Microstructures and structural properties of sol-gel silica foams

Berrier, Elise; Zoller, C.; Beclin, F.; Turrell, S.; Bouazaoui, M.; Capoen, Bruno

Type de document :

Compte-rendu et recension critique d'ouvrage

DOI :

10.1021/jp053089+

Titre :

Microstructures and structural properties of sol-gel silica foams

Auteur(s) :

Berrier, Elise [Auteur]

Laboratoire de Physique des Lasers, Atomes et Molécules - UMR 8523 [PhLAM]
Zoller, C. [Auteur]
Laboratoire de structures et propriétés de l'état solide - UMR 8008 [LSPES]
Beclin, F. [Auteur]
Laboratoire de structures et propriétés de l'état solide - UMR 8008 [LSPES]
Turrell, S. [Auteur]
Centre d'Etudes et de Recherches Lasers et Applications [CERLA]
Laboratoire Avancé de Spectroscopie pour les Intéractions la Réactivité et l'Environnement - UMR 8516 [LASIRE]
Bouazaoui, M. [Auteur correspondant]
Laboratoire de Physique des Lasers, Atomes et Molécules - UMR 8523 [PhLAM]
Capoen, Bruno [Auteur]

Laboratoire de Physique des Lasers, Atomes et Molécules - UMR 8523 [PhLAM]

Titre de la revue :

Journal of Physical Chemistry B

Pagination :

22799-22807

Éditeur :

American Chemical Society

Date de publication :

2005

ISSN :

1520-6106

Résumé en anglais : [en]

Silica xerogels were synthesized and annealed at 1000 °C for different durations to yield stable silica materials. The samples were prepared through base-catalyzed hydrolysis and condensation of tetramethyl orthosilicate ...
Lire la suite >Silica xerogels were synthesized and annealed at 1000 °C for different durations to yield stable silica materials. The samples were prepared through base-catalyzed hydrolysis and condensation of tetramethyl orthosilicate in methanol. After aging and drying steps, clear and solid xerogels exhibiting a narrow pore size distribution were achieved. The annealing treatment of these xerogels was performed at 1000 °C and proved in the present study to lead to a monolithic glass when a progressive heat-treatment procedure was employed to attain 1000 °C. In addition to the expected glass, silica foams and ordered phases were observed when the samples were instantaneously heat-treated at 1000 °C. Raman spectra of the foamed materials exhibit the classical features of amorphous silica, whereas transmission electronic microscopy pictures reveal the presence of crystallized domains within the vitreous matrix. These crystallites are prone to nucleation and growth processes, which jeopardize the believed stability of the silica foam. The assessment of the hydroxyl content by IR spectroscopy reveals the role played by the latter polycondensation of silanols. The occurrence of foaming process was thus found to result from two competitive phenomena occurring at 1000 °C: evacuation of water-related species and viscous sintering.Lire moins >

Langue :

Anglais

Vulgarisation :

Non

Collections :