Role of polymer matrix in polymer/silver complexes for structure, interactions, and facilitated olefin transport

The role of the polymer matrix in facilitated olefin transport through polymer/silver salt complex membranes was investigated, particularly its influence on the structure and interactions of polymer/silver salt complexes and hence on the interactions of silver ions with olefin molecules. This role was assessed for complexes of silver salts with polymeric ligands containing three different carbonyl groups, specifically, amide, ketone, and ester groups. It was found that the threshold concentration of silver salt for facilitated olefin transport depends on the polymeric ligand and has the following order: amide > ketone > ester. This dependence of the threshold concentration on the polymeric ligand is explained in terms of the differences between the comparative strengths of the interactions of silver ions with the different carbonyl oxygens and that of silver ions with olefin molecules. It is concluded that when the former interaction is stronger than the latter, the threshold concentration for facilitated olefin transport is high, and when the former interaction is weaker than the latter, the threshold concentration for facilitated olefin transport is low. These interactions were characterized experimentally using differential scanning calorimetry, X-ray photoelectron spectroscopy, and FT-IR and Raman spectroscopy.