Editor’s column

A.I. Gorshkov, E.N. Gribanov
Orel State University named after I.S. Turgenev

Abstract: The features of the formation of morphology of thin aluminosilicate films obtained electrochemically on an aluminum substrate from aqueous solutions of sodium silicate and sodium hydroxide have been systematically studied by atomic force microscopy. The effect of stress on the shape and characteristic dimensions of the surface elements of aluminosilicate films is shown. Films synthesized at a lower voltage (8 V) are characterized by an amorphous surface consisting of globules whose size ranges from 500 nm to 2,5 microns, for samples obtained at a higher voltage (more than 16 V), parallelepipeds with linear dimensions of 150-250 nm act as are found to be structural elements. It is established that at the first stage of synthesis, the surface of the aluminum anode is etched, and the resulting cells act as pores in which the aluminosilicate phase is formed. An assumption is made about the formation of films along the path of autocatalytic nucleation and about a direct dependence of the rate of formation of the crystalline phase on the voltage at which the synthesis is carried out.
Keywords: synthetic aluminosilicates, growth mechanism, thin films, surface morphology, electrochemical synthesis

A.N. Bolotov, O.O. Novikova
Tver State Technical University

Abstract: Based on magnetic fluids, new effective technical devices have been implemented, such as magnetic fluid bearings, seals, and dampers. The magnetic-viscous effect inherent to magnetic fluids can not only improve the properties of magnetic fluid units, but significantly complicate their operation after a long stop. This refers to the so-called «stop effect», which occurs due to an abnormally high limiting shear stress in a nanostructured liquid. The plastic properties of the magnetic fluid are experimentally studied depending on the following parameters: shear stress, temperature, structure formation time. The destruction of the nanostructure of the magnetic fluid begins after the shear stress exceeds a certain critical value. At stresses below the critical, but above the limiting shear stress, the displacement of the solid surface occurs by overcoming the boundary friction of the magnetic fluid on the solid surface. The experimentally established exponential course of the temperature dependence of the shear rate reflects the nature of the forces that determine the internal friction in the magnetic fluid.
Keywords: magnetic fluid, yield strength, nanodispersed particles, magnetic interaction, chain model

A.N. Bolotov, L.E. Afanasieva, V.V. Meshkov
Tver State Technical University

Abstract: The paper presents the results of studying properties of magnetic lubricating oils synthesized on the basis of fluoroorganic fluids and triethanol. The lubricating properties of oils were determined in the boundary friction mode under medium and high contact pressures. It is shown that magnetic oils based on perfluoropolyether have higher lubricating properties than oils based on other fluids, especially in the medium load range. The anti-wear properties and aggregative stability of oil begin to deteriorate sharply at temperatures exceeding 150°С. The use of perfluoropolyether liquid as an additive to oil made it possible to improve the antiwear properties of magnetic oil at medium and high contact pressures. The lubricating properties of magnetic oils based on triethanolamine are approximately the same as those of magnetic oils based on siloxanes, but worse than those of traditional non-magnetic oils. In terms of tribological properties, the studied magnetic oils are comparable to traditional plastic and liquid lubricants. The fact that magnetic oils have magnetic properties that are anomalous for liquids expands the area of their effective application significantly.
Keywords: magnetic lubricating oil, fluoroorganic liquids, triethanolamine, nanodisperse particles, friction, wear

A.N. Bolotov, O.O. Novikova
Tver State Technical University

Abstract: In this paper, we studied the changes in the topography of the surface of a unit made of magnetostrictive magnetoplast under the influence of a magnetic field. Theoretical analysis has shown that in composite materials when using magnetostrictive particles with a dispersion of 10^-4÷10^-6 m, a change in the surface roughness parameters is possible in the range of 10^-7÷10^-9 m, depending on the magnetostrictive constants of the filler. Local changes in the topography of the magnetoplast surface in a magnetic field with a strength of about 560 kA/m are experimentally determined, and an assessment is made of the integral changes characterizing the surface as a whole. For the experiment, a composite material containing a powder of TeFe₂ material with a uniquely high linear magnetostriction (λ_s = 2∙10³) was chosen. It has been established that the effect of the surface nanoroughness changing is especially pronounced for relatively smooth surfaces and depends on the composition, concentration, size, and orientation of the microfine magnetic filler. For the studied surfaces of magnetoplasts, the change in the height parameters of roughness exceeds 5%. In absolute terms, the change in the topography of the surface is tens of nanometers. In precision engineering, the detected effect can be used to control frictional characteristics, in particular, to change the friction force without contact, control the flow of small doses of various reactive gases, and change the dynamics of wetting processes of solid surfaces.
Keywords: magnetostriction, magnetoplast, magnetic field, surface topography, surface roughness, composite material

E.A. Bogdanova¹, T.G. Khonina², N.A. Sabirzyanov^1
1 Institute of Solid State Chemistry of the Ural Branch of RAS
² I.Ya Postovsky Institute of Organic Synthesis Ural Branch of RAS

Abstract: The article discusses the possibility of practical application of hydroxyapatite and fluorapatite as components of medicines, pharmaceutical compositions and biomaterials, the use of which is based on the transdermal delivery route of the active substance. The viscosity, density, degree of dispersion and transport properties (transmucose permeability) of hydroxyapatite and fluorapatite were estimated using modern physicochemical methods of analysis. Particular attention is paid to the joint use of the studied substances and silicon glycerolates as a conductor with pronounced transcutaneous, penetrating properties, contributing to the accumulation of locally applied drugs in biological membranes (skin, mucosa, etc.) without disturbing its structure. It is shown that the transport properties that determine the effectiveness of the action depend on the physico-chemical characteristics of the substances being penetrated. Diffusion transfer and the ability to control the processes taking place can be used for optimal design of drugs for targeted delivery through the skin and mucous membranes.
Keywords: hydroxyapatite, fluorsubstituted hydroxyapatite; siliconglycerolatas; transmucosal permeability

E.A. Bogdanova, V.M. Skachkov
Institute of Solid State Chemistry of the Ural Branch of RAS

Abstract: The article discusses the possibility of obtaining a hardened composite material with a porous structure based on nanostructured hydroxyapatite (HAP) synthesized by precipitation from a solution. The new material by the mechanochemical synthesis of hydroxyapatite with aluminum, silicon, nickel, hafnium and titanium was obtained. The synthesized samples are certified using modern physico-chemical methods of analysis. The influence of the qualitative and quantitative composition of the composite on the sintering processes and the strength characteristics of the studied samples is shown. It has been experimentally established that the system Ca₁₀(PO₄)₆(OH)₂ – Ti is the most promising for the development of biocomposites based on it. Composite materials of this composition with the content of the doping component (10-20 wt.%), have a dense uniform structure with a high degree of crystallinity, with developed porosity, are a promising material for further research in order to introduce it into medical practice. A patent application has been filed for the developed composite material.
Keywords: hydroxyapatite, titanium, sintering, composite biomaterials, crystallinity, microhardness

A.N. Belov¹, N.V. Vostrov², G.N. Pestov¹, A.V. Solnyshkin^2
1 National Research University of Electronic Technology
² Tver State University

Abstract: This paper describes manufacturing the film structures based on a polar copolymer of poly(vinylidene fluoride-trifluoroethylene) P(VDF-TrFE) using the process of drop-by-drop local deposition on metallized substrates. The produced samples were a crossbar structures of arrays of ferroelectric P(VDF-TrFE) microislands metallized with nickel stripes using a combined 2D printing method. For the polymer layer deposition, a number of solvents with different viscosities and dipole moments of molecules were considered, and their influence on the geometry and the polar properties of printed layers was shown. Using the piezoelectric force microscopy, the value of the piezoelectric modulus of d₃₃ at the nanoscale level was determined. This d₃₃ modulus is similar to values of d₃₃ for P(VDF-TrFE) films produced by the standard solvent cast method. On the base of amplitude of the pyroelectric current in the dynamic method, the value of the pyroelectric coefficient (p) was determined, varying from 2⋅10^–5 to 4⋅10^–5 C/(m²⋅K). These values are comparable to the pyroelectric coefficient of films P (VDF-TrFE) produced by the standard method. The highest values of d₃₃ and p correspond to structures produced from solutions containing more than 20% of propylene carbonate in the initial solvent, the molecules of which have a large (4,9 D) dipole moment.
Keywords:

A.N. Belov¹, N.V. Vostrov², G.N. Pestov¹, A.V. Solnyshkin^2
1 National Research University of Electronic Technology
² Tver State University

Abstract: This work is devoted to the technological features of creating an array of pyroelectric nanoparticles placed in the pores of a silicon oxide membrane, ensuring their thermal insulation both from each other and from the supporting substrate. Mechanisms of anodic oxidation of the Al/Ti/SiO₂ structure, ensuring the self-organization of a nanostructured oxide mask with specified geometric parameters, have been established. It has been shown that from a certain thickness of the adhesion layer, overgrowing of the open areas of the mask with titanium oxide nanoparticles does not occur. The regularities of the method of local ion etching of multilayer structures are determined, which ensures control of the depth of the formed pores by controlling the ion current. A correlation has been established between the lateral size of the cavities in silicon and the aspect ratio of aluminum oxide pores. The possibility of forming a silicon oxide membrane with pyroelectric polymer nanoparticles embedded in its pores has been demonstrated.
Keywords: polymeric ferroelectric, porous silicon oxide, ion-beam etching, IR – photodetector ,porous anodic alumina, micromembrane, anisotropic etching

A.Yu. Ataeva
North Caucasian Institute of Mining and Metallurgy (State Technological University)

Abstract: The work is devoted to an experimental study of the behavior of bubbles when capturing pulverized materials with nanoparticles in the course of colliding of gas-liquid jets in a bubbling layer. The article discusses the use of channels in a jet bubbler and the dependence for detecting horizontal movement of bubbles with nanoparticles in them. The purpose of this stage of research is to study the behavior of gas-liquid jets when exiting without a guide channel and through a guide channel. The results of experiments conducted on the patented design of the jet bubbler are analyzed. The article presents the results of experiments conducted to study the shapes and sizes of formed gas bubbles. The graphs constructed after processing the frames of the kinogram according to the data of the experiments are given. On the basis of preliminary tests, the features of using channels to create the jet collisions in an experimental setup to increase the range of captured solid particles, including nanoparticles, are substantiated.
Keywords: ecosystem, dust and gas separator, nanoparticles, channel, wet dust collection, bubbling

A.A. Cherepovskaya, D.A. Ryzhkova
Katanov Khakass State University

Abstract: In this work, computer simulation of the processes of formation of the internal structure of plasmonic Ag-Cu nanoparticles was carried out. Method of molecular dynamics based on the tight binding potential was used. The crystallization of Ag-Cu nanoparticles with a diameter of 2,0-8,0 nm with an atomic copper content ranging from 10 to 50% was simulated. To remove thermal energy, an Andersen thermostat was used with three different cooling rates ΔT/Δt = 30∙10¹¹, 12∙10¹¹, 5∙10¹¹ K/s. The possible structural transitions arising in this case were determined using the radial distribution function and the change in potential energy. To determine the most stable cluster structure, an ensemble of nanoparticles of the same size was taken. Then, using the visualizers OVITO and xmakemol, the real appearance and structure of the studied nanoparticles were found. In the course of the simulation, it was found that at low levels of copper doping in Ag-Cu nanoparticles, the formation of five-particle symmetry is possible. The conditions for the occurrence of this effect were fixed. It was also determined that D = 8,0 nm for Ag-Cu nanoparticles is the size limit, starting from which the macroscopic effect of stabilizing the fcc structure of the eutectic alloy appears under the condition of very fast sample quenching.
Keywords: nanoclusters, silver, copper, crystallization, structure, computer simulation, tight binding