Enhanced charge transport in nano-confined ionic liquids
Enhanced charge transport in nano-confined ionic liquids
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DOI：
10.1039/c1sm06581e
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发表时间：
2012-01-01
期刊：
影响因子：
3.4
通讯作者：
Kremer, F.
中科院分区：
文献类型：
--
作者：
Iacob, C.;Sangoro, J. R.;Kremer, F.
采用宽带介电谱（BDS）和脉冲场梯度（PFG）-NMR相结合的方法研究了单向纳米多孔膜（孔径：7.5-10.4 nm）中离子液体的电荷输运。这使得人们能够确定超过13个十年的扩散系数和扩散速率，并跟踪其温度依赖性。在纳米限制的条件下，观察到从Vogel-Fulcher-Tammann到Arkenius样的热激活的变化，导致扩散系数增加两个数量级以上。随着孔径的减小，该效果变得更加明显。这归因于分子堆积的变化，从而导致密度的变化，从而导致更高的迁移率和电导率。
Charge transport in ionic liquids contained in unidirectional nanoporous membranes (pore diameters: 7.5-10.4 nm) is investigated by combining broadband dielectric spectroscopy (BDS) and pulsed field gradient (PFG)-NMR. This enables one to determine the diffusion coefficient and the diffusion rate over more than 13 decades and to trace its temperature dependence. Under conditions of nanometric confinement, a change from a Vogel-Fulcher-Tammann into an Arrhenius-like thermal activation is observed, resulting in an enhancement of diffusivities by more than two orders of magnitude. The effect becomes more pronounced with decreasing pore diameter. It is attributed to changes in molecular packing and hence in density leading to higher mobility and electrical conductivity.