Water states and dynamics in perfluorinated ionomer membranes by 1H one- and two-dimensional NMR spectroscopy, relaxometry, and diffusometry

The possibility to characterize the water states, the molecules rotational and translational diffusion, exchange, and their anisotropy in fully hydrated undegraded and chemically degraded Nafion 117 is discussed. To this purpose T1, T2, and D, Laplace spectra as well as T1–T2 correlation spectroscopy (COSY), T2–T2 exchange spectroscopy (EXSY), T1–D, and D–T2 Laplace–Laplace COSY spectroscopy were employed. The spectra of T2–T2 EXSY were proved to be most informative for detecting three water states and the exchange between the corresponding water reservoirs.