| Abstract: | We explore the effects of hydration on the vibrational spectra of cation‐exchanged Nafion thin films. In addition to the initial H+ form of the membrane, the cations selected for study include: Na+, NH , tetramethylammonium, tetrabutylammonium, hexadecyltrimethylammonium, and tris(2,2′‐bipyridine)osmium(II). A flow cell is used to follow the changes occurring in a 1000‐Å film in response to variations in the humidity of a nitrogen purge gas flowing through the cell. The structural changes occurring due to the binding of water to these cation‐exchanged membranes is followed across a broad range of water contents with IR difference spectroscopy. Our results demonstrate a complex role for water in mediating the polyanion–cation interactions. Side‐chain reconstructions may play an important role in the ion‐binding and transport properties of the ionomer domains. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 1512–1520, 2000 |
