Study of association in alkali metal perchlorate-poly(ethylene glycol) monomethyl ether solutions by FT-IR spectroscopy and conductivity measurements

The FT-IR spectra of LiClO4, NaClO4, KClO4, RbClO4 and CSCLO4 solutions in poly (ethylene glycol) monomethyl ether were studied in a wide temperature (-50 to +80 degrees C) and salt concentration ranging from 10(-3) to 5 mol/kg. The splitting of the v(4) band due to the (ClO4)-Cl-35 and (ClO4)-Cl-37 isotopomers as well as the salt aggregation is analyzed. The influence of the temperature and the salt concentration on. the polymer characteristic vibration is studied. It was found that the ion-polymer interactions strongly depend on the type of cation and decrease as the cation radius increases. The changes in the polymer spectral pattern allow us to assume that cations are preferably coordinated by hydroxyl groups. The effect of the interactions of alkali metal cations with ether oxygens is weaker and can be observed only at high salt concentrations. The influence of the type of the cation on the formation of polymer-salt complexes and ionic aggregates is also discussed. (c) 2005 Elsevier B.V. All rights reserved.