Spectroscopic studies for molecular structure and complexation of silver polymer electrolytes

Polymer electrolytes containing silver ions have the potential to facilitat e transport in membranes for separating olefin/paraffin mixtures. In the pr esent study, the formation of AgBF4 and AgCF3SO3 complexes with poly(2-ethy l-2-oxazoline) (POZ) and poly(N-vinylpyrrolidone) (PVP) was investigated by spectroscopic methods. The carbonyl absorption bands of the infrared and R aman spectra of POZ and PVP with the silver salts confirm complex formation between silver ions and carbonyl oxygens. The symmetric stretching modes f or SO3 of AgCF3SO3 complexed with PVP were analyzed in terms of "free" anio ns, ion pairs, and higher-order ion aggregates. The results suggest that th e coordination number of silver ion with carbonyl oxygen of POZ and PVP is close to unity, demonstrating unusually high solubility of silver ions in t he POZ and PVP matrices. Above the solubility limit, the ion pair and highe r-order ion aggregates start to form.