Polymerized ionic liquid diblock copolymers with long alkyl side-chain length
Polymerized ionic liquid diblock copolymers with long alkyl side-chain length
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DOI：
10.1016/j.polymer.2014.04.003
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发表时间：
2014-08
期刊：
影响因子：
4.6
通讯作者：
Jacob R. Nykaza;Yuesheng Ye;Y. Elabd
中科院分区：
文献类型：
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作者：
Jacob R. Nykaza;Yuesheng Ye;Y. Elabd
以离子液体单体（1-[（2-甲基丙烯酰氧基）十一烷基]-3-丁基咪唑溴盐）（MUBIm-Br）和非离子单体甲基丙烯酸甲酯（MMA）为原料，合成了不同组成的含长烷基侧链的聚合离子液体（PIL）二嵌段共聚物poly（MMA-b-MUBIm-Br）。以反加成断裂链转移（RAFT）聚合法合成的非离子型PIL嵌段共聚物poly（MMA-b-BrUMA）（BrUMA =甲基丙烯酸11-溴十一烷基酯）为前驱体，通过接枝功能化反应合成了PIL嵌段共聚物。差示扫描量热法揭示了两个不同的恒定玻璃化转变温度（Tg）与低PIL segmentTg。这些PIL嵌段共聚物产生具有高机械强度的易于加工的柔性透明膜。在80 °C和90%RH下，对于具有1.44 meq/g的离子交换容量（IEC）（23.3摩尔% MUBIm-Br）的PIL二嵌段共聚物，测量到64.85 mS cm-1的高溴离子电导率。有趣的是，该结果比其类似的PIL均聚物（2.75meq/g; 100 mol% MUBIm-Br）高三倍，并且比来自先前研究的具有类似化学、类似IEC、更高水含量但更短烷基侧链长度的PIL嵌段共聚物高一个数量级。离子电导率没有如预期的那样随水含量而缩放，这对于水辅助离子传输是不寻常的（例如，质子，氢氧化物，氯离子），因此提出了影响PIL嵌段共聚物中离子传输的其他机制。
A polymerized ionic liquid (PIL) diblock copolymer with a long alkyl side-chain, poly(MMA-b-MUBIm-Br), was synthesized at various compositions from an ionic liquid monomer, (1-[(2-methacryloyloxy)undecyl]-3-butylimidazolium bromide) (MUBIm-Br), and a non-ionic monomer, methyl methacrylate (MMA). The PIL diblock copolymer was synthesizedviapost-functionalization from its non-ionic precursor PIL diblock copolymer, poly(MMA-b-BrUMA) (BrUMA = 11-bromoundecyl methacrylate), which was synthesizedviathe reverse addition fragmentation chain transfer (RAFT) polymerization technique. Differential scanning calorimetry reveals two distinct constant glass transition temperatures (Tgs) with a low PIL segmentTg. These PIL block copolymers result in easily processable, flexible, transparent films with high mechanical strength. A high bromide ion conductivity of 64.85 mS cm−1at 80 °C and 90% RH was measured for the PIL diblock copolymer with an ion exchange capacity (IEC) of 1.44 meq/g (23.3 mol% MUBIm-Br). Interestingly, this result was three times higher than its analogous PIL homopolymer (2.75 meq/g; 100 mol% MUBIm-Br) and an order of magnitude higher than a PIL block copolymer from a previous study with similar chemistry, similar IEC, higher water content, but shorter alkyl side-chain length. Ion conductivity did not scale as expected with water content, which is unusual for water-assisted ion transport (e.g., protons, hydroxide, chloride) in ion-containing polymers, and therefore suggests other mechanisms that impact ion transport in PIL block copolymers.