Mechanical properties of silica aerogels controlled by synthesis parameters

• Published in: Journal of non-crystalline solids Vol. 606; p. 122171
• Main Authors: Babiarczuk, Bartosz, Lewandowski, Daniel, Kierzek, Krzysztof, Detyna, Jerzy, Jones, Walis, Kaleta, Jerzy, Krzak, Justyna
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15-04-2023
• Subjects: Catalyst; Mechanical properties; Precursor concentration; Silica aerogel; Solvent; Mechanical properties; Silica aerogel; Precursor concentration; Solvent; Catalyst
• ISSN: 0022-3093; 1873-4812
• DOI: 10.1016/j.jnoncrysol.2023.122171

•Gelation time of sol-gel materials is firmly dependent on synthesis parameters.•Synthesis conditions control the structural properties of native SiO2 aerogels.•SiO2 network structure reflect in the mechanical nature of both gels and aerogels.•Elasticity of aerogels can be changed by density and also mass spatial distribution.•Catalyst influences the Young's modulus strongly but without changes in density.
Development of silica aerogels for real applications requires control of their mechanical properties. Based on the sol-gel procedure and using the alkoxide precursor of silica (TMOS), native silica aerogels were synthesized. This work explores the influence of three synthesis parameters, namely, TMOS concentration, catalyst concentration, and solvents (MeOH, EtOH, IPA), on the gel point, shrinkage and mechanical properties of aerogels. Structural studies were conducted to determine how the analysed synthesis parameters influenced the spatial network of aerogels and their elasticity. The analysis of the relationship between Young's modulus (E) and bulk density (ρ), E∝ρα, showed that the catalyst concentration appeared the most interesting parameter because, while the ρ did not change with an increase in the catalyst concentration, there was a significant increase in the E. We associate this observation with an increase in specific surface area, reflecting an increase in bond diameter between secondary particles formed in the aerogel.
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