A 29Si and 13C CP/MAS NMR Study on the Surface Species of Gas-Phase-Deposited γ-Aminopropylalkoxysilanes on Heat-Treated Silica
| Autor: | Eero Iiskola, Satu Ek, Andrew Root, Tuula T. Pakkanen, Lauri Niinistö, Jari Vaittinen |
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| Rok vydání: | 2004 |
| Předmět: | |
| Zdroj: | The Journal of Physical Chemistry B. 108:11454-11463 |
| ISSN: | 1520-5207 1520-6106 |
| DOI: | 10.1021/jp048927z |
| Popis: | The aim of the present solid-state NMR study was to characterize the surface species of γ-aminopropyltriethoxysilane (APTS), γ-aminopropyltrimethoxysilane (APTMS), and γ-aminopropyldiethoxymethylsilane (APDMS) on porous silica when the deposition was performed via the gas phase. The reaction temperature used, that is, 150−300 °C, in an atomic layer deposition reactor at a pressure of 20−50 mbar, was observed to distinctly affect the surface species of aminopropylalkoxysilanes on silica. The gas−solid reactions of the precursors with the silica surface were observed to be surface-limiting at the deposition temperatures of ≤150 °C. On the basis of 29Si CP/MAS NMR, the amino ends of APTS and APTMS molecules were observed to react both with alkoxy groups of other precursor molecules and silanols of silica at deposition temperatures of ≥150 °C forming Si−N linkages. The amino groups of APDMS molecules were observed to react at 150 °C only on silica heat-treated at 200 °C in a similar way. The reaction of amino... |
| Databáze: | OpenAIRE |
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