Effect of Ionic Liquid Components on the Coil Dimensions of PEO
Effect of Ionic Liquid Components on the Coil Dimensions of PEO
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DOI：
10.1021/acs.macromol.9b00354
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发表时间：
2019-04-23
期刊：
影响因子：
5.5
通讯作者：
Lodge, Timothy P.
中科院分区：
文献类型：
--
作者：
Kharel, Aakriti;Lodge, Timothy P.
采用小角中子散射法测量了不同咪唑基苯胺(1-丁基-3-甲基咪唑双（三氟甲基磺酰基）亚胺（[BMIM][TFSI]）、1-丁基-3-甲基咪唑六氟磷酸盐（[BMIM][PF6]）在分子量范围（10-250 kg/mol）内的无限旋转稀释半径（R-g,R-0）。和1-己基-3-甲基咪唑四氟硼酸盐（[HMIM][BF4]）)在0.58 ~ 0.60之间，表现出良好的溶剂性。d-PEO的线圈尺寸随着阳离子烷基链长度的增加和阴离子碱度的降低而增加。与依赖于阳离子烷基链长度相比，改变阴离子对线圈尺寸的影响更明显。在1-乙基-3-甲基咪唑四氟硼酸盐（[EMIM][BF4]）中，R-g，R-0的温度依赖性是中等的，当温度从80℃升高到135℃时，线圈尺寸减小。在d-PEO和[BMIM] [TFSI]的混合物中添加高达10%的盐，锂二（三氟甲基磺酰基）亚胺，对R-g，R-0没有显著影响。这些结果讨论了PEO，阳离子和阴离子之间的相对相互作用。
Small-angle neutron scattering is used to measure the infinite dilution radius of gyration (R-g,R-0) for a range of molecular weights (10-250 kg/mol) of perdeuterated poly(ethylene oxide) (d-PEO) in various imidazolium-based ILs at 80 degrees C. The Flory exponents (v) evaluated in the ILs studied (1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([BMIM][TFSI]), 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]), and 1-hexyl-3-methylimidazolium tetrafluoroborate ([HMIM][BF4])) lie between 0.58 and 0.60, indicating good solvent behavior. The coil dimensions of d-PEO increase on increasing the alkyl chain length of the cation and on decreasing the anion basicity. A more pronounced effect on coil dimensions is observed upon altering the anion, compared to the dependence on cation alkyl chain length. The temperature dependence of R-g,R-0 is found to be moderate in 1-ethyl-3-methylimidazolium tetrafluoroborate ([EMIM][BF4]), where the coil size decreases upon increasing the temperature from 80 to 135 degrees C. Addition of up to 10 wt % of a salt, lithium bis(trifluoromethylsulfonyl)imide, to mixtures of d-PEO and [BMIM] [TFSI] has no significant effect on R-g,R-0. These results are discussed in terms of the relative interactions among PEO, the cation, and the anion.