Quantitative Analysis of Conductivity and Viscosity of Ionic Liquids in Terms of Their Relaxation Times
Quantitative Analysis of Conductivity and Viscosity of Ionic Liquids in Terms of Their Relaxation Times
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根据弛豫时间对离子液体的电导率和粘度进行定量分析
DOI：
10.1021/jp502631q
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发表时间：
2014
影响因子：
3.3
通讯作者：
Shinobu Koda
中科院分区：
文献类型：
--
作者：
Tsuyoshi Yamaguchi;Eiichiro Nakahara;Shinobu Koda
实验测量了不同离子液体的频率相关粘度和电导率，并测定了它们的平均弛豫时间。粘度和电导率的松弛时间与它们各自的零频极限值近似相关。然而，沃尔登乘积似乎与粘度的松弛时间与电导率的松弛时间的比率总体上没有相关性。当阳离子的烷基链与丁基一样短时，粘度较大的离子液体在两个驰豫时间和较大的Walden积之间往往表现出较大的差异。延长阳离子的烷基链减少了沃尔登乘积，但略微增加了松弛时间比，这是通过高频剪切模数的降低来解释的。此外，以烷基链最长的离子液体1-十二基-3-甲基咪唑双(三氟甲基磺酰基)酰胺为例，讨论了介观结构对粘度的贡献。
The frequency-dependent viscosity and conductivity of various ionic liquids were measured experimentally, and their mean relaxation times were determined. The relaxation times of the viscosity and conductivity were approximately correlated with their respective zero-frequency limiting values. The Walden products, however, appeared to have no correlation with the ratio of the relaxation time of viscosity to that of conductivity in general. When the alkyl chain of the cation is as short as butyl, more viscous ionic liquids tend to show larger difference between two relaxation times and larger Walden products. Lengthening the alkyl chain of the cation decreases the Walden product while slightly increasing the relaxation time ratio, which was elucidated in terms of the decrease in the high-frequency shear modulus. In addition, the contribution of the mesoscopic structure to viscosity was suggested in the case of the ionic liquid with the longest alkyl chain studied in this work, 1-dodecyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide.