Observation of electrophoretic nuclear magnetic resonance imaging in polymer electrolyte

We studied proton dynamics in polymer electrolyte by nuclear magnetic resonance imaging (NMR imaging or MRI) combined with D.C. electric field. Two pulse sequences: Spin-Echo and RARE (rapid acquisition with relaxation enhancement techniques) methods are used to obtain the spin density distribution in the membrane and fine time resolution images. Migration process of water from anode to cathode was observed by NMR imaging while applying d.c. electric field. The diffusion coefficient evaluated from proton mobility measured by NMR imaging and self-diffusion coefficient measured by pulse-field gradient method has almost same order of magnitude. The intensity enhancement in the vicinity of Pt electrode was detected when d.c. polarity was inverted. It implies attracted protons (H⁺) on Pt electrode react with dissolved oxygen gases to generate water.