Ionic environment and hydrogen bonding in di-ureasil ormolytes doped with lithium triflate
✍ Scribed by S.C Nunes; V.de Zea Bermudez; D Ostrovskii; L.D Carlos
- Publisher
- Elsevier Science
- Year
- 2004
- Tongue
- English
- Weight
- 318 KB
- Volume
- 702
- Category
- Article
- ISSN
- 0022-2860
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✦ Synopsis
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 þ /cross-link and hydrogen bonding interactions. Another goal of this work was to find additional data that confirmed previous conclusions regarding the Li þ /polymer and Li þ /anion bonding. Xerogels with 1 . n $ 1 (where n; called salt composition, is the molar ratio OCH 2 CH 2 /Li þ ) were analyzed.
The analysis of the 'amide I' and 'amide II' regions provided solid evidences that the Li þ 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 # 20: Proofs of the formation of a POE/LiCF 3 SO 3 crystalline compound at n # 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.