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Paris, M., Fritsch, E. & Reyes, B. A. O. (2007) H-1, Si-29 and Al-27 NMR study of the destabilization process of a paracrystalline opal from Mexico. J. Non-Cryst. Solids, 353 1650–1656.
Added by: Laurent Cournède (2016-03-10 22:02:30) |
| Type de référence: Article DOI: 10.1016/j.jnoncrysol.2006.12.111 Numéro d'identification (ISBN etc.): 0022-3093 Clé BibTeX: Paris2007 Voir tous les détails bibliographiques  |
Catégories: MIOPS Mots-clés: angle-spinning nmr, hydration, MAS NMR, MAS-NMR and NQR, NMR, nuclear-magnetic-resonance, rotating solids, short-range order, silica, Surface, Water Créateurs: Fritsch, Paris, Reyes Collection: J. Non-Cryst. Solids |
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This is the first NMR study of the destabilization through whitening of paracrystalline opal-CT (SiO2, nH(2)O). The aim of this study is to understand the process leading to the degradation, particularly any changes in the structure and bonding of this material. Si-29 and Al-27 NMR signals are not significantly modified. In contrast, using for the first time H-1 as a probe in opal, we show that a comprehensive understanding can be obtained on both the local structure of the opal-CT and the destabilization process. Thus, we propose the latter is related to some changes in 1H speciation (loss of strongly 'bound' water and appearance of new species) which induce structural reorganizations on the surface and in the rim of the silica nanograins constituting opal-CT. (C) 2007 Elsevier B.V. All rights reserved.
Added by: Laurent Cournède |