INTERACTION OF THE PERFLUORINATED POLYMER NAFION-H WITH WATER STUDIEDBY PROTON BROAD-LINE NMR AT 4 K AND MAS NMR AT ROOM-TEMPERATURE

Broad-line H-1 NMR at 4 K shows that, when Nafion-H interacts with wat er molecules at low concentrations, the only species formed is the hyd ronium ion. The chemical shift of the unsolvated hydronium ion in Nafi on-H with 1 H2O/SO3-, determined by H-1 MAS NMR at room temperature, i s 10.4 ppm relative to external TMS.