FTIR spectroscopic study of the interaction between NH4+ and DMSO in Nafion.

Nafion-NH4+ membranes plasticized with dimethyl sulfoxide (DMSO and DMSO-d6) have been investigated at room temperature using the vacuum ATR-FTIR and FTIR absorption spectroscopic technique in the range 50-4000 cm-1. The amount of the plasticizer corresponds to the molecular ratio n = DMSO/NH4+ = 2.7-13.8. The mutual association of free DMSO molecules in Nafion leads to appearance of weak band at 86 cm-1 assigned to dipole-dipole interactions. Also the Raman spectra of dry Nafion-NH4+ membranes were investigated.

FTIR spectroscopic study of the complex formation between H+ and DMSO in Nafion.

Nafion membranes plasticized with dimethyl sulfoxide (DMSO) have been examined at room temperature using the vacuum ATR - FTIR spectroscopic technique in the range 50-4000cm-1. The amount of the plasticizer corresponds to the molecular ratio n=DMSO/H+=1.2, 2.3, 4.8, 7.0, 9.7 and 13.3. The medium intensity band with two maxima at 780 and 853cm-1 have been assigned to the ν(SO) stretching vibrations of the H+(DMSO)2 complex. The possible reason of ν(SO) splitting is symmetry decrease of hydrogen bond under the influence of the anion group SO3- electric field. Whereas the mutual association of free DMSO molecules in Nafion leads to appearance of weak band at 86cm-1 assigned to the dipole-dipole interactions.