Видання зареєстровані авторами шляхом самоархівування
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Item Atomistic modeling of formation and friction of materials with nanodimensional surfaces(Ivan Franko National University of Lviv, 2022) Хоменко, Олексій Віталійович; Хоменко, Алексей Витальевич; Khomenko, Oleksii Vitaliiovych; Захаров, Мирослав Владиславович; Захаров, Мирослав Владиславович; Zakharov, Myroslav Vladyslavovych; Gorpinchenko, M.O.The review presents the results of modeling of the solvation of nanoparticles with deep eutectic solvents that act as stabilizers of metal nanoparticles, which provide a new platform for nanoparticle technology. It is calculated that there is a slower dynamics of solvent molecules, i.e., a slowing down of water near solutes. Such water has limited movement and cannot be organized into tetrahedral forms, in contrast to water in volume. Also, the paper describes systematic studies of the adsorption configuration, distribution density and adsorption energy of molecules Н2О, CO2, CH4, N2, C8H18 and fluorocarbons C3F8 and C5F12 on the surface of kaolinite (001). Water adsorption is initiated and occurs due to the growth of clusters around surface groups, which is mainly regulated by the interactions of hydrogen bonds. Further, the paper investigates theoretically physical and mechanical properties of nanoscale systems, in particular, nanotips, amorphous carbon monolayer and nanoparticles. It is shown that the single-layer amorphous carbon is surprisingly stable and is deformed with a high ultimate strength without the propagation of cracks from the point of failure. The sliding on amorphous polyethylene and silicon studied using the method of molecular dynamics is described. The paper also discusses the dependencies of the friction force, acting on nanoparticles, on their velocity and sizes, in particular, the contact area, the structure and the type of the material, as well as on the direction of their shear and temperature. At an angle of rotation $ 45^\circ $, the silicon friction forces reach a minimum value, which can be termed superlubricity. The molecular dynamics modeling of the surface of carbon nanotubes, chitosan, polyvinyl acetate, titanium dioxide, α-quartz and zeolite is described to solve application problems ranging from reaction control to targeted delivery and creation of new drugs. The general principles have been identified that artificial water channels made of carbon nanotubes porins must satisfy, which can serve as a basis for further experiments. The organic modification mainly forms a modifier layer by crosslinking the hydrogen bond with the substrate, the flatness of the modified layer is strongly influenced by the type and concentration of the modifier.Item Atomistic modelling of frictional anisotropy of palladium nanoparticles on graphene(Institute for Condensed Matter Physics of the National Academy of Sciences of Ukraine, 2021) Хоменко, Олексій Віталійович; Хоменко, Алексей Витальевич; Khomenko, Oleksii Vitaliiovych; Захаров, Мирослав Владиславович; Захаров, Мирослав Владиславович; Zakharov, Myroslav VladyslavovychThis article is a continuation of our previous studies of the frictional anisotropy of metal nanoparticles on the surface of a graphene substrate for other temperature conditions. The friction force acting on palladium nanoparticles on a graphene sheet in various lateral directions is investigated using classical molecular dynamics modelling. Anisotropy is studied at high sliding speeds of nanoparticles consisting of 10000 atoms on the surface of graphene. The effect of incommensurability and short-range order of the contact surfaces of nanoparticles, as well as the graphene deformation lead to the absence of an expressed angular dependence of the friction force.Item Modification of ultrafiltration polymeric membranes with dispersed oxide nanoparticles(Ukrainian State University of Chemical Technology, 2020) Rozhdestvenska, L.M.; V’yunov, O.I.; Пономарьова, Людмила Миколаївна; Пономарёва, Людмила Николаевна; Ponomarova, Liudmyla Mykolaivna; Bilduykevich, A.V.; Plisko, T.V.; Zmievskii, Y.G.; Ivchenko, V.D.Organic-inorganic membranes containing the nanoparticles of hydrated zirconium dioxide and BaFe12O19 magnetic nanoparticles were prepared. The nanoparticles were inserted into polymer matrices. Ultrafiltration membranes were used as a polymer substrate. These materials consist of macroporous layer (non-woven polyester) and ultrathin active layer (polysulfone or polyacrylonitrile). Morphology of the membranes was investigated using scanning electron microscopy. It was established that inorganic nanoparticles form aggregates, a size of which is up to 20 nm in active layer and up to 2 m in macroporous fibrous support. Larger aggregates are formed in the absence of a magnetic constituent (up to 5 m). Fractal analysis showed the diffusion-limited aggregation model of particle formation. The inorganic particles form a «secondary active layer» inside the polymer pores: this layer determines water flux and rejection ability of the membrane. A thinner «secondary active layer» is formed in the polymer matrix containing smaller pores. The prepared membranes were tested for filtration of sugar beet juice. The modification was shown to improve the ability of the membranes to reject proteins. Due to smaller particle size, the membrane containing BaFe12O19 shows the liquid flux of 4.310–7–5.710–7 m3m–2s –1 at 2 bar and the rejection towards vegetable protein of 55–87%. Regarding the membranes that do not include magnetic nanoparticles, these values are 3.810–7–5.510–7 m3m–2s –1 and 38–77%, respectively.