Morphological and textural control of spray-dried mesoporous silica-based spheres
- 14 May 2004
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in Journal of Materials Chemistry
- Vol. 14 (13), 2006-2016
- https://doi.org/10.1039/b403201b
Abstract
Micrometric ordered mesoporous silica spheres are synthesised by spray-drying alcoholic sols. For this synthetic route, the important effect of siloxane chemistry on both the morphological and the textural properties of spray-dried silica particles is demonstrated. This is achieved by correlating data obtained on the sols prior to atomisation (29Si liquid state NMR, SAXS) with data coming from a multi-scale characterisation of the resulting powders (SEM, XRD, 1H high resolution solid state NMR). The morphology (agglomerated or separated spheres, 1 to 3 µm of diameter) and texture (disordered or ordered p6mm mesophases), as well as the silica–surfactant interface, are sensitive to variations in the proportion of solvent or in the ageing time of the sols. These effects are related to the relative extents of siloxane hydrolysis and condensation reactions as evidenced by the variations in the radii of gyration of the siloxane oligomers, and in the remaining non-hydrolysed Si-OR alkoxy groups. We propose a scheme for the formation of the spray-dried mesoporous spheres that takes into account the main role of these reactions, and their effects on the determining physico-chemical processes: solid formation, fragmentation and aggregation of droplets, micellisation, mesophase formation and extension.Keywords
This publication has 92 references indexed in Scilit:
- Morphological Control of MCM-41 by Pseudomorphic SynthesisAngewandte Chemie International Edition, 2002
- “Smart” Glasses: Molecular Programming of Rapid Dynamic Responses in Organosilica Sol-GelsAdvanced Materials, 2002
- Spherical MSU-1 Mesoporous Silica Particles Tuned for HPLCAdvanced Functional Materials, 2001
- Micrometer-Sized Mesoporous Silica Spheres Grown under Static ConditionsChemistry of Materials, 1998
- Sol−Gel Synthesis of Organized MatterChemistry of Materials, 1997
- Alkaline Lyotropic Silicate−Surfactant Liquid CrystalsJournal of the American Chemical Society, 1997
- Kinetic and thermodynamic issues in the early stages of sol-gel processes using silicon alkoxidesCatalysis Today, 1997
- Nucleation Events during the Synthesis of Mesoporous Materials Using Liquid Crystalline TemplatingLangmuir, 1996
- Formation of Cagelike Intermediates from Nonrandom Cyclization during Acid-Catalyzed Sol-Gel Polymerization of Tetraethyl OrthosilicateMacromolecules, 1995
- Solid-state NMR study of ordered mesoporous aluminosilicate MCM-41 synthesized on a liquid-crystal templateSolid State Nuclear Magnetic Resonance, 1993