Ionic environment and hydrogen bonding in di-ureasil ormolytes doped with lithium triflate

Di-urea cross-linked sol-gel derived poly(oxyethylene) (POE)/siloxane hybrids (di-ureasils) doped with a wide concentration range of lithium triflate (LiCF(3)SO(3)) were studied by infrared and Raman spectroscopies with the primary objective of examining in detail the Li(+)/cross-link and hydrogen bonding interactions. Another goal of this work was to find additional data that confirmed previous conclusions regarding the Li(+)/polymer and Li(+)/anion bonding. Xerogels with infinity > n greater than or equal to 1 (where n, called salt composition, is the molar ratio OCH(2)CH(2)/Li(+)) were analyzed. The analysis of the 'amide I' and 'amide II' regions provided solid evidences that the Li(+) ions bond to the urea carbonyl oxygen atoms in the entire range of salt concentration studied. The changes detected in the CH(2) rocking region indicate that the alkali metal cations are also coordinated to the ether oxygen atoms of the POE chains at n less than or equal to 20. Proofs of the formation of a POE/LiCF(3)SO(3) crystalline compound at n :5 10 were also found. The anionic configurations detected in the FT-IR SO(3) symmetric stretching region are in perfect agreement with those deduced from the FT-Raman spectra. (C) 2004 Published by Elsevier B.V.