کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1524545 | 1511832 | 2011 | 9 صفحه PDF | دانلود رایگان |
In the present work Fourier transform infrared and Raman spectroscopy were used to characterize the cation/polymer, cation/cross-link, cation/anion and hydrogen bonding interactions in hybrid electrolytes composed of lithium tetrafluoroborate (LiBF4) and di-urea cross-linked poly(oxyethylene) (POE)/siloxane hybrid networks (di-ureasils) designated as d-U(2000) and d-U(600) and incorporating polyether chains with ca. 40.5 and 8.5 oxyethylene repeat units, respectively. Samples with ∞ > n ≥ 2.5 (where n, composition, is the molar ratio of CH2CH2O units per Li+ ion) were analyzed. In both di-ureasil systems over the whole range of salt content examined the Li+ ions bond to the ether oxygen atoms of amorphous POE chains and to BF4− ions forming ion contact pairs. Spectroscopic evidences and SEM images confirm the presence of a crystalline POE/LiBF4 complex of unknown stoichiometry at n < 20 and 25, respectively. Ionic association is particularly important in the case of the d-U(600)-based materials, as a result of the presence of strong hydrogen-bonded aggregates that prevent the establishment of Li+/urea carbonyl oxygen atom interactions.
► FT-IR and FT-Raman spectroscopy were used to characterize cation interactions in two LiBF4-doped di-ureasil networks incorporating POE chains with different length.
► Over the range of salt content analyzed the cations bond to amorphous POE chains and form ion contact pairs with BF4−.
► A crystalline POE/LiBF4 complex of unknown stoichiometry emerges at high salt concentration.
Journal: Materials Chemistry and Physics - Volume 129, Issues 1–2, 15 September 2011, Pages 385–393