BINDING OF ELECTROLYTES TO POLY(ETHYLENE OXIDE) IN AQUEOUS-SOLUTIONS

Ion selective electrode and ultrafiltration measurements have been employed to investigate the extent of electrolyte binding to poly(ethylene oxide) in aqueous solution. Although lithium chloride does not interact measurably with the polymer, significant binding is verified for sodium, potassium, rubidium, and cesium chlorides and for a series of other potassium salts. For the chlorides, operational binding constants, whose magnitudes depend on electrolyte and polymer concentrations, follow the sequence lithium << sodium < rubidium ≈ potassium ≈ cesium. These results are consistent with primary association of the alkali- metal cation with the polymer chain, creating a net positive potential that attracts the anions electrostatically to the vicinity of the polymer molecule. © 1990, American Chemical Society. All rights reserved.