N. A. Matveeva

The influence of the nature of a nanoparticle and polymer matrix on the morphological characteristics of polymeric nanostructures

Comparative studies of the morphological characteristics of selenium- and platinum-containing nanostructures were performed by molecular optics methods. The nanostructures were based on an ionogenic polymeric stabilizer, poly-N,N,N,N-trimethylmethacryloyloxyethylammonium methyl sulfate, and a non-ionogenic polymeric stabilizer, oxyethylcellulose. Studies were performed in aqueous solutions at a fixed ratio between components. The adsorption of a considerable number of polymer macromolecules on nanoparticles with the formation of superhigh-molecular-weight nanostructures with shapes close to spherical was observed for all the nanosystems studied. The thermodynamic state of nanosystems was characterized. Certain morphological characteristics of nanostructures were substantially influenced by the nature of both nanoparticles and polymer matrix.

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.

Stabilizing Selenium Nanoparticles with Chymotrypsin: The Effect of pH and Nanoparticle-Enzyme Concentration Ratios on the Stability of Nanocomplexes

Conditions of the formation of soluble chymotrypsin complexes with selenium nanoparticles are studied. It is established that the aggregative stability of the nanocomplexes is determined by their conditions of preparation, depending also on the medium pH and ratio of selenium: chymotrypsin concentration. It is shown that chymotrypsin has a “protective” effect due to its hydrophobic adsorption on the surface of selenium nanoparticles and hence the hydrophilization of their surfaces due to ionized groups of the protein.

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.

Dehydration of Organic Solvents by Evaporation through Membranes Based on Polyelectrolytic Complexes

Evaporation of binary aqueous-organic mixtures through composite membranes with coatings based on polyelectrolytic complexes including different combinations of polyelectrolytic polycations and polyanions was studied. The possibility of efficient dehydration of organic solvents by their pervaporation was demonstrated.

The Influence of Polymer—Selenium Complex Components and the Molecular Weight of the Ionogenic Polymeric Matrix on the Morphologic Characteristics of Selenium-Containing Nanostructures

Several optical methods were used to study nanostructures formed in the reduction of selenium ions in the selenite—ascorbate redox system in an aqueous solution of the poly-N,N,N,N-trimethylmethacryloyloxyethylammonium methyl sulfate polycation. The relation between the molecular weight of the polymeric matrix, which varied over a wide range, Mw = (0.03−13) × 106, and the morphologic characteristics of nanostructures (molecular weight, density, shape, and statistical and hydrodynamic dimensions) was established. The weight ratio between the components of the polymer: selenium complex and the concentration of the polymer in the reaction mixture were shown to substantially influence certain morphologic characteristics of nanostructures. In the region of the formation of stable dispersions, the Gibbs energy of macromolecule—Se0 nanoparticle interactions was calculated. The thermodynamic state of solutions of nanostructures was characterized.

Influence of the nature of the stabilizing polymeric matrix on the self-organization of selenium nanoclusters

The size characteristics and formation kinetics of selenium-containing nanosystems based on various polymeric matrices (nonionic polymers: polyvinylpyrrolidone, oxyethylated cellulose; cationic polyelectrolyte: poly-N,N,N,N-trimethylmethacryloyloxyethylammonium methyl sulfate; anionic polyelectrolytes: poly-2-acrylamido-2-methylpropanesulfonic acid, polymethacrylic acid) were studied by methods of molecular optics and spectrophotometry. The influence of the nature of the polymeric matrix and of the selenium: polymer weight ratio on the rate constant and hydrodynamic radius was determined.

Formation of a composite based on selenium nanoparticles stabilized with poly-N,N,N,N-trimethylmethacryloyloxyethylammonium methyl sulfate and on Acetobacter xylinum cellulose gel films

Formation of a composite based on selenium nanoparticles stabilized with poly-N,N,N,N-trimethylmethacryloyloxyethylammonium methyl sulfate and on Acetobacter xylinum cellulose gel films was studied. Optimal sorption parameters at which the amorphous form of selenium is preserved in the composite film were suggested.

Synthesis, Structure, and Characteristics of Ultra-High-Molecular-Weight Poly-N-methacryloyloxyethyl-N,N,N-Trimethylammonium Methyl Sulfate

Two procedures for synthesis of water-soluble poly-N-methacryloyloxyethyl-N,N,N-trimethylammonium methyl sulfate are compared. Synthesis occurred by the radical mechanism with the Co(III)-glycine system and with acid catalytic initiation. The effect of the initiator nature and the reaction conditions on the course of polymerization was studied.

Selenium-containing nanocomplexes stabilized by various types of matrices: a study by UV-visible spectroscopy

Selenium-containing nanosystems based on nonionic polymers (polyvinylpyrrolidone, oxyethyl cellulose), a cationic polyelectrolyte (poly-N,N,N,N-trimethylmethacryloyloxyethylammonium methyl sulfate), and anionic polyelectrolytes (poly-2-acrylamido-2-methylpropanesulfonic and polymethacrylic acids) were studied.