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Temperature‐ and Humidity‐Controlled SAXS Analysis of Proton‐Conductive Ionomer Membranes for Fuel Cells
Author(s) -
Mochizuki Takashi,
Kakinuma Katsuyoshi,
Uchida Makoto,
Deki Shigehito,
Watanabe Masahiro,
Miyatake Kenji
Publication year - 2014
Publication title -
chemsuschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.412
H-Index - 157
eISSN - 1864-564X
pISSN - 1864-5631
DOI - 10.1002/cssc.201301322
Subject(s) - ionomer , small angle x ray scattering , membrane , nafion , chemical engineering , materials science , polymer chemistry , polymer , proton exchange membrane fuel cell , ionic bonding , hydronium , copolymer , chemistry , molecule , scattering , composite material , organic chemistry , electrochemistry , ion , electrode , biochemistry , physics , optics , engineering
We report herein temperature‐ and humidity‐controlled small‐angle X‐ray scattering (SAXS) analyses of proton‐conductive ionomer membranes. The morphological changes of perfluorosulfonic acid polymers (Nafion and Aquivion) and sulfonated aromatic block copolymers (SPE‐ bl ‐1 and SPK‐ bl ‐1) were investigated and compared under conditions relevant to fuel cell operation. For the perfluorinated ionomer membranes, water molecules were preferentially incorporated into ionic clusters, resulting in phase separation and formation of ion channels. In contrast, for the aromatic ionomer membranes, wetting led to randomization of the ionic clusters. The results describe the differences in the proton‐conducting behavior between the fluorinated and nonfluorinated ionomer membranes, and their dependence on the humidity.