Nafion® membranes were examined by transmission electron microscopy (TEM). Both solution casting and positive staining techniques were employed. The staining of solution-cast Nafion® membrane by RuO4 vapor led to good image contrast so that the ionic cluster domains in the membrane could be clearly observed. The TEM micrographs indicated the presence of three phases: ionic cluster phase, an organic matrix phase and an interfacial phase. The spherical ionic clusters were surrounded by the interracial phase and were uniformly distributed across the membrane; the average size of the clusters was found to be 25 to 50 Å. The staining mechanism was investigated by analyzing the ruthenium content of stained membranes by X-ray fluorescence spectroscopy and by comparing the FTIR spectra of stained and unstained membranes. It was concluded that the staining reaction involved the oxidation of absorbed water by RuO4 vapor to give RuO2 microparticles.
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Physical and Theoretical Chemistry
- Filtration and Separation