Influence of relative humidity and temperature on the sol-gel transition of a siloxane surface treatment

Abstract

This work investigates the effect of relative humidity (RH) and temperature on drying phenomenon of a siloxane coating during the sol-gel process. An experimental approach was taken, due to a lack of available data in existing literature. Dynamic Vapor Sorption, Fourier Transform Infra-Red spectroscopy and X-ray Photoelectron Spectroscopy analyses were performed during sol drying, while controlling RH and temperature. The drying time increased exponentially when RH was increased. This was linked to water uptake and evaporation rate decrease, forming a more condensed coating. The thermally activated process was fitted by the Arrhenius law with an activation energy of 41.7 kJ mol −1 . A double exponential law was proposed to describe the time needed for drying the sol as a function of temperature and RH. Finally, differences in the gel formed were clearly demonstrated. Between a RH of 30 and 50%, the gel formation turned from a dry-before-gel to a gelbefore-dry phenomenon, stressing the importance of temperature and RH control during the drying process of the sol.

Simple and Versatile Analytical Method for Monitoring the Deposition of Thin Layers by Optical Measurement and Calculation of Residual Stress

“…In this case, the sol-gel transition would therefore lie between 20 and 36 min. This value is consistent with the time found in our previous study [14] via the Dynamic Vapor Sorption test (i.e. 30 min at 22 ° C and 50% relative humidity).…”

“…The validity and quality of the results are discussed with the literature and previous results based on other characterization techniques [14]. This provides experimental data on the development of stress related to sol-gel and HiPIMS deposition processes.…”

“…Glycidyl 3-(trimethoxysilyl) propyl ether (GLYMO), zirconium (IV) tetra-1-propoxide (ZrTPO) were stirred in hydroalcoholic solution for one hour to create the sol. This solution was sprayed to the surface and dried in laboratory conditions (temperature of 22°C and relative humidity of 50%) as described previously [14].…”

“…This study therefore highlights the drying mechanism. This is dependent on ambient conditions of temperature and relative humidity, as highlighted by X-Ray photoelectron spectrometry measurements [14]. In laboratory conditions (22°C and 50% relative humidity), drying lasts 36 minutes leading to a low stressed gel suitable for anticorrosive applications.…”

Modelling and Optimisation of the Sol-Gel Conditions for Synthesis of Semi-Hexagonal Titania-Based Nano-Catalyst for Esterification Reaction

“…The effect of the interaction of gelling temperature and complex time on the conversion of oleic acid in the esterification reaction, with acid ratio and calcination temperature both constant at 1.5 and 150 • C, respectively, (Figure 4a) shows that increasing the gelling time to 75 • C causes an increase in the catalytic activity in the esterification reaction. It was also reported that the gelling temperature controls the rate of water evaporation from the precursor's mixture [46]. Less evaporation causes trapping of the water molecules into the metal oxide structure, and inhibits the bonding of metal cations.…”