Polymerized ionic liquids (PILs) with anions of bis(trifluoromethylsulfonyl)imide (TFSI^–), hexafluorophosphate (PF₆^–), and tetrafluoroborate (BF₄^–) and cations of poly[1-(4-vinylbenzyl)-3-alkyl-imidazolium] P[VBC_nIM]⁺ with alkyl lengths C₁, C₂, and C₄ were successfully synthesized and characterized. X-ray scattering showed an increase in backbone-to-backbone spacing (d_b) by 0.8 Å per CH₂ added to the alkyl side chain. Rheological and dielectric measurements were used to measure rates of chain relaxation and ion dissociation/association. The glass transition temperatures T_g follow the trend: PC₄-TFSI < PC₂-TFSI < PC₁-TFSI < PC₁-BF₄ < PC₁-PF₆, which correlates well with their dielectric behaviors. However, the fragility m_DR from dielectric relaxation increases with decreasing T_g, which is the opposite of the dependence of fragility m_Rheo from rheology for both our PILs and neutral polymers. The dielectric and rheological relaxations of our PILs are expected to be influenced by both their anion–cation binding energies and their relative free volumes, while for neutral polymers, relaxations are primarily governed by free volume. The increase of fragility of m_DR with decreasing T_g, therefore, suggests that dielectric relaxation is influenced more by anion–cation binding energy than by free volume, while the reverse is true for m_Rheo. The plateau modulus G_N and entanglement molecular weight M_e estimated from rheological measurements agree with predictions of the packing model, using only a small modification of the Flory characteristic ratio C_∞ from that of a neutral polymer. Packing lengths of p = 6.0∼9.3 Å and tube diameters d_t = 11∼17 nm are found, depending on specific cation and anion structures.

中文翻译：

---

聚合离子液体与各种阴离子/阳离子的多重弛豫和纠缠行为


具有双（三氟甲基磺酰基）酰亚胺 （TFSI^–）、六氟磷酸盐 （PF₆^–） 和四氟硼酸盐 （BF₄^–） 阴离子以及烷基长度为 C₁、C₂ 和 C₄ 的聚[1-（4-乙烯基苄基）-3-烷基咪唑] P[VBC_nIM]⁺ 阳离子的聚合离子液体 （PIL）成功合成和表征。X 射线散射显示，每添加到烷基侧链的 CH₂ 中，主链到主链间距 （d_b） 增加 0.8 Å。流变学和介电测量用于测量链弛豫和离子解离/缔合的速率。玻璃化转变温度 T_g 遵循以下趋势：PC_4-TFSI < PC_2-TFSI < PC_1-TFSI < PC_{1-BF 4} < PC_{1-PF 6}，这与它们的介电行为密切相关。然而，介电弛豫产生的脆性 m_DR 随着 T_g 的降低而增加，这与流变学对 PIL 和中性聚合物的脆性 m_Rheo 的依赖性相反。我们的 PIL 的介电和流变弛豫预计会受到其阴离子-阳离子结合能和相对自由体积的影响，而对于中性聚合物，弛豫主要受自由体积控制。 因此，m_DR 的脆性随着 T_g 的降低而增加，这表明介电弛豫受阴离子-阳离子结合能的影响大于自由体积的影响，而 m_Rheo 则相反。根据流变学测量估计的平台模量 G_N 和缠结分子量 M_e 与堆积模型的预测一致，仅使用 Flory 特征比 C_∞ 的少量修改来自中性聚合物的特性比。发现堆积长度为 p = 6.0∼9.3 Å，管径 d_t = 11∼17 nm，具体取决于特定的阳离子和阴离子结构。