Effect of Superacidic Side Chain Structures on High Conductivity Aromatic Polymer Fuel Cell Membranes

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• 作者：Ying Chang ; Angela D. Mohanty ; Sarah B. Smedley ; Khaldoon Abu-Hakmeh ; Young Hun Lee ; Joel E. Morgan ; Michael A. Hickner ; Seung Soon Jang ; Chang Y. Ryu ; Chulsung Bae
• 刊名：Macromolecules
• 出版年：2015
• 出版时间：October 13, 2015
• 年：2015
• 卷：48
• 期：19
• 页码：7117-7126
• 全文大小：636K
• ISSN：1520-5835

文摘

Proton-conducting superacidic polymer membranes with different fluoroalkyl sulfonate pendants attached to aromatic polymer backbones were synthesized via C鈥揌 functionalization and Suzuki coupling reactions. Variation in the chemical structures of the pendant acidic sulfonate moieties and their effects on membrane properties including water uptake, ion exchange capacity, morphology, and proton conductivity were systemically investigated. Membranes containing the short 鈭扥CF₂SO₃H pendant (PSU-S₅) showed a smaller hydrophilic domain size and lower proton conductivity than those containing the longer pendants 鈭扥CF₂CF₂SO₃H (PSU-S₁) and 鈭扴CF₂CF₂SO₃H (PSU-S₄), likely due to the short chain鈥檚 less favorable aggregation and lower acidity. Polymer electrolyte membranes with unique branched fluoroalkyl sulfonate pendants (PSU-S₆) gave larger ionic domain sizes, more uniform hydrophilic channels, and higher proton conductivity than samples with analogous linear pendant chains (PSU-S₁), indicating that branched sulfonate structures may be a key future direction in the field of fuel cell membrane.