Toward improved conductivity of sulfonated aromatic proton exchange membranes at low relative humidity

被引：207

作者：

Einsla, Melinda L. ^{[1
]}

Kim, Yu Seung ^{[1
]}

Hawley, Marilyn ^{[1
]}

Lee, Hae-Seung ^{[2
]}

McGrath, James E. ^{[2
]}

Liu, Baijun ^{[3
]}

Guiver, Michael D. ^{[3
]}

Pivovar, Bryan S. ^{[1
]}

机构：

[1] Los Alamos Natl Lab, Sensors & Elect Devices Grp, Los Alamos, NM 87545 USA

[2] Virginia Polytech Inst & State Univ, Macromol & Interfaces Inst, Blacksburg, VA 24061 USA

[3] Natl Res Council Canada, Inst Chem Proc & Environm Technol, Ottawa, ON K1A 0R6, Canada

来源：

CHEMISTRY OF MATERIALS | 2008年 / 20卷 / 17期

关键词：

D O I：

10.1021/cm801198d

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

Three sulfonated aromatic polymers with different sequence lengths were studied in order to better understand the relationship between molecular structure, morphology, and properties of proton exchange membranes as a function of relative humidity. A random copolymer with a statistical distribution of sulfonic acid groups had very small domain sizes, whereas an alternating polymer with sulfonic acid,groups spaced evenly along the polymer chain was found to have larger, but quite isolated, domains. The multiblock copolymer studied herein showed highly phase-separated hydrophilic and hydrophobic domains, with good long-range connectivity. Scanning force microscopy as a function of relative humidity was used to observe water absorption and swelling of the hydrophilic domains in each of the three membranes. The conductivity, water sorption kinetics. and fuel cell performance, especially at low relative humidity, were found to be highly dependent upon the morphology. The multiblock copolymer outperformed both the random and alternating systems at 100 degrees C and 40% RH fuel cell operating conditions and showed similar performance to Nation.

引用

页码：5636 / 5642

页数：7

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