Scaling Relation and Rheological Behaviors of Polymerized Ionic Liquids in Ionic Liquid/Dimethylformamide Solutions,Macromolecules

当前位置： X-MOL 学术 › Macromolecules › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

Scaling Relation and Rheological Behaviors of Polymerized Ionic Liquids in Ionic Liquid/Dimethylformamide Solutions
Macromolecules ( IF 5.1 ) Pub Date : 2024-08-27 , DOI: 10.1021/acs.macromol.4c01005
Gang Liu ₁ , Huan Luo ₂ , Yongjie Dan ₁ , Yanhua Niu ₁ , Guangxian Li ₁

Affiliation

As a special class of polyelectrolytes, polymerized ionic liquids (PILs) possess large counterions in their size, and the complicated electrostatic interactions with added salts, especially ILs, have attracted lots of attention. In this work, the conformational change and scaling relation of an imidazolium-based polycation (poly[1-(4-vinylbenzyl)-3-methylimidazolium bis(trifluoromethylsulfonyl)imide] (P[VBMIM][TFSI])) in a nonionic solvent [dimethylformamide (DMF)] are investigated in detail by combining rheology and light scattering under the influence of an added salt [IL 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C₂mim][TFSI])] with different concentrations c_salt. The hydrodynamic radius R_H of PILs and the specific viscosity η_sp show two different trends on the dependence of added salt concentration: chain collapsing due to charge screening at low c_salt and chain “reswelling” due to strong ion correlations at high c_salt (>3 M). Rheological viscosities show strong dependence on c_salt, presenting a transition from salt-free polyelectrolytes (scaling exponent ν = 1) to good solvents (ν = 0.588), and the numerical coefficient B at different c_salt regimes is also estimated. For clear quantification, the Flory–Huggins interaction parameter χ and chain dynamics for PIL molecules at various c_salt are calculated by the molecular dynamics simulations, which further validate results of light scattering and rheological measurements. This study could help to clearly quantify the chain conformation and rheological scaling of PIL solutions and give useful guidance to their processing and applications.

中文翻译：

聚合离子液体在离子液体/二甲基甲酰胺溶液中的结垢关系和流变行为

作为一类特殊的聚电解质，聚合离子液体（PIL）具有较大的抗衡离子，与添加的盐（特别是离子液体）之间复杂的静电相互作用引起了人们的广泛关注。在这项工作中，咪唑基聚阳离子（聚[1-（4-乙烯基苄基）-3-甲基咪唑鎓双（三氟甲基磺酰基）亚胺]（P[VBMIM][TFSI]））在非离子溶剂中的构象变化和缩放关系[二甲基甲酰胺 (DMF)] 通过在添加盐 [IL 1-乙基-3-甲基咪唑鎓双(三氟甲基磺酰基)亚胺 ([C ₂ mim][TFSI])] 的影响下结合流变学和光散射进行详细研究浓度c_盐。 PIL 的流体动力学半径R _H和比粘度 η _sp显示出与添加盐浓度相关的两种不同趋势：由于低c_盐下的电荷屏蔽而导致链塌陷，以及由于高c_盐下的强离子相关性而导致的链“再溶胀”（ >3 M）。流变粘度显示出对c_盐的强烈依赖性，呈现从无盐聚电解质（标度指数 ν = 1）到良溶剂（ν = 0.588）的转变，并且还估计了不同c_盐状态下的数值系数B。为了清晰定量，通过分子动力学模拟计算了不同c_盐下 PIL 分子的 Flory-Huggins 相互作用参数 χ 和链动力学，这进一步验证了光散射和流变测量的结果。这项研究有助于清楚地量化 PIL 溶液的链构象和流变尺度，并为其加工和应用提供有用的指导。

更新日期：2024-08-27

点击分享查看原文

点击收藏

阅读更多本刊新发论文本刊介绍/投稿指南