OctTES/TEOS system for hybrid coatings: real-time monitoring of the hydrolysis and condensation by Raman spectroscopy

Abstract

The hybrid organic–inorganic system Tetra‐ethyl‐ortho‐silicate functionalized with Octyl‐triethoxy‐silane, studied as protective coating for the preservation of historical glasses from the environmental weathering agents, has been characterized by Raman spectroscopy by monitoring the sol‐gel reactions over time through characteristic features in the spectrum. In particular, for the hydrolysis reaction the disappearance of the 653 cm−1 (Si‐O symmetric breathing) and 810 cm−1 (CH2 rocking in Si‐alkoxides) peaks and the growth of the 710 cm−1 band, because of hydrolyzed alkyl‐silane, and of the 881 cm−1 peak (ethanol C–C symmetric stretching) have been checked. Moreover, the condensation reaction can be tracked by the disappearance of the two main peaks of the alcohols at 816 and 881 cm−1, going along with the growth of the broad band between 250 and 500 cm−1 (Si–O–Si symmetric bending) and of the feature at 840 cm−1 (Si–O–Si stretching). At the end of the condensation process the Raman spectrum still displays spectral bands unique to the alkyl chain in Octyl‐triethoxy‐silane, in the 1330–1450 cm−1 and 2725–3000 cm−1 ranges. Copyright © 2016 John Wiley & Sons, Ltd.

Kinetics of Alkoxysilanes and Organoalkoxysilanes Polymerization: A Review

“…Different catalysts, such as ammonia, were used to improve the polymerization process to prepare monodisperse nanoparticles (Stöber method) [36,42,43,50,51,52]. Mineral acids, such as HCl [30,37,53,54,55,56,57,58], phosphoric acid [38], and hydrofluoric acid [59], as well as organic acids, such as acetic acid [2,23,26,45,60,61,62,63], chloroacetic acid [24], p -toluene sulphonic acid [22], and methane sulphonic acid [21], were also used. Researches also looked at the use of other organic compounds, such as tin alkyl esters [24,28], while boron-based catalysts were used to overcome the toxicity of the tin compounds.…”

Thickness Characterization Toolbox for Transparent Protective Coatings on Polymer Substrates

“…Keeping industrial upscaling in mind, one must be able to produce a coating precursor in a relatively short time-span, which can be conserved for longer times. Raman spectroscopy has proven to be a valuable technique to monitor the condensation species of silicon-based sol-gel reactions [ 28 , 29 , 30 ]. This technique was used to follow the condensation reaction over time.…”

Recent advances in linear and non‐linear Raman spectroscopy. Part XI

“…de Ferri et al used the hybrid organic‐inorganic system tetra‐ethyl‐ortho‐silicate functionalized with octyltriethoxysilane as a protective coating for the preservation of historical glasses from environmental weathering agents. This coating has been characterized by Raman spectroscopy by monitoring the sol–gel reactions over time through characteristic features in the spectrum . Franca de Sa and co‐workers have provided new insight into polyurethane foam deterioration through the use of Raman microscopy for the evaluation of long‐term storage conditions.…”

“…This coating has been characterized by Raman spectroscopy by monitoring the sol-gel reactions over time through characteristic features in the spectrum. [178] Franca de Sa and co-workers have provided new insight into polyurethane foam deterioration through the use of Raman microscopy for the evaluation of long-term storage conditions. They found that open-air storage proved to be the most harmful condition, while anoxic storage showed the best results.…”