V. K. Ivanov

Durable Icephobic Coating for Stainless Steel

In this work, we present a modification of a stainless steel surface to impart superhydrophobic properties to it that are robust with respect to mechanical stresses associated with cyclic icing/deicing treatment, as well as to long-term contact with aqueous media and high humidity. The durability of the superhydrophobic state is ensured by the texture with multimodal roughness stable against mechanical stresses and a 2D polymer network of fluorooxysilane chemically bound to the texture elements. The designed superhydrophobic coating is characterized by contact angles exceeding 155° and a maximum rolling angle of 42° after 100 icing/deicing cycles.

UV-shielding property, photocatalytic activity and photocytotoxicity of ceria colloid solutions.

UV-shielding property, photocatalytic activity and cytotoxicity (including photocytotoxicity) of citrate-stabilized ceria colloid solutions were studied. It was established that UV-shielding property (namely, the sun protection factor, the critical absorption wavelength and the UVA/UVB-ratio) of ceria nanoparticles are as good as those of titanium dioxide and zinc oxide nanoparticles. It was further demonstrated that ceria nanoparticles possesses substantially lower photocatalytic activity, which additionally decreases upon decrease in ceria particle size. It was found that colloid ceria solutions are non-toxic to mouse fibroblasts (L929) and fibroblast-like cells of African Green monkey (VERO). Moreover, ceria nanoparticles are capable to protect these cells from UV-irradiation-induced damage. It was proposed that nanocrystalline ceria could be used not only as UV-blocking material, but also as prophylactic and even therapeutic compound for sunburns treatment.

Oriented attachment of particles: 100 years of investigations of non-classical crystal growth

The results of investigations of non-classical crystal growth by the oriented attachment mechanism are summarized. The data published since the end of the 19th century are considered, the attention being focused on analysis of publications of the last 15 years. Data on characteristic features of the oriented attachment of particles are described systematically. The experimental methods used to elucidate the peculiarities of non-classical crystal growth, including in situ methods, are discussed. The prospects of application of the oriented attachment of particles for the formation of various materials are demonstrated.The bibliography includes 227 references.

Lattice expansion and oxygen non-stoichiometry of nanocrystalline ceria

Generalized dependence of unit cell parameter and oxygen non-stoichiometry on the particle size of nanocrystalline ceria synthesized by a wide variety of solution-based methods was established.

ZnO formation under hydrothermal conditions from zinc hydroxide compounds with various chemical histories

The sequence of phase transformations of zinc hydroxide compounds with various chemical histories during hydrothermal (HT) treatment is studied by X-ray powder diffraction and thermal analysis (TG/DTA). ɛ-Zn(OH)2 (wulfingite) is the major intermediate in ZnO production by the HT process. The micromorphology and photocatalytic activity of ZnO powders are studied.

Cellulose nanofiber–titania nanocomposites as potential drug delivery systems for dermal applications

In this work, new efficient drug delivery systems based on cellulose nanofiber-titania nanocomposites grafted with three different types of model drugs such as diclofenac sodium, penicillamine-D and phosphomycin were successfully synthesized and displayed distinctly different controlled long-term release profiles. Three different methods of medicine introduction were used to show that various interactions between TiO2 and drug molecules could be used to control the kinetics of long-term drug release. All synthesis reactions were carried out in aqueous media. The morphology, chemical structure and properties of the obtained materials were characterized by SEM, TEM and AFM microscopy, nanoparticle tracking analysis, X-ray diffraction, and TGA analysis. According to FT-IR and UV-Vis spectroscopy data, the titania binds to cellulose nanofibers via formation of ester bonds and to drug molecules via formation of surface complexes. The drug release kinetics was studied in vitro for diclofenac sodium and penicillamine-D spectrophotometrically and for phosphomycin using a radio-labeling analysis with 33P-marked ATP as a model phosphate-anchored biomolecule. The results demonstrated that the obtained nanocomposites could potentially be applied in transdermal drug delivery for anesthetics, analgesics and antibiotics.

Planar SERS nanostructures with stochastic silver ring morphology for biosensor chips

Surface-enhanced Raman spectroscopy (SERS) of living cells has rapidly become a powerful trend in biomedical diagnostics. It is a common belief that highly ordered, artificially engineered substrates are the best future decision in this field. This paper, however, describes an alternative successful solution, a new effortless chemical approach to the design of nanostructured silver and heterometallic continuous coatings with a stochastic “coffee ring” morphology. The coatings are formed from an ultrasonic mist of aqueous diamminesilver hydroxide, free of reducing agents and nonvolatile pollutants, under mild conditions, at about 200–270 °C in air. They consist of 30–100 micrometer wide and 100–400 nm high silver rings composed, in turn, of a porous silver matrix with 10–50 nm silver grains decorating the sponge. This hierarchic structure originates from ultrasonic droplet evaporation, contact-line motion, silver(I) oxide decomposition and evolution of a growing ensemble of silver rings. The fabricated substrates are a remarkable example of a new scalable and low cost material suitable for SERS analyses of living cells. They evoke no hemolysis and reduce erythrocyte lateral mobility due to suitable “coffee ring” sizes and a tight contact with the silver nanostructure. A high SERS enhancement, characteristic of pure silver rings, made it possible to record Raman scattering spectra from submembrane hemoglobin in its natural cellular environment inside single living erythrocytes, thus making the substrates promising for various biosensor chips.

Formation mechanism of nanocrystalline ceria in aqueous solutions of cerium(III) nitrate and hexamethylenetetramine

The formation mechanism of ceria nanoparticles in solutions of cerium(III) nitrate and hexamethylenetetramine has been studied for the first time, using UV/visible spectroscopy and x-ray diffraction. The process has been shown to involve, as an intermediate step, the formation of cerium(III) hydroxycarbonate. The effects of synthesis temperature and solution composition on the micromorphology of the powders have been investigated.

Microwave-Assisted Hydrothermal Synthesis and Photocatalytic Activity of ZnO

The effect of synthesis temperature on the morphology of fine zinc oxide powders prepared by microwave-assisted hydrothermal processing of Zn(OH)2 suspensions has been studied using x-ray diffraction and low-temperature nitrogen BET measurements. The photocatalytic activity of the powders for Methyl Orange photodegradation has been assessed as a function of synthesis temperature. The results indicate that the specific surface of ZnO powders plays a key role in determining their photocatalytic activity.

Nanocrystalline ceria based materials—Perspectives for biomedical application

Nanocrystalline ceria possesses a unique complex of physical and chemical properties making it highly bioactive material. In this review, modern data on the action of nanocrystalline ceria on cells, micro- and macroorganisms are analyzed. Special attention is paid to the analysis of the factors affecting protective properties of CeO2 with respect to the living systems.