Nanotechnologies in Russia最新文献

The results of the synthesis and spectroscopic study of the photocatalytic activity of water-soluble arabinogalactan-stabilized zinc oxide nanoparticles are presented. Thanks to the stabilizing ability of the natural polysaccharide arabinogalactan, a composite containing 1.2% ZnO nanoparticles measuring 1–4 nm is obtained for the first time. The photocatalytic activity of the obtained composite in the process of ultraviolet-induced decomposition of the systemic herbicide clopyralid is studied using spectroscopic methods. It is found that this activity directly depends on both the type of radiation (visible/UV) and the concentration of aqueous solutions of the composite.

Microcapsules formed by the layer-by-layer assembly method represent a promising object of nanotechnology that has been actively developed over the past 25 years. The intermolecular interactions used in the creation of such capsules are considered: electrostatic, hydrophobic, hydrogen, covalent, host–guest, and biospecific. Bonds responsible for the assembly of classical multilayer polyelectrolyte capsules are described, as well as alternative, less common, cases of layered shell formation. The formation of nanocomposite shells of multilayer capsules with inorganic nanoparticles is considered from the point of view of intermolecular interactions.

Materials based on uniaxially oriented poly(L-lactide) (PLA) nanofibers are obtained using the electrospinning method. A study of the structure, carried out using scanning electron microscopy, X-ray diffraction, and differential scanning calorimetry, shows that the nanofibers are characterized by an amorphous structure with the orientation of macromolecules relative to the axis of the nanofiber, i.e., a liquid-crystalline-type structure. The strength of such nanofibers is 78.3 MPa, the modulus of elasticity is 11.25 MPa, and the elongation at break is 142%. Heat treatment in the isometric state at T = 80°C and above leads to the formation of α-form crystalline regions oriented relative to the nanofiber axis. Treatment at T = 160°C leads to the partial recrystallization of PLA, the formation of a second phase, and β-form crystals. The presence of a mixture of α- and β-modification crystals leads to a decrease in the strength and elastic characteristics of the nanofibers.

Lead-containing heterovalent solid solutions R_1–yPb_yF_3–y (R is rare-earth elements) with a tysonite-type structure (space group (Pbar 3c1)) are promising solid electrolytes for fluorine-ion current sources. Powder samples of concentrated nanoscale solid solutions R_0.85Pb_0.15F_2.85 (R = La, Pr) are obtained by mechanochemical synthesis from individual components PbF₂ and LaF₃ (PrF₃). The lattice parameters are equal to a = 7.1897(7) Å, c = 7.3545(8) Å and a = 7.0843(6) Å, c = 7.2444(7) Å for compositions with R = La and Pr, respectively. The ionic conductivity of cold-pressed R_0.85Pb_0.15F_2.85 nanoceramics in the temperature range of 297–816 K is studied using impedance spectroscopy. The ionic conductivity values are 2.0 × 10^–3 and 4.3 × 10^–3 S/cm (500 K) for La_0.85Pb_0.15F_2.85 and Pr_0.85Pb_0.15F_2.85 nanoceramics, respectively. The mechanism of ionic conduction is due to the migration of fluorine vacancies along the boundaries of crystalline grains. The conductivity characteristics of R_0.85Pb_0.15F_2.85 ceramics (R = La, Pr) allow us to consider them as promising fluorine-conducting solid electrolytes for low-temperature research and practical applications.

Copolymer films of acrylic acid butyl ether and styrene modified with graphene oxide (GO) (0.1–2.0 wt %) with different average lateral sizes of nanosheets (25 and 250 µm) are obtained by simply mixing aqueous dispersions. The films are characterized using Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). Water absorption is also measured for the films and mechanical tests (tensile strength) are performed. It is shown that small additives of GO act as a coalescent and increase the thermal stability and Young’s modulus of films. It is established that films modified with GO with a larger nanosheet area have higher mechanical characteristics.

Magnetron sputtering is a promising plasma technology for the synthesis of functional nanostructures for various purposes. Analysis of the results of research conducted at the National Research Center “Kurchatov Institute” and by other research teams demonstrates the possibility of effectively using magnetron sputtering to solve problems in electrochemical and hydrogen energy. The current areas of application are the synthesis of functional nanostructures such as nanofilms, nanolayers, nanoparticles, and nanocomposites to increase the efficiency and service life of electrochemical devices (hydrogen fuel cells, electrolyzers, lithium-ion and lithium–sulfur batteries); the development of nanostructured hydrogen storage systems based on magnesium hydride, carbon nanomaterials, and certain other compounds; the creation of composite membranes with a nanostructured surface selective/catalytic layer for the purification and release of hydrogen. The results considered indicate the need to expand the application of this technology for creating functional nanostructures in Russia.

An overview of the current status and prospects of development of intermediate-temperature water (steam) electrolyzers with a polymer membrane is presented. The advantages of carrying out the electrolysis process at temperatures of up to 200°C are shown, and the membrane, electrocatalytic, and construction materials used are considered. The prospects for further development of the technology of intermediate-temperature electrolysis with a proton-conducting polymer membrane are analyzed.

The possibility of creating a biocompatible FeRh sample modified by plasma polymerization was investigated, using cyclopropylamine to create a biochemically active and antibacterial surface coating. FeRh alloy samples were synthesized, annealed and coated using radio-frequency plasma setup, followed by characterization using scanning electron microscopy, Fourier-transform infrared spectroscopy and water contact angle measurements. The results confirmed the successful deposition of cyclopropylamine polymer layers significantly enhancing surface wettability and cell adhesion. Mouse embryonic fibroblasts adhered well to modified FeRh samples, indicating biocompatibility and potential for biomedical applications. These results highlight the possibility of using plasma-modified FeRh samples as candidates for magnetic field controlled drug delivery systems.

Pseudomonas aeruginosa is one of the leading bacterial pathogens causing chronic respiratory infections and is associated with high mortality in cystic fibrosis. Given the increasing antibiotic resistance of P. aeruginosa, the development of alternative treatment methods, including the creation of phage cocktails that provide more effective antibacterial therapy through lytic activity and the inhibition of biofilm formation, is an urgent task. A phage cocktail SF1 is created from 10 lytic phages active against P. aeruginosa PAO 1. The lytic activity of the phages and SF1 is evaluated against 27 clinical isolates of P. aeruginosa from cystic fibrosis patients and seven strains from a veterinary laboratory. Genomic analysis shows the absence of virulence and lysogeny genes in phages, which confirms the safety of the developed cocktail. In vitro, SF1 facilitates the complete lysis of 17 out of 34 tested strains.

Issues related to the determination of equivalent (averaged) values of the specific conductivity of films made of nanometer-thick materials under the influence of electromagnetic fields are considered. The significant roughness of the substrates with films does not allow us to compare their conductivity values with their thickness, so the main task is to obtain analytical expressions for the equivalent conductivity from the film thickness for various materials that can be used in modeling complex structures. To approximate the equivalent conductivity from the film thickness, a model of the diffraction of electromagnetic fields on a conductive nanoplane and known results of experimental studies for the coefficients of power reflection, transmission, and absorption (optical coefficients) are used.