Fatures of the technology for obtaining hydrolysates of tetraethoxysilanes for various functional purposes
DOI:
https://doi.org/10.33216/1998-7927-2026-300-2-96-106Keywords:
sol-gel process, tetraethoxysilane, coatings, hydrolysis, polycondensationAbstract
The relevance of studying tetraethoxysilane hydrolysates is due to their wide range of applications in the creation of functional inorganic and hybrid materials with controlled properties, which are used in materials science, construction, medicine, energy, and protective technologies. The paper summarizes the features of obtaining tetraethoxysilane hydrolysates in the sol-gel process and analyzes the main technological parameters that determine their physicochemical stability and functional purpose. The mechanisms of hydrolysis and polycondensation of ethyl silicate in acidic and alkaline environments, as well as their influence on the formation of the siloxane structure of the sol, are considered. It is shown that the ratio of hydrolysis and condensation rates significantly depends on the pH of the environment: in an acidic environment, hydrolysis prevails over condensation, which contributes to the formation of homogeneous transparent sols, while in an alkaline environment, condensation intensifies and rapid formation of a spatially cross-linked siloxane network and particle enlargement occurs. The influence of the molar ratio of H₂O/TEOS, the type of catalyst, the nature of the solvent, the synthesis temperature, and the stirring conditions on the reaction kinetics and stability of the system was analyzed. It has been established that the optimal values of the synthesis parameters allow control of the particle morphology, the degree of siloxane network cross-linking, and the rheological properties of the hydrolysates. Particular attention is paid to the differences between TEOS and ethyl silicate-40, which determine their application in laboratory and industrial technologies. It is shown that control of the sol composition and hydrolysis conditions makes it possible to regulate the properties of the final materials and expand their areas of application. The modern directions of application of TEOS hydrolysates are summarized, in particular in the formation of protective and anti-corrosion coatings, the synthesis of silica nanoparticles, aerogels, functional textile materials, fibers, and composite systems. The main problems associated with increasing the stability of sols, restrictions on use, reproducibility of results, and optimization of sol-gel synthesis technological modes are identified. The prospects for further research are substantiated.
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