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In this work, the synthesis of Au nanoparticles stabilized with polyethyleneglycols with different molecular weights from 200 to 8000 Da was carried out. The synthesis was carried out by the method of chemical reduction in an aqueous medium using sodium citrate as a reducing agent. The dependence of the optical properties on the concentration and molar mass of polyethyleneglycol was studied in the obtained samples of Au nanoparticles. The absorption spectra were recorded using an SF-56 optical spectrometer. The studies were carried out in the visible range of the spectrum from 400 to 800 nm. It was found that the type of spectrum, the position of the surface plasmon resonance band and the optical density of the samples of Au nanoparticles stabilized with PEG-8000 with a concentration of 10 and 20% did not undergo significant changes during storage, which characterizes the high aggregate stability of these sols. The dispersed characteristics of these samples of sols of Au nanoparticles were also studied. The studies were carried out using photon-correlation spectroscopy by the method of dynamic light scattering. It is established that an increase in the concentration of the stabilizer leads to an increase in the average hydrodynamic radius of the particles. This fact is associated with an increase in the thickness of the stabilizer layer and with the "stitching" of the polymer layer of Au nanoparticles with the formation of aggregates. Thus, the best result was found in PEG-8000 samples with concentrations of 10 and 20%, since the type of spectrum, the position of the surface plasmon resonance band and the optical density did not undergo significant changes. Based on the data obtained, it can be concluded that the best stabilizer for Au nanoparticles obtained by the citrate method is PEG-8000 with a concentration of at least 10 %. It is important to note that with an increase in the concentration of the stabilizer, the average hydrodynamic radius of the particles increases. This fact is associated with an increase in the thickness of the stabilizer layer and with the "stitching" of Au nanoparticles.

In this work we have developed a nanoscale composite protective preparation for car paint and varnish coatings. We developed methods to obtain SiO2-TiO2, TiO2-ZrO2, SiO2-ZrO2 and SiO2-TiO2-ZrO2 nanocomposites, which are crystallization centers for the formation of a nanoscale composite protective coating with certain morphology and roughness. The phase composition of the samples and stability in alkaline media were studied. It is shown that SiO2-TiO2-ZrO2 nanocomposites with a content of titanium dioxide from 8%–9.5% and zirconium dioxide from 0.5%–2% exhibit complete insolubility in a highly alkaline medium, allow to form uniform structure on paint and varnish coatings, and protect the car surface from exposure to ultraviolet radiation. We determined the optimal composition of the preparation components for the formation of a nanoscale composite protective coating with hydrophobic properties and a wetting contact angle of more than 120 degrees: tetraethoxysilane ≤ 10 vol.%., titanium tetraisopropylate ≥ 2 vol.% and plant resin ≥ 8 vol.% Practical approval of the developed preparation on BMW X6 showed a pronounced hydrophobic effect. Evaluation of the stability of the nanoscale composite protective coating to the washing process showed that the developed preparation is able to maintain its hydrophobic properties for more than 150 washing cycles.

In this article, we presents the synthesis and research of a tool for removing metal inclusions from the surface of car paint coatings. The optimal composition of the product was determined, which includes sodium laureth sulfate, citric acid, sulfosalicylic acid, hydrogen peroxide and water. As a result of the conducted studies, a connection was established between the composition and the physicochemical, surface-active properties of the developed agent. Approbation of this tool was carried out, which confirmed its effectiveness and showed that within 30–45 s after applying the developed tool, not only are metal inclusions on the surface of car paint coating removed but also mineral contaminants in the form of sand, earth, clay and other particles. The aim of the work was to develop and optimize a method for obtaining a low-toxicity, highly effective agent for removing metal inclusions from the surface of car paint coatings and to investigate its effectiveness, as well as its physicochemical, optical and surface-active properties.