Functionalization of mineral powders by condensation of reagents with low surface energy from the vapor phase

Conditions have been investigated and methodical techniques have been developed for functionalization of micro-, nanopowders of aerosil, titanium dioxide and diatomaceous earth based on vapor phase condensation of agents with low surface energy (tetraethoxysilane and stearic acid) in order to give them phobno/philic properties, as one of the requirements for creating materials or coatings with bulk superhydrophobicity Using IR spectroscopy, derivatography, scanning electron microscopy and x-metry, the mechanism of interaction of hydrophobic agents with the surface of the above powders and changes in their properties were investigated as a result of hydrophobization. Suspensions of functionalized powders in fluorinated lacquer were used for hydrophobization of various substrates: glass, aluminum, steel, fabrics and papers). The highest value of the marginal angle of wetting with water (170°) was achieved for coatings on aluminum obtained using a composition containing functionalized aerosil. Superhydrophobic coatings on the surface of steel, aluminum and glass with a marginal wetting angle in the range of 150–170° and a rolling angle of less than 10°, paper and fabric with volumetric hydrophobicity (150–170°) were obtained, retaining this property under normal operating conditions for at least 6 months and at elevated relative humidity (more than 80 %) for at least 1 month.

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