DLS and SAXS investigations of organic gels and aerogels
| Autor: | Cyrille Rochas, Patrick Achard, Anne-Marie Hecht, Nicolas Pinto, Gerard Pajonk, Sandrine Berthon, Françoise Bley, Erik Geissler, Frédéric Livet, Arnaud Rigacci, Françoise Ehrburger-Dolle, Olivier Barbieri |
|---|---|
| Přispěvatelé: | Centre Énergétique et Procédés (CEP), MINES ParisTech - École nationale supérieure des mines de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Institut de chimie des surfaces et interfaces de Mulhouse (ICSIM), Ecole Nationale Supérieure de Chimie de Mulhouse-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Spectrométrie Physique (LSP), Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de thermodynamique et physico-chimie métallurgiques (LTPCM), Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique de Grenoble (INPG), Laboratoire d'Application de la Chimie à l'Environnement (LACE), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS) |
| Rok vydání: | 2001 |
| Předmět: |
Gelation
X ray scattering 02 engineering and technology 010402 general chemistry 01 natural sciences Catalysis Acetone Colloid [SPI.ENERG]Engineering Sciences [physics]/domain_spi.energ Dynamic light scattering Formaldehyde Sol-gels Materials Chemistry Organic chemistry Drying Sol-gel Supercritical fluids Chemistry Small-angle X-ray scattering Agglomeration Percolation (solid state) Light scattering Water Aerogel 021001 nanoscience & nanotechnology Condensed Matter Physics Supercritical fluid 0104 chemical sciences Electronic Optical and Magnetic Materials Organic solvents Solvent Aging of materials Carbon dioxide Chemical engineering Alcohols Percolation Ceramics and Composites 0210 nano-technology |
| Zdroj: | Journal of Non-Crystalline Solids Journal of Non-Crystalline Solids, Elsevier, 2001, 285 (1-3), pp.Pages 154-161. ⟨10.1016/S0022-3093(01)00447-1⟩ |
| ISSN: | 0022-3093 |
| DOI: | 10.1016/s0022-3093(01)00447-1 |
| Popis: | 6th International Symposium on Aerogels (ISA-6) Albuquerque, New Mexico, October 08-11, 2000; International audience; Recent investigations have shown that the structure of organic aerogels can be significantly modified by changing the precursors, the solvent and the nature of the catalyst involved in the sol-gel reaction. It is therefore highly desirable to investigate the sol-gel mechanism. For this purpose, dynamic light scattering (DLS) measurements have been performed at different stages of the reaction for base- or acid-catalyzed gelation of resorcinol-formaldehyde (RF) using water or acetone as solvents. The structure of aged gels was investigated by small-angle X-ray scattering (SAXS) and compared to that of the aerogels obtained after exchange of solvent by supercritical CO2 and drying of the aged gels. It is shown that acid-catalyzed gelation of RF in acetone can be described by percolation, which explains that this series of aerogels consists of mass fractal aggregates (Dm = 2.5). The partial collapse of this polymeric gel yielding colloidal particles in the aerogel can be attributed to deswelling in supercritical CO2. DLS indicates that gelation of RF with a base catalyst yields a colloidal gel whose structure remains practically unchanged in the aerogel, as shown by SAXS. |
| Databáze: | OpenAIRE |
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