T. G. Evseeva

Synthesis of Polypyrrole Nanoparticles by Dispersion Polymerization

The influence of pyrrole, oxidant (FeCl3), and polymeric stabilizer (polyvinyl alcohol) concentrations and of temperature on the rate of redox dispersion polymerization of pyrrole, diameter of the forming particles, and their size distribution was studied with the aim to prepare polypyrrole nanoparticles.

Emulsifier-free emulsion copolymerization of styrene with methacrylic acid as a method of preparing building blocks for photonic crystals

Monodisperse polymer particles with diameters from 230 to 420 nm have been synthesized by the emulsifier-free emulsion copolymerization of styrene with methacrylic acid. It has been shown that an initiator, chain regulators, comonomer ratio, and pH of a medium influence the dispersity of latexes, the distribution of carboxyl groups in polymer particles, as well as their swelling behavior and electrophoretic mobility. These characteristics of polymer particles are substantial for designing perfect lattices of three-dimensional photonic crystals on their basis.

Copolymerization of styrene with N-vinylformamide and ethylene glycol dimethacrylate and characteristics of the formed particles

Emulsion and emulsifier-free emulsion polymerization of styrene, N-vinylformamide, and ethylene glycol dimethacrylate are investigated with the goal to form positively charged monodisperse submicron crosslinked particles. The effects of the monomer ratio, the type and concentration of the buffer salt, and the emulsifier concentration on the monomer conversion and on the shapes, size distributions, and surface characteristics of the formed particles are studied. It is shown that, in the surface layers, amino groups prevail over carboxylic groups. The total surface concentration of acidic and basic groups increases with the degree of crosslinking of particles and as a result of their subsequent surface hydrolysis.

Bioligand carriers based on methyl methacrylate copolymers with N-vinylformamide or glycidyl methacrylate

Emulsifier-free emulsion copolymerization of methyl methacrylate with N-vinylformamide and glycidyl methacrylate initiated by a cationic or anionic azoinitiator in the presence of dextran is used to produce monodisperse polymer particles with a developed multifunctional surface. As a result, monodisperse particles are obtained with a diameter of 350–660 nm, the surface layer of which contains, in addition to carboxyl groups, amino or epoxy groups. The conditions are determined for the formation of multifunctional hydrophilic particle surface via the hydrolysis of comonomer units and residual groups of initiators. The limiting values of bovine serum albumin chemisorption (2.4 and 1.0 mg/m2 on the particles of methyl methacrylate copolymers with glycidyl methacrylate or N-vinyl formamide, respectively) indicate that the obtained particles have sufficient sorption capacity to be applied as carriers for immunoreagents.

Crosslinked monodisperse particles containing luminophore groups in shells for molecular recognition of lower alcohols

The molecular imprinting technique is used for the synthesis of monodisperse polymer particles via the seed emulsion copolymerization of methyl methacrylate, ethylene glycol dimethacrylate, and comonomers based on Nile Red. The introduction of lower alcohol templates into the reaction mixture and their removal after the synthesis lead to the formation of molecular-recognition sites in the shell that contain luminophore groups and give an optical response to the presence of methanol and ethanol in the gas phase. The particles are investigated via electron microscopy and dynamic light scattering, and their specific surface area is determined through the BET method. The kinetics of a change in the luminescence of thin films based on the particles in vapors of lower alcohols is investigated.

Synthesis of Polymethyl Methacrylate Microspheres in the Presence of Dextran and Its Derivatives

Emulsion polymerization of methyl methacrylate initiated by a carboxyl-containing azo initiator in the presence of a polymeric stabilizer (dextran or its functionalized derivatives) was studied with the aim to prepare monodisperse microspheres of polymethyl methacrylate with surface carboxy, amido, and aldehyde groups. The optimal conditions for formation of monodisperse microspheres were found, allowing control of their diameter in the submicrometer range and of the nature and content of surface functional groups.

Monodisperse Polystyrene Microspheres Used as Porogenes in the Synthesis of Polymer Monoliths

Formation of a porous structure with the use of monodisperse polymer particles as templates is exemplified by the synthesis of two types of solid macroporous polymer materials featuring different hydrophobic-hydrophilic properties. The materials are prepared via the photo-induced free-radical copolymerization of monomers in the presence of pore-forming agents: strictly spherical polystyrene microspheres with various diameters and natures of the surface. Copolymer samples are analyzed via scanning-electron and atomic-force microscopy, mercury intrusion porosimetry (MIP), porosimetry based on the intraporous adsorption and desorption of gases (BET analysis), IR measurements, and solid-state NMR spectroscopy.

Cross-linked poly(methyl methacrylate) particles with surface amino groups

Positively charged monodisperse particles have been synthesized via emulsifier-free emulsion copolymerization of methyl methacrylate with vinylformamide and ethylene glycol dimethacrylate. The effect of the cross-linking agent on the conversion of the monomers, as well as on the shape, size distribution, and surface characteristics of the obtained particles, has been determined. Addition of the cross-linking agent (5 wt %) to the reaction system has been shown to result in the formation of particles, which, after hydrolysis, have positive ζ potentials at pH 2–10.

Monodisperse polymer particles with molecular imprints of naphthalene in the shell: Synthesis and adsorption properties

Methods of seed heterophase polymerization of ethylene glycol dimethacrylate and its copolymerization with styrene or trimethylolpropane trimethacrylate with the aim to prepare monodisperse cross-linked core-shell particles were studied. The possibilities of molecular imprinting for forming sites for molecular recognition of naphthalene molecules were examined. The adsorption ability of the particles obtained is influenced by the naphthalene concentration and porogenic solvent polarity in the polymerization mixture.

Naphthalene vapor sorption by polymer nanoparticles with molecularly imprinted shells

The process of naphthalene adsorption from the gas phase by layers of core-shell polymer nanoparticles obtained with the use of molecular imprinting methods is studied by the fluorescent analysis method. Within the pseudo-second-order kinetic model of sorption, data on the rate constants of fluorescence change are obtained, primary regularities of the sorption process are determined, and the presence of selective recognition sites in the shells of nanoparticles is proven.