Crystallization and Rheology of Poly(ethylene oxide) in Imidazolium Ionic Liquids

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• 作者：Fuyong Liu ; Yuxia Lv ; Jiajian Liu ; Zhi-Chao Yan ; Baoqing Zhang ; Jun Zhang ; Jiasong He ; Chen-Yang Liu
• 刊名：Macromolecules
• 出版年：2016
• 出版时间：August 23, 2016
• 年：2016
• 卷：49
• 期：16
• 页码：6106-6115
• 全文大小：562K
• 年卷期：0
• ISSN：1520-5835

文摘

Polymer and ionic liquid (IL) mixtures have attracted an increasing amount of attention due to their unique properties and potential applications. The interactions between poly(ethylene oxide) (PEO) and imidazolium ILs of different cation alkyl lengths and anion structures have been investigated by measuring melting points (T_m), contact angles, and rheological properties. T_m of crystalline PEO dramatically decreased when it was blended with ILs. Similarly, the contact angles of different ILs on a PEO surface proportionally decreased. The interaction energy, as calculated from melting point depression using the Flory equation, increased with the length of imidazolium alkyl cations and the size of anions. The different anionic structures had a more significant influence on the interaction energy than the alkyl chain lengths of cations. These trends accorded with the solubility obtained by high-energy X-ray diffraction and swelling ratio measurements of PEO in different ILs [Asai Macromolecules 2013, 46, 2369−2375] and the solubility of poly(methyl methacrylate) in different ILs [Ueno Langmuir 2014, 30, 3228−3235]. The rheological behavior of PEO in three different anionic ILs has also been studied to determine the effect of the anions on PEO conformations. The molecular weight dependence of the intrinsic viscosity of PEO in ILs revealed that the solvent quality of ILs (from poor solvents to good solvents) is highly influenced by anionic structures, which was consistent with the results of the melting point depression and contact angle.