A. Ya. Volkov

Formation of a composite from Se0 nanoparticles stabilized with polyvinylpyrrolidone and Acetobacter xylinum cellulose gel films

Formation of a composite from Se0 nanoparticles stabilized with polyvinylpyrrolidone and Acetobacter xylinum cellulose gel films was studied. The optimal sorption parameters at which the amorphous form of the selenium complex is preserved in the composite were suggested.

Morphology and electronic structure of platinum-containing polymer nanosystems

Morphological characteristics and electronic structures of platinum-containing nanosystems obtained during a redox reaction in water medium at different concentrations of a stabilizing polymer and platinum were studied by atomic-force microscopy (AFM), X-ray photoelectron spectroscopy, and dynamic light scattering. It was shown that individual and associated structures of different morphologies were formed on the silicon substrate surface. Comparison of the dimension characteristics of nanoclusters in the Pt nanoparticle-polymer systems (in solution by means of molecular optics, on the silicon substrate surface in air by means of AFM) for ionogenic and nonionogenic polymer matrices upon the change of the mass ratio ν has shown that the nanocluster sizes in solution are two to three times larger than those in a thin film formed on the substrate surface. The size dependences of the nanoclusters on ν obtained by these methods exhibit the same character.

Model of packing of cellulose acetomyristinate in Langmuir-Blodgett films

The variation of the structural characteristics in the transition from a block polymer to a Langmuir-Blodgett film has been investigated for cellulose acetomyristinate by the methods of X-ray diffraction analysis. The effect of length and number of acid residues on the diffraction pattern of block cellulose acetomyristinate is studied. The role of acyl substituent in the formation of an ordered structure of multilayer Langmuir-Blodgett films is established. A model of packing of cellulose acetomyristinate molecules in the Y-type films is suggested. The model is based on a two-domain structure in which close-packed myristic-acid residues are located either normally or at a certain angle to the plane of glucoside rings on one side of the polymer chain.

Biogenic selenium-containing nanosystems based on polyelectrolyte complexes

The kinetic, structural, and morphological studies showed that the composition of polyelectrolyte complexes (PECs) and the selenium/PEC mass ratio affected the formation of biogenic selenium-containing nanosystems and their structural and morphological properties.

Effect of montmorillonite on the structure and properties of powder epoxy compounds for polymeric coatings

Procedures for preparing nanomodified powder epoxy compounds with various concentrations of montmorillonite were examined. The dispersion of particles in the epoxy oligomers was studied by X-ray diffraction analysis and electron microscopy. The influence of the content of the modifiers on the physicomechanical properties of cured block specimens was analyzed.

Structural Parameters of Cellulose Produced by Acetobacter Xylinum and Their Variation in the Course of Drying of Gel Films

The cellulose-producing power of the VKM V-800 Acetobacter xylinum strain under conditions of static culture was studied. The culture medium was optimized with the aim to increase the cellulose yield and obtain highly crystalline cellulose I with molecular weight of about 5 × 105.

Hybrid polymer nanosystems based on selenium and zinc-selenide nanoparticles: Morphology, electronic structure, and thermodynamic properties

The structure and morphology of hybrid nanosystems based on selenium and zinc-selenide nano-particles stabilized by water-soluble polymers—polyvinylpyrrolidone and polymethacrylic acid, are studied by methods of atomic force microscopy (AFM), high-resolution electron microscopy, transmission and scanning electron microscopy (TEM and SEM), X-ray photoelectron spectroscopy, X-ray structural analysis, and static light scattering. Comparison of the size characteristics of the nanostructures in the nanoparticle/polymer systems upon an increase in the weight ratio (ν) of the system components, using static light scattering in a solution and AFM, SEM, and TEM on the substrate surface, shows that the sizes of the forming nano-structures change nonmonotonically. The thermodynamic characteristics of the nanostructures in the solution are determined. It is shown that depending on ν, nanostructures of various morphologies may be formed, including spheres and irregularly shaped micelles with cores of different sizes.

AFM analysis of the surface morphology, structure, and mechanical properties of methylcellulose mixtures with colloidal silver dispersions

The surface morphology, structure, mechanical properties, and physical transition temperatures of film compositions between methylcellulose (MC) and colloidal silver dispersions (CSDs) stabilized by poly-N-vinylpyrrolidone (PVP) are studied via atomic-force microscopy (AFM), X-ray diffraction and thermomechanical analyses, and mechanical tests. It is established that composite films exhibit the characteristic granular (nanodomain) surface morphology. When the CSD content in the compositions increases, the degree of ordering of MC macromolecules enhances, grain sizes decrease from ∼75 to ∼60 nm (at 3 and 20 wt % of the CSD, respectively), and the film surface relief becomes smoother. For example, the surface roughness of composite films is three times less than that of the initial MC film. In other words, owing to CSD introduction, film compositions are structurized at the nanolevel. In this case, Young’s modulus and the yield stress of composite films increase successively. High-temperature heating increases the average nanodomain size to 120–180 nm (for mixtures with 20 wt % of the CSD) and stimulates the local ordering of MC macromolecular fragments with sizes of ∼3–5 nm.

Structure, Morphology, and Thermal Properties of Polyrotaxanes Based on Calix(6)arene and Modifi ed Polydimethylsiloxane

New supramolecular inclusion complexes, polyrotaxanes derived from p-tert-butylcalix[6]arene and polydimethylsiloxane modified with terminal epoxy groups, were synthesized and studied. The dependence of the structure, morphology, and thermal properties of polyrotaxanes on the molecular weight of the linear polymer was determined.

Structure and thermal properties of polyrotaxanes derived from γ-cyclodextrin and modified polydimethylsiloxane

Supramolecular inclusion complexes, polyrotaxanes, derived from γ-cyclodextrin and polydimethylsiloxane modified with terminal epoxy groups were studied. The dependence of the structure, morphology, and thermal properties of polyrotaxanes on the molecular weight of the linear polymer, molar ratio of γ-cyclodextrin and polymer, and presence of free γ-cyclodextrin in the complexes was examined.