SPECTROSCOPIC STUDIES OF LUMINESCENT AND IONICALLY CONDUCTING EU[N(CF3SO2)(2)](3)-PPG4000 COMPLEXES

Alternating current impedance, Fourier transform Raman/infrared (IR), and luminescence excitation (continuous and time-resolved) measurement s have been conducted on solutions of poly(propylene glycol) (MW 4000) complexed with Eu[N(CF3SO2)(2)](3) salt, EuTFSI3, along with differen tial scanning calorimetry (DSC) studies. From observed frequency shift s of characteristic internal anionic vibrational modes (Raman and IR), we conclude that the salt is solvated by the polymer host. The TFSI a nions, however, interact extensively with Eu3+ cations at all concentr ations investigated. Ion-polymer interactions are manifested as change s in characteristic vibrational modes of the polymer. Continuous and t ime-resolved site-selective luminescence data give, respectively, evid ence for two different types of chemical environments for solvated Eu3 + cations. In particular, D-5(0)-F-7(0) transition exhibits a structur ed two-component the strongly forbidden nondegenerate profile in the s pectra. DSC data show that the lass transition temperature, T-g, is on ly marginally affected by the introduction of a relatively high concen tration of salt into the host matrix, whereas the resulting polymer-sa lt complex is of rubbery character, distinctly different from the pure host polymer, which is a viscous liquid at room temperature. The pres ent findings are interpreted in terms of a phase-segregated microstruc ture. This conjecture is supported by previous studies on PPG4000-base d electrolytes indicating microscopic phase anomalies. (C) 1998 Americ an Institute of Physics.