Dynamics of ionic liquids in the presence of polymer-grafted nanoparticles
Dynamics of ionic liquids in the presence of polymer-grafted nanoparticles
复制标题
DOI：
10.1039/c9nr04204k
复制
发表时间：
2019-11-14
期刊：
影响因子：
6.7
通讯作者：
Akcora, Pinar
中科院分区：
文献类型：
--
作者：
Liu, Siqi;Liedel, Clemens;Akcora, Pinar
我们采用准弹性中子散射（QENS）将聚合物接枝纳米粒子到离子和两性离子液体中，以探索溶剂化和限制对其非均相动力学的影响。研究了1-己基-3-甲基咪唑双（三氟甲基磺酰基）酰亚胺（HMIM-TFSI）与氘代聚甲基丙烯酸甲酯（d-PMMA）接枝纳米粒子的混合物，以揭示PMMA和HMIM-TFSI之间的动态耦合如何影响HMIM+阳离子的快扩散和慢扩散特性。两性离子液体，1-丁基-3-甲基咪唑-2-亚基硼烷（BMIM-BH 3）是严格选择和混合PMMA接枝的纳米粒子在这项工作中进行比较，因为它的离子不自解离，它不耦合与PMMA通过离子偶极相互作用的HMIM-TFSI。我们发现，远程无限制扩散的HMIM+阳离子是更高的分散良好的颗粒比聚集的颗粒系统，而本地化的扩散的HMIM+被测量到更高的密堆积的颗粒。BMIM-BH 3的平移扩散动力学不受任何粒子结构的影响，这表明两性离子不与PMMA相互作用。两种离子液体类型之间的这种差异使我们能够将聚合物效应与离子液体的扩散分离，这对于理解聚合物接枝纳米颗粒电解质中离子液体中的离子传输机制是不可或缺的。
We incorporated polymer-grafted nanoparticles into ionic and zwitterionic liquids to explore the solvation and confinement effects on their heterogeneous dynamics using quasi-elastic neutron scattering (QENS). 1-Hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (HMIM-TFSI) mixed with deuterated poly(methyl methacrylate) (d-PMMA)-grafted nanoparticles is studied to unravel how dynamic coupling between PMMA and HMIM-TFSI influence the fast and slow diffusion characteristics of the HMIM+ cations. The zwitterionic liquid, 1-butyl-3-methyl imidazole-2-ylidene borane (BMIM-BH3) is critically selected and mixed with PMMA-grafted nanoparticles for comparison in this work as its ions do not self-dissociate and it does not couple with PMMA through ion-dipole interactions as HMIM-TFSI does. We find that long-range unrestricted diffusion of HMIM+ cations is higher in well-dispersed particles than in aggregated particle systems, whereas the localized diffusion of HMIM+ is measured to be higher in close-packed particles. Translational diffusion dynamics of BMIM-BH3 is not influenced by any particle structures suggesting that zwitterions do not interact with PMMA. This difference between two ionic liquid types enables us to decouple polymer effects from the diffusion of ionic liquids, which is integral to understand the ionic transport mechanism in ionic liquids confined in polymer-grafted nanoparticle electrolytes.