The in situ observation of a sol-to-gel transition in fast evaporating systems is a challenging task and the lack of a suitable experimental design, which includes the chemistry and the analytical method, has limited the observations. We synthesise an acidic sol, employing only tetraethylorthosilicate, SiCl4 as catalyst and deuterated water; the absence of water added to the sol allows us to follow the absorption from the external environment and the evaporation of deuterated water. The timeresolved data, obtained by total reflection infrared spectroscopy on an evaporating droplet, enables us to identify four different stages during evaporation. They are linked to specific hydrolysis and condensation rates that affect the uptake of water from external environment. The second stage is characterized by a decrease in hydroxyl content, a fast rise of condensation rate and an almost stationary absorption of water. This stage has been associated with the sol-to-gel transition

Sol to gel silica transition in fast evaporating systems observed by in situ time resolved infrared spectroscopy / Innocenzi, Plinio; Malfatti, Luca; Carboni, Davide; Takahashi, Masahide. - In: CHEMPHYSCHEM. - ISSN 1439-4235. - 16:9(2015), pp. 1933-1939. [10.1002/cphc.201500126]

Sol to gel silica transition in fast evaporating systems observed by in situ time resolved infrared spectroscopy

INNOCENZI, Plinio;MALFATTI, Luca;CARBONI, Davide;
2015-01-01

Abstract

The in situ observation of a sol-to-gel transition in fast evaporating systems is a challenging task and the lack of a suitable experimental design, which includes the chemistry and the analytical method, has limited the observations. We synthesise an acidic sol, employing only tetraethylorthosilicate, SiCl4 as catalyst and deuterated water; the absence of water added to the sol allows us to follow the absorption from the external environment and the evaporation of deuterated water. The timeresolved data, obtained by total reflection infrared spectroscopy on an evaporating droplet, enables us to identify four different stages during evaporation. They are linked to specific hydrolysis and condensation rates that affect the uptake of water from external environment. The second stage is characterized by a decrease in hydroxyl content, a fast rise of condensation rate and an almost stationary absorption of water. This stage has been associated with the sol-to-gel transition
2015
Sol to gel silica transition in fast evaporating systems observed by in situ time resolved infrared spectroscopy / Innocenzi, Plinio; Malfatti, Luca; Carboni, Davide; Takahashi, Masahide. - In: CHEMPHYSCHEM. - ISSN 1439-4235. - 16:9(2015), pp. 1933-1939. [10.1002/cphc.201500126]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11388/46081
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