This article proposes a method for silver nanoparticle (AgNP) stabilization in polymer coatings obtained from aqueous acrylic dispersions. The main objective of the study was to improve the biocidal properties of coatings using AgNPs due to the preservation of their nanoscale state. Two types of AgNP solutions with fundamentally different stabilization mechanisms were synthesized and compared. Two mechanisms were determined: an aqueous electrostatic mechanism with sodium docusate stabilizer (AOT) and a steric, propylene glycol with polyvinylpyrrolidone (PVP) stabilizer. The results showed that both solutions were unstable and prone to precipitation as early as the first day after synthesis. However, the saturation of the propylene glycol AgNP solution with ammonium hydroxide to pH < 9 allowed the strengthening of the electrostatic factor of aggregative stability, providing optimal conditions for mixing with acrylic dispersions stabilized by anionic surfactants. The obtained AgNPs in the acrylic dispersions stabilized over time, and when they became film-forming, stable AgNPs (~20-30 nm) occurred on the surface. As a result, the developed coatings using AgNPs synthesized in propylene glycol in the presence of non-ionic PVP and modified with ammonium hydroxide, demonstrated a high inactivation of bacteria colony-forming units (CFU) (> 60%) within 60 min of contact compared to aqueous AgNP solutions using anionic surfactants as stabilizers, where the decrease in CFU was around 25%.
The paper presents the process of sol-gel synthesis of titanium dioxide nanoparticles, the peculiarities of the influence of component composition (titanium precursor content, solvent and stabilizer − surfactant) on the properties of sol and powder obtained on its basis. As a result of the study, the nature of the influence of the type and content of the surfactant in the solution of tetrabutoxytitanium in ethanol on the size of the synthesized particles of titanium dioxide was revealed. The optimal composition of the reaction mixture of TiO–R sol was obtained and the optimal ratio of tetrabutoxytitanium and ethyl alcohol was revealed using which a material with a high content of nanosized titanium dioxide was obtained.
The existing methods of confering hydrophobic properties to various building materials are considered. Obtaining special, including hydrophobic, properties of water-emulsion paints is a very relevant task. Previously, a method was developed for producing an emulsion of a polysiloxane stabilized with polyvinyl alcohol. The paper describes the possibility of using a hydrophobisating emulsion of polyhydrosiloxane as a functional additive for an acrylic water-dispersion paint. This emulsion is capable of forming coatings on dense and porous surfaces with an adjustable contact angle up to 105 °. The use of this emulsion, with its sufficient coalescence for volumetric hydrophobization of coatings, makes it possible to obtain a high contact angle on the surface. In the paper, it was assumed that the partial introduction of small amounts (up to 10 %) of a hydrophobizing emulsion into water-dispersion paints would allow achieving the contact angle of wetting for similar coatings consisting exclusively of emulsion. It is shown that the introduction of small amounts of a hydrophobizing emulsion with an auxiliary coalescing action of ethylene glycol makes it possible to impart hydrophobic properties to the surface of the resulting coating. When the optimum concentration of ethylene glycol in the coating is reached, dissolution and transport (yield) of polysiloxane to the surface is ensured. The research carried out made it possible to develop a paint composition with a hydrophobizing emulsion with a contact wetting angle of about 100 °, which ensured the hydrophobicity of the previously hydrophilic coating of a water-dispersion acrylic paint.
The article deals with the method for obtaining aqueous solutions of silica nanoparticles based on sol-gel technology, namely, products of hydrolysis of silicon alkoxides and their polycondensation in an alcohol medium. In order to prevent polymorphic changes and dehydration of SiOH-groups, preference was given to low-temperature and vacuum methods. To combat the excessive foaming ability of surfactants and replace the solvent (alcohol with water), a method of distillation was proposed for partial supply of dry steam with air and water. To separate aqueous surfactant solution (tween-80), a method of oil flotation with petroleum ether addition, characterized by its low solubility, both in water and in alcohol, was proposed. The specifications of obtained nanosilica of aqueous solutions can be estimated using optical spectrophotometry, for which the concentration and size coefficients of the Geller Equation for this system were determined. The optimum concentration of SiO2 in the system was also determined when no particles above 100 nm were formed. Methods for the reagents reuse of ethanol, petroleum ether and tween-80 were proposed.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.