| Popis: |
Our laboratory's main activity in connection with this grant has been to develop and implement NMR-based analytical tools to characterize water, methanol, and charge transport in PEM membrane materials provided by research collaborators at other universities and research centers, including AFRL. NMR spectroscopy provides information on different structural environments of multicomponent PEM films, for example those containing phosphoric acid and ionic liquids. Dynamical processes are probed at the short range by spin-lattice relaxation measurements while pulsed field gradient techniques are used to obtain self-diffusion coefficients of water and methanol. Among the systems investigated were high phosphoric acid content polybenzimidazole (PBI) films, sulfonated polyarylene thioether sulfones, NAFION nanocomposites, and sufonated polyetherether ketone (SPEEK) nanocomposites. A new high throughput measurement scheme based on one-dimensional magnetic resonance imaging was developed that facilitates rapid screening of multiple samples. |
