[en] The microstructure of hybrid silica xerogels synthesized by the base-catalyzed polymerization of tetraethoxysilane (TEOS) in ethanol in the presence of 3-aminopropyltriethoxysilane (AES) and of 3-(2-aminoethylamino)- propyltrimethoxysilane (EDAS) as co-reactants, and dried in subcritical conditions, is analyzed. A thorough structural characterization of the samples is performed combining nitrogen adsorption, small-angle X-ray scattering (SAXS), and transmission electron microscopy coupled with digital image analysis. The use of these methods shows that, for both co-reactants, the xerogels are made of macropores supported by filaments, with each filament being formed of smaller structures. The quantitative impact of the additive on each structural level is assessed. The data are compared with a previous time-resolved SAXS study conducted during the formation of the gels (J. Phys. Chem. B 2004, 108, 8983-8991). The results are analyzed in the framework of a double phase separation model.
Disciplines :
Materials science & engineering Chemistry
Author, co-author :
Gommes, Cédric ; Université de Liège - ULiège > Département de chimie appliquée > Génie chimique - Génie catalytique
Basiura, Monika
Goderis, Bart
Pirard, Jean-Paul ; Université de Liège - ULiège > Département de chimie appliquée > Génie chimique - Génie catalytique
Blacher, Silvia ; Université de Liège - ULiège > Département des sciences cliniques > Labo de biologie des tumeurs et du développement
Language :
English
Title :
Structure of Silica Xerogels Synthesized with Organoalkoxysilane Co-reactants Hints at Multiple Phase Separation
Publication date :
2006
Journal title :
Journal of Physical Chemistry B
ISSN :
1520-6106
eISSN :
1520-5207
Publisher :
American Chemical Society, Washington, United States - District of Columbia
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