Preparation and characterization of high-durability zwitterionic crosslinked proton exchange membranes

✍ Scribed by Yun-Sheng Ye; Wen-Yi Chen; Yao-Jheng Huang; Ming-Yao Cheng; Ying-Chieh Yen; Chih-Chia Cheng; Feng-Chih Chang

• Publisher: Elsevier Science
• Year: 2010
• Tongue: English
• Weight: 525 KB
• Volume: 362
• Category: Article
• ISSN: 0376-7388
• DOI: 10.1016/j.memsci.2010.06.004

✦ Synopsis

The present paper describes the development of a novel proton exchange membrane comprising a poly (styrene sulfonic acid-co-4-vinylpyridine) copolymer that was crosslinked with a haloalkyl crosslinker through the formation of ionic bonding linkages. The nucleophilic substitution of these crosslinked membranes as well as a model reaction between pyridine and 1-bromobutane was confirmed by nuclear magnetic resonance (NMR). Tough and flexible membranes of a high mechanical strength were prepared. They demonstrated very elevated thermal, hydrolytic and oxidative stabilities as compared to other sulfonated polymers. The crosslinked membrane composed of zwitterionic molecules with a crosslinking fraction of 90.3, denoted SP-1, exhibited a proton conductivity of ca. 7.1 × 10 -2 S cm -1 at 30 • C under 90% relative humidity; a value comparable to that of Nafion 117. Moreover, the crosslinked SP-1 membrane possessed the highest selectivity for methanol fuel cells (3.38 × 10 5 S cm -3 s), approximately five times that of Nafion 117, thus implying its potential for practical use in high-energy-density devices.