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第 1 期 韩 旭，等: 纳米 TiO 2 增强阴离子导电膜中碱性离子液体稳定性
碱时间的增加而逐渐减弱，说明季铵基团在泡碱过
程中不断发生降解。
2.8 离子液体流失率测定
高湿环境下，PVA 骨架由于膜的溶胀会变得松
散，[DMPy][OH]碱性离子液体会从 PVA 骨架中流
失，导致膜性能下降。因此，有必要对复合膜中离
子液体流失情况进行考察。本文将复合膜在室温下
完全浸泡于去离子水中，测定浸泡前后复合膜的
IEC 值，计算膜中离子液体流失率，结果见图 10。
图 10 P-X 和 PT-X 复合膜的离子液体流失率
Fig. 10 [DMPy][OH] loss rate of P-X and PT-X composite
membranes
由图 10 可知，离子液体流失率随着膜内离子液
体含量的增加而逐渐增大，这是因为膜内空间体系
能稳定存在的离子液体数量是有限的，离子液体数
量超过临界值，多余的部分就会以游离的状态存在
于膜中，极易流失。而添加 Nano-TiO 2 后，复合膜
中离子液体流失率大幅降低，这是因为处于游离态
的离子液体在自组装作用下被吸附到 Nano-TiO 2 表
面，形成复合颗粒，而 Nano-TiO 2 中 Ti—O 的强极性
可以使吸附的水分子发生解离生成钛羟基
基又可以与 PVA 中的羟基形成氢键，使其被固载到
PVA 骨架上，从而使离子液体较稳定地存在于膜结
构中。其中，PT-25 由于 Nano-TiO 2 的添加，复合膜
的离子液体流失率降幅约 34.3%，表明 Nano-TiO 2 的
添加对离子液体的流失有一定的抑制作用。
3 结论
通过共混-流延法制备 PVA-[DMPy][OH]-TiO 2
复合膜，借助 GA 的化学交联作用使复合膜具备半
互穿的网状结构。该系列复合膜具有制备工艺简单、
环境友好等特点，同时具有较高的电导率，良好的机
械性能，优异的热稳定性、耐碱稳定性。结果表明，
当[DMPy][OH]质量分数为 25%时，PT-25 在 80 ℃的
3
电导率为 2.78×10 S/cm；在室温下 3 mol/L KOH 中
进行加速老化实验，120 h 后，电导率无明显变化，
表现出优异的耐碱稳定性；热分解温度高于 200 ℃；
·135·
室温浸泡于水中 12 h 后，离子液体流失率也仅为
23.2%。PVA-[DMPy][OH]-TiO 2 复合膜具备在燃料电
池中应用的潜力。
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