RAMAN-SPECTRA OF PPO SALT COMPLEXES - MIXED CATIONS AND MIXED ANIONS

Complexes of poly(propylene oxide) with mixed salts of composition LiK1-xCF3SO3(PPO)10 and Na(CF3SO3)x-(SCN)1-x(PPO)10 have been studied by Raman spectroscopy. The nu(s)(SO3-) spectral region was analyzed in terms of the relative amounts of dissociated ions, ion pairs and aggregate species present as a function of relative mixed ion concentration x. The results indicate that the intensity ratios of the total aggregates and the dissociated CF3SO3- anions have a minimum and a maximum in the mixed cation polymer complexes, respectively. The intensity ratios of K+.CF3SO3- ion pairs and Li+.CF3SO3- ion pairs show negative and positive deviation, respectively, from ideality. Therefore the intensity ratio of the total ion pairs shows a small non-linearity in the mixed cation region. In contrast to the mixed cation polymer complexes, the intensity ratio of the dissociated CF3SO3- anions in the mixed anion polymer complexes shows negative deviations from ideality. The DLAM band of the polymer chains in the two polymer complex systems does not display any mixed cation or mixed anion effect.