Hot-Pressing Effects on Polymer Electrolyte Membrane Investigated by ~2H NMR Spectroscopy

摘要

The structural change of Nafion polymer electrolyte membrane (PEM) induced by hot-pressing, which is one of the representative procedures for preparing membrane-electrode-assembly for low temperature fuel cells, was investigated by ~2H nuclear magnetic resonance (NMR) spectroscopy. The hydrophilic channels were asymmetrically flattened and more aligned in the membrane plane than along the hot-pressing direction. The average O-~2H director of ~2H2O in polymer electrolyte membrane was employed to extract the structural information from the ~2H NMR peak splitting data. The dependence of ~2H NMR data on water contents was systematically analyzed for the first time. The approach presented here can be used to understand the chemicals' behavior in nano-spaces, especially those reshaping and functioning interactively with the chemicals in the wet and/or mixed state.