Volume 11, Nº 11-12 (2016)

The scientific and technological bases of creation of commercial superhydrophobic materials and coatings on the basis of nanotechnologies, the characteristics and specifications of marketable superhydrophobic products in connection with the areas of practical applications, and the current state and prospects of development of their markets in the forthcoming years have been reviewed.

Modern science and clinics today widely apply methods and constructs that are based on superparamagnetic particles. This includes both disease diagnostics and the isolation of certain cell populations, organelles, proteins, and nucleic acids for further investigation. Although separation using superparamagnetic particles is not the only technique for isolating different biological agents, it is one of the most sensitive methods. Constructs with superparamagnetic nanoparticles are successfully applied in oncology, in particular, for hyperthermia treatment. Thus, the nanoparticles are promising for known applications and could serve as a basis for finding new effective methods for treatment of oncology.

The changes in atomic and electronic structure of the Au₁₃ gold cluster caused by the interaction with C₅₄ graphene nanoflake have been studied using computer simulation in the electron density functional approximation. The mechanism of cluster charge effect on the energy of atomic hydrogen adsorption is determined.

Nanostructured silver–amino anion exchanger composites have been synthesized as catalysts for the low-temperature oxidation of methanal with molecular oxygen in aqueous solution. The oxidative conversion of methanal reaches 80–100% at 298 K. The methanal oxidation reaction is size-dependent, and its rate increases with a decrease in the silver nanoparticle size. The fixed amino groups of anion-exchange matrix play the role of additional active sites for the adsorption of methanal in the form of methylene glycolate–anions, which facilitates the reaction.

A number of MK-40 cation-exchange membrane samples modified with ceria have been obtained. The membranes have been studied using a set of physicochemical methods, including impedance spectroscopy, scanning electron microscopy, microanalysis, transmission electron microscopy, and XRD phase analysis. It has been shown that the introduction of cerium oxide reduces the humidity content and ionic conductivity of membranes. It is accompanied by a marked increase in the membrane selectivity expressed by a decrease in transfer numbers with respect to anions.

The effect of solvent and thermal annealing on the structure of active layers in polymer–polymer solar cells has been studied. It has been established by atomic force microscopy (AFM) and X-ray grazing-incidence diffraction that the annealing of films improves phase separation and produces domains that are more compact. Real-time studies have also been carried out on the formation of films of nonpolar (toluene) and polar (chlorbenzene) solvents with simultaneous measurement of the structure and conductivity of the films. It has been established that in both cases the formation of the structures of donor and acceptor domains is a two-stage process, with the stages, however, being noticeably different and determined by physical and chemical properties of the solvents.

This paper provides an overview of the main types of carbon nanostructures: fullerenes, nanotubes, and nanohorns. The newest carbon nanomaterials, nanographitized activated porous carbon containing nanohorns, is studied. The results of experimental data are used to study the properties of the nanographitized carbon: electric properties, sorption, and its impact on water.

With the help of a complex of methods of disperse-structure analysis of nanopowders of plasmachemical synthesis, the function of particle-size distribution and its main characteristics—the average size and dispersion—are studied. A generalization of results of disperse characteristics for nanoparticles formed with the participation of various mechanisms—“vapor–solid” and “vapor–liquid–solid”—is carried out. It is shown that the formation of titanium nitride and carbonitride nanoparticles proceed on the vapor–solid mechanism without the participation of coagulative-particle growth. For the nanopowders under study, it is established that the variation range of standard deviation for the distribution function is in the interval of 30–60% of the average diameter; the index of aggregation is defined in the range of 1.5–3.0. It is revealed that the logarithmically normal function of particle-size distribution most authentically (with a correlation coefficient of more than 0.95) describes all studied objects for all mechanisms of particle formation in a wide range of dispersion of the received nanopowders independently of process parameters and organization of gas-disperse stream in the plasma reactor. Hypothetically, the established lognormal particle-size distribution is determined by the lognormal distribution of nanoparticles by residence time in the growth zone.

The electronic and vibrational characteristics of a Y splitter based on trans-polyacetylene molecular chains are studied using the density functional method. It is shown that the localized electronic states are formed at the branching point. Their energy is determined by the mutual orientation and length of the branches. The Raman-active localized vibrational modes are present in a phonon spectrum of a splitter. The intensity of the fundamental oscillation is determined by the maximum length of the linear conjugated fragment of a splitter.

The results of our study of the size, optical properties, and aggregate stability of silver nanoparticles in aqueous solutions 1, 2, and 12 months after their synthesis are reported. It has been shown that nanoparticles synthesized using a combined application of physical factors, such as ultraviolet radiation, ultrasound, and uniform mixing (providing conditions of isolation from the atmospheric air) are smaller in size (from 1 to 10 nm) and have more homogenous distribution of the diameter of nanoparticles. A lower aggregation has been noted compared with particles prepared without observing the synthesis algorithm that was developed and conditions given above. The results of studying antimicrobial antiseptic properties based on a colloidal nanosilver solution prepared using the technology of diffusion-cavitation photochemical reduction of silver nitrate are also reported. A high antimicrobial activity of the resulting colloidal solution with silver nanoparticles against clinical isolates of P. aeruginosa, A. baumanii, and E. coli has been demonstrated as compared with the original silver nitrate and the ligand (polyvinylpyrrolidone) used in the synthesis of the colloid at the same concentration. At a concentration of 10 μg/mL, a colloidal solution with silver nanoparticles has been found to possess bactericidal activity against two isolates of P. aeruginosa, three isolates of A. baumanii, and five isolates of E. coli. At a concentration of 1 μg/mL, the colloidal solution of silver nanoparticles has possessed only bacteriostatic activity against all isolates of the bacteria. The minimum bacteriostatic inhibitory concentration of nanosilver has determined to be 3 μg/mL.