Won Kang, Hye published the artcileESR and NMR probes of counter-ion effects in perfluorosulfonate ionomer membranes, COA of Formula: C19H42F6NP, the publication is Journal of Membrane Science (1998), 148(2), 173-184, database is CAplus.
The properties of Nafion membranes, modified by exchange with tetraalkylammonium cations and equilibrated in methanol, were investigated using ESR spin probe techniques and 14N NMR spectroscopy. TEMPO and TEMPOL nitroxide radicals are shown to act as probes of the methanol solvent phase of the membranes. The mobility of the probe radicals is restricted, the correlation times for rotational diffusion being reduced by an order of magnitude within the ionomer environment compared to free methanol solution The larger tetraalkylammonium cations result in higher levels of swelling in methanol and a greater degree of nitroxide mobility. The temperature dependent ESR spectra show a gradual transition from freely diffusing to rigidly immobilized radicals as the temperature is lowered. The motion is completely frozen out at about 190 K, before the f.p. of methanol is reached. 14N NMR spectroscopy of the tetraalkylammonium counter-ions is also reported. The NMR signals for all cations remain quite sharp and well resolved in methanol-equilibrated Nafion. The corresponding 14N spin lattice relaxation times, T1, were reduced by one order of magnitude compared to methanol solution The long-chain surfactant cations showed the least reduction in T1 on incorporation into the membrane, consistent with retention of significant rotational mobility. These results are interpreted in terms of a much weaker ion clustering in the organically modified membranes than is found in strongly hydrated Nafion membranes.
Journal of Membrane Science published new progress about 101079-29-2. 101079-29-2 belongs to catalysis-chemistry, auxiliary class Surfactants, name is N-hexadecyltrimethylammoniumhexafluorophosphate, and the molecular formula is C23H43NP2, COA of Formula: C19H42F6NP.
Referemce:
https://courses.lumenlearning.com/boundless-chemistry/chapter/catalysis/,
Catalysis – Wikipedia