A. A. Averin

Proton-conducting sorption-active cyclam-based layers on chemically modified PVC surfaces of cellulose fabric

At different concentrations of hydrochloric, sulfuric, and phosphoric acids, the conductivity of the following electrochemical cell was measured: anode-acid solution-in-air bridge-acid solution-cathode. Cellulose fabric, the fibers of which are encapsulated in polyvinyl chloride, the surface of which is chemically modified with porous layers of aggregates formed by acid molecules and salt groups of ethanol and acetate cyclams, served as the bridge. The range where the logarithmic conductivity is proportional to the acid concentration is found. In this range, the molar contents of acids and water in the layers are estimated, the presence of aggregates composed of acid hydrates and cyclam salt groups is determined, the structure of layer is studied, and the similarity between the H+ conductivity of the layers on fabric and the conductivity of membranes based on polymers involving the skeleton ammonia salt groups is followed. For the aggregate layers, the specific surface; the limiting volume of pores; and the adsorption capacities for water, alcohol, benzene, and hexane vapors are measured. The formation of aggregates is shown to produce an insubstantial effect on the adsorption characteristics of the surface. During migration of H+ ions in the fabric and on its surface, the following process was carried out in the electrochemical cell: adsorption of NH3, formation of NH4+ ions, and transfer of NH4+ ions to the catholyte. The migration velocity of H+ ions is shown to correspond to the measured current in the circuit, and NH4+ ions formed are found to be accumulated in the catholyte.

Synthesis and proton conductivity of adsorption-saturated and solvated porous hydroxyethylated cyclam layers on the surface of PVC-coated cellulose fabric

Porous layers of associates of adsorption-saturated and benzene- and hexane-solvated chloride and sulfate of hydroxyethylated cyclams with acid aqua complexes were synthesized on the surface of PVC-coated cellulose fabric. The porous structure of the layers includes a system of internal pores connected with the external pores via the diamine rings of the common walls of the hydroxyethylated cyclam nets; the internal pores are filled with the associates; the solvent molecules are adsorbed on the developed surface of the layers or solvate it. The H+ motion rate in a layer placed in solvent vapors or liquid solvents was measured; the layers were found to be nonlinear H+ conductors. The potential of H+ transition from the acid solution into the layer, the H+ mobility constant, and the field variation constant of the H+ mobility of the layer depend on the layer composition. The adsorption and solvation are accompanied by the formation of host-guest molecular complexes between the diamine rings of the cyclam nets and the benzene or hexane molecules, affecting the resistance of the associates to the incorporation of H+ ions and the H+ mobility in the associates.

The formation of urchinlike nanostructures under thermal oxidation and depassivation of iron particles

Methods of scanning electron microscopy with an X-ray probe, Raman spectroscopy, and thermogravimetry are used to study the morphology and composition of metal–oxide nanostructures obtained by thermal oxidation of spherical microparticles of iron powder with a diameter of 1–3 μm. It is shown that unidimensional hematite nanoflakes and fibers grow under atmospheric annealing at 300°C and above in the radial direction from powder microparticles, which is accompanied by depassivation and acceleration of corrosion layer growth. An increase in temperature and oxidation time results in transformation of microparticles into urchinlike multilayer nanoparticles consisting of elongated crystalline α-Fe2O3 nanowhiskers growing normally to the surface of the particle consisting of an iron core and shells of the magnetite and hematite phases. Growth of hematite nanowhiskers continues until the metallic core is completely oxidized.

Heterophase activation of the growth processes of 1D hematite nanostructures under oxidation of plastically deformed iron powders

Methods of scanning electron microscopy with an X-ray probe, Raman spectroscopy, and thermogravimetry are used to study the morphology and composition of metal-oxide nanocomposites obtained by intense plastic deformation of iron powder and the further annealing in the TGA mode. It is shown that high-temperature annealing of activated powder deformation results in the formation of “hematite wood”—a layer of “nanoflakes” and “nanoleaves” growing vertically on the composite surface. In addition to its intrinsic functional (sensor, catalytic, semiconductor, adsorption) properties, this structure possesses pronounced primer properties for further formation of protective surface layers.

Relaxation behavior of latex-polymers in frost-resistant aqueous-dispersion deep-penetration ground coats modified by water-soluble dye

The effect of a water-soluble indanthrene blue dye on the relaxation structure of styrene–acryl latex polymer with the glass-transition point below 5°C is studied in a frost-resistant aqueous-dispersion coat using the method of dynamic mechanical-relaxation spectroscopy. A significant difference is found between the change in the intensity of the maximum of α-relaxation dissipative losses of a latex-polymer binder in the ground coat and in free latex polymer when they are modified by a blue dye, which is due to the ground-coat composition. Special attention is paid to relaxation effects in the negative temperature range.

Effect of corrosion products on the Pu partitioning in rocks of reservoir horizon upon interaction with acidic solutions under hydrothermal conditions

Plutonium sorption on various types of sands of reservoir horizon depends on the presence of corrosion products in solutions simulating highly saline acidic (pH 2.4) liquid radioactive waste (LRW) under hydrothermal conditions (T = 150°C, 50 h). The effect of corrosion products (Fe, Cr) present in LRW consists not only in considerably increased Pu sorption, but also in increased fraction of its strongly fixed fraction. α-Track radiography revealed essentially heterogeneous distribution of Pu between mineral phases of sands of reservoir horizon after interaction with simulated LRW and predominant association of Pu with separate phases containing Fe and Cr (data of X-ray microanalysis based on scanning electron microscopy, SEM-EDX). Examination by Raman spectroscopy and X-ray diffraction analysis showed that the phases responsible for the predominant sorption of Pu are phases of Cr-containing hematite.

Formation of nanocomposites of platinum with nanotubular titanium dioxide

Metal oxide nanocomposites of platinized titania nanotube arrays (Pt-TNT) have been formed via electrochemical anodization-precipitation. Initially, the vertically aligned amorphous TiO2 nanotube arrays (TNTs) were formed in accordance with potentiostatic electrochemical anodization of titanium with the use of 1 M H2SO4 + 0.3% HF electrolyte. Then, using the potentiostatic and pulse electrodeposition, precipitates of Pt on TNT were formed from 0.04 M solution of chloroplatinic acid (CPA). It has been shown with the use of SEM and Raman spectroscopy that, in order to prepare functional metal oxide Pt-TNT nanocomposites, pulse electrodeposition and subsequent annealing at 400°C are preferable, because they lead to TNTs that are homogeneously distributed along the surface and in bulk (with anatase structure) for platinized layers and conglomerates.

Activation of metal oxidation over the zone of electrodiffusion

It is shown that an oxide layer saturated by chromium oxides is formed on the surface of chromium steel at a higher rate under electrocontact (104–105 A/cm2) vacuum dc annealing (10–2 Torr, 300°C) than under furnace heating. Such activation of oxidation is due to the formation of an electrodiffusion zone in the surface steel layer. At further stages, grain boundaries emerge to the metal surface that act as oxidant transportation channels from the surrounding medium into the conductor bulk, which results in accelerated oxide formation in the bulk of the surface metal layer. Apart from the uniform oxide layer, individual hematite nanoflakes and nanoleaves with the thickness of 50–40 nm and average diameter of 450 nm are formed on the positive electrode and grow vertically on the steel surface. The average surface density of nanoparticles is 108 1/cm2. Such activation of metal oxidation over the zone of electrodiffusion can provide pronounced properties for accelerated formation of protective surface layers, in addition to its intrinsic functional (sensor, catalytic, semiconductor, adsorption) properties.

The Photoelectrochemical Activity of Titanium Dioxide Nanosized Films in the Visible Spectral Region

From solutions of organic precursors, nanosized films of titanium dioxide with photoelectrochemical activity in the visible region are obtained. A possibility of photoelectrochemical oxidation of a number of organic compounds under illumination with monochromatic light at a wavelength of 464 nm is demonstrated, which may be due to a decrease in the n-TiO2 band-gap energy to 2.7 eV.

Solubilization of Magnesium Octa[(4′-Benzo-15-Crown-5)Oxy]Phthalocyaninate in Aqueous Micellar Solutions of Hexadecyltriphenylphosphonium Bromide

Electronic absorption spectroscopy and fluorimetry have been employed to study the behavior of magnesium octa[(4′-benzo-15-crown-5)oxy]phthalocyaninate (Mg[(B15C5O)8Pc]) in aqueous micellar solutions of sodium dodecyl sulfate and hexadecyltriphenylphosphonium bromide. Conditions have been found for the existence of monomeric Mg[(B15C5O)8Pc] complex in surfactant solutions to provide the possibility of using mixed solutions of the complex and cationic surfactants (alkyltriphenylphosphonium bromides) for photodynamic therapy. In surfactant solutions with different concentrations of micelles (cm) and the complex (cp), the maximum amount of monomeric Mg[(B15C5O)8Pc] is achieved at cm/cp ≥ 4.