Том 85, № 4 (2023)

Powders of magnetite and its composites have been obtained on the basis of macroporous highsilica glass particles containing different amounts of Fe3O4. XRD, XPS, and Raman spectroscopy have been employed to confirm the formation of a magnetite phase in all iron-containing samples. The surface morphology and elemental composition of porous composite particles have been studied by SEM and EDX methods. It has been found that the external surface of porous silica particles is modified to different extents. It has been shown that the positions of the isoelectric point (IEP) and the values of the zeta-potentials for the composites coincide in indifferent electrolyte solutions. Two isoelectric points are observed in the pH dependences of the zeta-potential for the composite particles in nickel chloride solutions. In dilute solutions containing specifically adsorbed nickel ions and at pH values pHIEP-2, the electrokinetic properties of the composite particles are primarily affected by magnetite phase content in a composite powder and, at rather high concentrations of Ni2+ ions, by their specificity with respect to oxide surfaces.

The chemical compositions, structures, and electrokinetic potentials have been studied for silvercontaining Janus-type ZnO/Ag nanoparticles, heterophase Cu/Ag nanoparticles with a uniform distribution of the components over a particle, and silver-decorated TiO2 nanoparticles. The nanoparticles have been obtained by the simultaneous electric explosion of two wires. The influence of nanoparticle surface structure on the isoelectric point position and electrokinetic potential values has been analyzed. The effect of silver localization on the electrokinetic characteristics of nanoparticles has been investigated. These characteristics have been compared with those of mechanical mixtures having the same mass ratios of the components.

Nickel nanoparticles are obtained by electrical explosion of wire under the action of a high-voltage discharge followed by condensation in an inert gas medium. When butane is added to the gas medium, a carbon shell is deposited onto the condensing nickel particles. Immediately after the synthesis, liquid-phase modification of nanoparticles is carried out with aqueous solutions of polysaccharides agarose and gellan. As a result, a polymer shell is formed on particles of Ni and nickel particles coated with a carbon shell (Ni@C). The dispersity, crystalline structure, and magnetic properties of Ni and Ni@C nanoparticles are characterized by transmission microscopy, X-ray diffraction analysis, and vibration magnetometry. The total carbon
content on the surface of the nanoparticles is determined by thermal analysis with simultaneous mass spectrometry. It is shown that, under the studied conditions, polysaccharides are deposited onto the nanoparticles in amounts up to 2 wt % to form a shell with a thickness of about 4 nm. When agarose is used as a modifier, the content of the polysaccharide increases with the concentration of the modifying solution. When gellan is used as a modifier, a more complex concentration dependence is observed: an initial increase is followed by a decrease in the amount of deposited polysaccharide. The results are discussed from the viewpoint of the influence of the molecular weight of a polymer on the adsorption process.

Theoretical asymptotic calculations linear with respect to small dimensionless amplitude of oscillations have been employed to study the influence of the viscoelastic properties of a charged droplet of an electrically conducting viscous liquid on the intensity of its electromagnetic radiation. It has been shown that allowance for the effect of viscosity relaxation leads to a decrease in the damping decrement value, which is determined by energy losses for electromagnetic wave emission, and the intensity of high-frequency electromagnetic radiation; a substantial reduction in the viscous damping decrement of small cloud droplets; and an essential dependence of the viscous damping decrement on the characteristic relaxation time. It has been found that the viscosity relaxation of a liquid has no significant effect on damped capillary oscillations and electromagnetic radiation of rain droplets. Viscoelasticity and viscosity of the liquid do not influence the conditions critical for the realization of the electrostatic instability of a droplet with respect to its own charge.

The regularities have been studied for the formation of molecular associates upon the introduction of papain into a sodium alginate colloidal solution in the laminar low-speed, transient, and turbulent stirring regimes. The relationship between variations in the sorption capacity of the biopolymer composition and the kinetic regularities of the interphase transfer has been studied during the sorption binding of albumin, which is one of the protein-based components of wound exudates, with such components being subject to ensimatic cleavage. The state of the dispersed phase of the colloidal solutions has been estimated by the dynamic light scattering method. The properties of the formed biopolymer films have been studied using the methods of scanning electron microscopy, low-temperature nitrogen adsorption, and static albumin sorption from solutions of limited volumes. The data of the sorption experiments have been analyzed using the Boyd, Morris–Weber, and gel diffusion models, as well as the Lagergren pseudo-first-order and Ho–McKay pseudo-second-order kinetic models. The data have been obtained for substantiating the dosages of the biopolymermatrix used on wound-healing bandages and for the efficient binding of wound necrotic contamination during the time preset according to the technical requirements.