic conduction from structural dynamics is observed for the polymerized IL. In addition, the dc conductivity of the polymerized IL exceeds that of its molecular counterpart by four orders of magnitude at their respective calorimetric glass transition temperatures. This is attributed to the unusually high mobility of the anions especially at lower temperatures when the structural dynamics is significantly slowed down. A simple physical explanation of the possible origin of the remarkable decoupling of ionic conductivity from structural dynamics is proposed.
通过宽带介电谱、动态力学谱和差示扫描量热法相结合的方法，研究了低分子量和聚合的1-乙烯基-3-戊基咪唑双（三氟甲基磺酰）亚胺离子液体（ILs）中的电荷传输和结构动力学。对于未聚合的离子液体，直流电导率和流动性表现出几乎相同的温度依赖性，而对于聚合的离子液体，观察到离子传导与结构动力学之间存在显著解耦。此外，在各自的量热玻璃化转变温度下，聚合离子液体的直流电导率比其分子对应物高出四个数量级。这归因于阴离子异常高的迁移率，特别是在较低温度下，此时结构动力学显著减慢。提出了对离子电导率与结构动力学显著解耦的可能起源的简单物理解释。
