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Cation coordination and hydrogen bonding in potassium and magnesium based-di-amidosil hybrids

S. C. Nunes ; V. D. Bermudez ; Denis Ostrovskii (Institutionen för teknisk fysik, Kondenserade materiens fysik) ; L. D. Carlos ; M. M. Silva ; M. J. Smith
Journal of Molecular Structure (0022-2860). Vol. 874 (2008), 1-3, p. 128-137.
[Artikel, refereegranskad vetenskaplig]

Fourier transform mid-infrared and Raman spectroscopies were employed to elucidate the cation/alkylene chains, cation/cross-link, cation/anion interactions and hydrogen bonding occurring in amorphous di-amide cross-linked alkylene/siloxane hybrid materials (diamidosils) doped with potassium and magnesium triflates (KCF3SO3 and Mg(CF3SO3)(2), respectively). Materials with compositions infinity > n >= 5 (where it expresses the molar ratio of carbonyl oxygen atoms per guest cation) were investigated. The conformations (gauche) of the alkylene chains of the host di-amidosil matrix are not affected by the presence of the guest salt in both doped di-amidosil families. The K+ and M2+ ions coordinate to the carbonyl oxygen atoms of the amide cross-links within the whole range of salt concentration considered, leading to the saturation of the cross-linkages, to a redistribution of the amide-amide hydrogen-bonded aggregates of the host matrix and, in the case of the K+-doped sample with n = 10, to the formation of a new type of aggregate, stronger and more ordered than those detected at lower salt content. In both di-amidosil systems guest salt addition leads to the increase of ionic associated species and to a concomitant decrease of the concentration of "free" anions. (c) 2007 Elsevier B.V. All rights reserved.

Nyckelord: sol-gel process, di-amidosils, magnesium and potassium triflates, FT-IR, FT-Raman, INFRARED TEMPERATURE, POLYMERS, ENVIRONMENT, BANDS

Denna post skapades 2009-10-27. Senast ändrad 2016-07-19.
CPL Pubid: 100854


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Institutionen för teknisk fysik, Kondenserade materiens fysik (1900-2015)


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