Vol 97, No 1 (2023)

A review is presented of the authors’ own works on what they believe are the most important features of the model proposed by N.A. Bulienkov for parametric non-crystallographic structures of water associated with biopolymers. Characteristics of the internal parameters of bound water with a globular protein are considered, and the existence of twist baths in the structure of bound water is confirmed. The nature of water bonding with monosaccharides is analyzed. It is shown they complement parametric structures much more than they do the crystal structure of ice Ih. Important features of parametric structures include the possible formation of enantiomorphic structures and the accumulation of elastic stresses that can be used in the mechanochemical processes of molecular machines.

Model structural mechanisms of transitions between crystalline water ices II → Ic, IV → Ic, and V → Ic are proposed. It is established that in the proposed II → Ic transition mechanism, one of the three systems of infinite parallel chains consisting of adjacent hexacycles and running along the 〈0001〉 direction of ice II is preserved, and these chains become parallel to one of the 〈211〉 directions of ice Ic. The proposed mechanism of the V → Ic transition preserves both systems of infinite parallel chains of adjacent hexacycles extended along the [101] and [10–1] directions of ice V; in ice Ic, they run along two directions 〈211〉 parallel to the same {120} plane. According to the proposed mechanism of the IV → Ic transition, puckered surfaces of hexacycles are retained. In all three cases, 3/4 of all hydrogen bonds are retained during the transition, and 1/4 of the bonds are rearranged. It is shown that the structures of ices II, IV, and V consist of the same structural element, which is slightly modified in ice V.

The author considers the main principles of Bulienkov’s simplicial-modular design of metal clusters (face-centered cubic (FCC), body-centered cubic (BCC), hexagonal close-packed (HCP) metals). Models of clusters are presented along with algorithms for their construction based on operations of twinning (1¯1¯, 2, m) to simplices and modules of the corresponding metals.

Phase equilibria in Ag–In–Pd ternary system were studied using Scanning electron microscopy, Energy-dispersive X-ray spectroscopy (EDX) and X-Ray diffraction method (XRD). The solubilities of the third components in Ag–In and In–Pd binary phases were established, as well as composition ranges (from 4 to 17.5 at % Ag at 25 at % In) and crystal structure of τ ternary compound (Al3Ti). New thermodynamic assessment of Ag–In–Pd ternary system was performed, basing on the published experimental data and those obtained in the present work. Good agreement was achieved between the calculation results and the experimental data on phase equilibria and thermodynamic properties of the phases. The results of the calculation reproduce well experimental DTA/DSC data of three samples (the data were not included into the optimization). This additionally supports the correctness of the obtained thermodynamic description.

A study is performed of the interaction between 2(4)-aminopyridines (2(4)-AP) and Pd(II), Pt(II), Pt(IV) and accompanying ions Ni(II), Co(II), Fe(II, III), Cu(II) in aqueous solutions close to the conditions of their extraction isolation and separation. It is shown that platinum metal ions form stable neutral and cationic complexes with both 2-AP and 4-AP that can be isolated from aqueous solutions. The tendency to form cationic complexes diminishes in the order Pd(II) > Pt(II) > Pt(IV) and 4-AP > 2-AP. With the exception of Cu(II), ions of 3d-elements do not form stable complexes under these conditions. Cu(II) forms complexes with 2(4)-AP that are subject to hydrolysis when isolated from aqueous solutions. Features of 2(4)-AP when interacting with metal ions are discussed. It is proposed that analogs of 2(4)-AP with long hydrocarbon radicals be used for the extraction concentration of platinum metals from hydrometallurgical solutions of complex composition.

The degree of dissolution of nickel(II) hydroxide in mixtures of aqueous solutions of ammonia and ammonium bicarbonate has been studied. The equilibrium between the solid and liquid phases was reached in 11–12 h after the start of experiment. Nickel(II) hydroxide showed higher solubility in the ammonia–carbonate mixture compared with aqueous solutions of ammonia and ammonium bicarbonate. The ratio of ammonium bicarbonate and ammonia concentrations in solution at which the highest degree of dissolution of Ni(OH)2 was achieved was determined. An analytical description of the ion-molecular equilibrium in the ammonia– carbonate mixture was given, and the equilibrium concentrations of molecules and ions in the system were calculated. A stoichiometric equation describing the dissolution of nickel(II) hydroxide in an ammonia–carbonate solution was given.

Values of kinematic viscosity and density are determined for water–acetone–methyl ethyl ketone solutions for the first time in the region of high contents of water and the 20–40°C range of temperatures. Results are used to calculate the molar kinematic viscosity (νm), the Gibbs energy of viscous flow activation (ΔG≠νΔ), and the entropy of viscous flow activation. The viscometric characteristics of this system are compared to those of water–ethanol–acetone, water–2-propanol–acetone, and water–2-butanol–acetone systems studied earlier. Dependences on the concentration of one organic component at a fixed content of a second are presented for different properties. The viscometric parameters of ternary solutions with methyl ethyl ketone, calculated based on size/molecular weight of the components (νm and ΔG≠νΔ), are close to those obtained for solutions with ethanol but notably higher for solutions with 2-propanol and 2-butanol. It is concluded that molecules participating in the formation of intermolecular hydrogen bonds as proton donors (alcohols) raises viscosity more than an increase in size/mass (methyl ethyl ketone). Different ways of calculating the entropy of viscous flow activation (ΔS≠νΔ) are compared on the basis of literature data. It is found that ΔS≠νΔ is higher than that of water in the studied range of concentrations of the ternary water–acetone–methyl ethyl ketone system, which is also typical of other aqueous solutions.

Single phase ceramic samples of new compounds (1 − x)(K0.5Na0.5)NbO3−xLa(Ag0.5Sb0.5)O3 (x = 0–0.15), modified by metal oxide additives ZnO, CuO, and MnO2, are prepared via a solid state reaction. The crystal structure, microstructure, and dielectric and ferroelectric properties of the samples are studied. It is established that a phase with a perovskite structure and an orthorhombic unit cell formed in each sample. Ferroelectric phase transitions are confirmed via dielectric spectroscopy. Generation of the second harmonic is observed, along with a drop in the temperature of transitions from the ferroelectric orthorhombic phase to the ferroelectric tetragonal phase, and then to the cubic paraelectric phase.

A method has been proposed for the synthesis of activated carbon materials (ACMs) based on polyacrylonitrile (PAN) by activation with potassium hydroxide under the action of IR heating. Two approaches to the chemical activation of the polymer precursor were presented: formation of ACM based on PAN preliminarily heat-treated at 200°C and based on PAN carbonized at 700°C by impregnation with an aqueous alkali solution followed by heating to 800°C. Due to the use of IR radiation, the heating can be performed at a rate of 50 K/min, and the exposure time at a given temperature can be reduced to 2 min. The dependence of the specific surface area and porosity of ACM according to BET on the synthesis conditions was studied. The proposed approaches lead to the formation of ACMs with specific surface areas of 1091 and 2121 m2/g, respectively.

Results from calculating the properties of liquid tin using the EAM (Embedded Atom Model) interparticle potential are analyzed, and the surface properties of tin are calculated according to molecular dynamics (MD). Calculations based on the EAM generally agree better with experiments for the properties of liquid tin than ones based on the MEAM. The accuracy of the Gibbs–Helmholtz equation for the relationship between surface tension and surface energy is evaluated.

Electron Auger spectroscopy is used to study the surface segregation of gallium in diluted solid solutions of Al–Ga with volume concentrations of 1.1, 2.4, 4.2, 7.4 wt % Ga at temperatures of room temperature to 573 K. Considerable segregation of gallium is observed for all of the studied alloys. Values obtained for the surface concentration of Ga are used to construct the dependence of the energy of segregation on the surface concentration of Ga atoms at different temperatures

Dynamic mechanical relaxation spectroscopy is used to study the relaxation behavior of elastic alkyl(met) polymers. The items of interest are acrylates on metal substrates before and after UV irradiation of different durations. Analysis is based on comparing the intensity of local dissipative relaxation in irradiated and non-irradiated polymers, along with their glass transition temperatures and elastic properties.

Casting from a solution is used to obtain proton-conducting membranes based on a poly(vinylidenefluoride-co-hexafluoropropylene) copolymer doped with diethylammonium hydrogen sulfate and diethylammonium mesylate with different levels of doping. An IR spectroscopic study is performed, and the phase behavior of the obtained membranes, their thermal and electrochemical stability, and specific electrical conductivity are investigated. It is established that doping protic ionic liquids into PVdF-HFP copolymer reduces the degree of its crystallinity. It has been shown that all membranes are thermally stable up to 290–300°C, and their conductivity at 145°C varies from 1.6 to 10.4 mS cm–1, depending on the level of doping.

The dielectric properties of graphite oxide composite materials based on a biocompatible branched copolymer of N-vinylpyrrolidone with 1,6-hexanediol dimethacrylate and a cross-linked copolymer of N‑vinylpyrrolidone with triethylene glycol dimethacrylate are studied. High-frequency (9.8 GHz) and low-frequency (25 Hz–1 MHz) measurements of the complex permittivity and electrical conductivity of polymer composites are carried out and their dependences on the polymer matrix topology and formation conditions are analyzed. Copolymers and composites based on them are characterized by IR, UV, and visible spectroscopy, dynamic light scattering, and the surface morphology of nanocomposite polymer matrices is characterized by optical microscopy. It is shown that the proposed electrophysical approach makes it possible to additionally characterize polymer matrices with carbon nanofillers.

A network of three-channel low-temperature infrared-optical gas analyzers with a response time of <1 s is developed for detecting explosive and fire hazardous concentrations of gasified liquefied natural gas (LNG) at temperatures up to 150 K. Their characteristics are described in an analysis of its large-scale emissions into the atmosphere. It is shown that during pulsed LNG emissions in the form of submerged jets and spills on standard concrete and water, large-scale areas of mixtures of air, methane, and light alkane vapors form with an explosive concentration that fluctuates in time and volume. The evaporation of cryogenic methane droplets with diameters of more than 0.1 mm in air and methane vapor from temperatures T = 150–290 K has been studied theoretically and experimentally.