Structure of hybrid organic–inorganic sols for the preparation of hydrothermally stable membranes

• Published in: Journal of sol-gel science and technology Vol. 48; no. 1-2; pp. 11 - 17
• Main Authors: Castricum, Hessel L., Sah, Ashima, Geenevasen, Jan A. J., Kreiter, Robert, Blank, Dave H. A., Vente, Jaap F., ten Elshof, Johan E.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Boston Springer US 01.11.2008; Springer; Springer Nature B.V
• Subjects: Catalysis; Ceramics; Chemistry; Chemistry and Materials Science; Colloidal gels. Colloidal sols; Colloidal state and disperse state; Composites; Condensation; Ethane; Exact sciences and technology; General and physical chemistry; Glass; Inorganic Chemistry; Materials Science; Membranes; Nanotechnology; Natural Materials; NMR; Nuclear magnetic resonance; Optical and Electronic Materials; Original Paper; Photon correlation spectroscopy; Porous materials; Precursors; Sols; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Thin films; Membrane; Polymeric sol; Hydrothermal stability; Microporous; Organic–inorganic hybrid; Silica; Water; Viscosity; Binary compound; Silica, Organic-inorganic hybrid; Hybrid material; NMR spectrometry; Condensation; Porous material; Precursor; Thin film; Synthesis; Dynamics; Defect; Chemical reactivity; Structure; Colloidal sol; Catalytic reaction; Membrane, Microporous; Stability; Light scattering; Colloid; Ethane; Hydrolysis; Liquid; Microporosity; Acids; Sol gel process; Preparation; Hydrothermal condition; Silane
• ISSN: 0928-0707; 1573-4846
• DOI: 10.1007/s10971-008-1742-z

A procedure for the preparation of hybrid sols for the synthesis of organic–inorganic microporous materials and thin film membranes is reported. We describe silane reactivity and sol structure for acid-catalysed colloidal sols from mixtures of either tetraethylorthosilicate (TEOS) and methyltriethoxysilane (MTES), or bis(triethoxysilyl)ethane (BTESE) and MTES. Early-stage hydrolysis and condensation rates of the individual silane precursors were followed with 29 Si liquid NMR and structural characteristics of more developed sols were studied with Dynamic Light Scattering. Condensation was found to proceed at more or less similar rates for the different precursors. Homogeneously mixed hybrid colloids can therefore be formed from precursor mixtures. The conditions of preparation under which clear sols with low viscosity could be formed from BTESE/MTES were determined. These sols were synthesised at moderate water/silane and acid/silane ratios and could be applied for the coating of defect-free microporous membranes for molecular separations under hydrothermal conditions.