Low-temperature reaction of trialkoxysilanes on silica gel: a mild and controlled method for modifying silica surfaces

Autor: H. Cardy, Eve Péré, Sylvie Lacombe, Virginie Latour
Přispěvatelé: Institut des sciences analytiques et de physico-chimie pour l'environnement et les materiaux (IPREM), Université de Pau et des Pays de l'Adour (UPPA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)
Rok vydání: 2005
Předmět:
Zdroj: Journal of Colloid and Interface Science
Journal of Colloid and Interface Science, Elsevier, 2005, 281 (2), pp.410--416. ⟨10.1016/j.jcis.2004.08.061⟩
ISSN: 0021-9797
1095-7103
DOI: 10.1016/j.jcis.2004.08.061
Popis: International audience; The room temperature reaction of 4-(triethoxysilyl)butyronitrile, 4-TBN ((C 2H 5O) 3Si(CH 2) 3CN), on weakly hydrated silica samples pretreated at 393 K has been studied by desorption experiments and by diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy at different aging times under various water partial pressures. The reaction is demonstrated by the decrease of desorption of 4-TBN with time and the simultaneous disappearance of the 2980 and 1394 cm -1 signals in the DRIFT spectra, assigned to the CH 3 moiety of the ethoxy functions. Water partial pressure is shown to have a crucial effect on the rate and efficiency of the process as, after 6 days, for samples kept at room temperature under vacuum, ca. 50% of the silane has reacted, while for those kept in a water-saturated atmosphere the silane reaction reaches 96%. Although the silane appears to be irreversibly bonded to the surface, no definite conclusion may be drawn from these preliminary results as to the nature of the bonding (grafting or coating). These samples are compared to modified silicas prepared according to conventional methods. The same extent of silane reaction (50%) is achieved for preadsorbed samples kept under vacuum and either cured at 473 K for 30 h or kept at room temperature for 6 days. A mild and controlled modification of silica by triethoxysilanes can thus be achieved by first physisorbing known amounts of the modifying silanes from an organic solvent on pretreated silica and then letting the samples mature for a few days at room temperature in a water-saturated atmosphere. © 2004 Elsevier Inc. All rights reserved.
Databáze: OpenAIRE
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