S. A. Smirnov

Simulation of the Processes of Formation and Dissociation of Neutral Particles in Air Plasma: Kinetics of Neutral Components

The results are given of calculations of the concentration of basic neutral particles and of the energy balance in an air plasma in the positive column of a d.c. discharge at pressures of 30 to 300 Pa and currents of 20 to 110 mA. The calculations are based on a combined solution of the Boltzmann equation; equations of vibrational kinetics for the ground states of molecules of N2, O2, and NO; and of the equations of chemical kinetics for these molecules, their excited states, and dissociation products. The results are compared with the measured concentrations of O(3P) atoms and NO molecules and with the effective vibrational temperatures of N2(X1Σ+g). The measured values of gas temperatures and temperatures of the reactor wall are used to find the fractions of energy transforming to heat in the plasma volume, which are compared with the calculation results.

The characteristics of electrons and vibrational distributions of molecules in an atmospheric-pressure liquid-cathode dc discharge in air

Results are given of the calculation of vibrational distribution of N2, O2, and H2O molecules and of electron energy distribution functions in the plasma of atmospheric-pressure dc discharge with a distilled-water cathode. The system of equations of vibrational kinetics is solved simultaneously with the Boltzmann equation using the measured values of reduced electric-field strength, of discharge current density, of gas temperature, and of band intensities of the second positive system of N2 molecules.

The Simulation of the Processes of Formation and Decay of Neutral Particles in DC Discharge Plasma in an Argon-Oxygen Mixture

Results are given of calculations of concentrations of fundamental neutral particles in the positive column of a dc discharge in an argon-oxygen mixture. The calculations are based on simultaneous solution of Boltzmann equation, vibrational kinetic equations for the ground state of O2 molecule, and chemical kinetic equations for the ground and excited states of O2 molecules and Ar and O atoms with the experimentally determined value of reduced intensity of electric field E/N. The results are compared with measured values of radiation intensities of lines of 811.5 nm (Ar) and 845 nm (OI) and of atmospheric band O2(b1Σg+ → X3Σg−, 0-0).

The Treatment of Textile Materials in Air Plasma

The effect of treatment in an air glow-discharge plasma on a poly(ethylene terephthalate) film and fabric with different specific surface areas was examined. The rates of mass loss, oxygen uptake, and evolution of gaseous products (CO2 СО, H2O, H2) were measured over the pressure range 50–200 Pa at a sample temperature of 357 K. It was found that textiles with different textures had different specific etching rates. Possible reasons for this phenomenon are discussed.

Surface Oxidation and Degradation of Polyethylene in a Mixed Argon-Oxygen Plasma

Changes in surface chemical composition and the rates of formation of gaseous degradation products under the action of a mixed argon-oxygen plasma on polyethylene (PE) were studied using multiple attentuated total internal reflection (MATIR) IR spectroscopy and mass spectrometry. It was found that the dilution of a gas mixture with argon decreased the rate of degradation of the material at argon contents higher than 30%. It was demonstrated that absorbance at the absorption bands of the main oxygen-containing groups in a PE film remained unchanged over an argon concentration range from 0 to 90%. Conceivable mechanisms of processes occurring in gas and solid phases, which allowed us to describe the phenomena observed, are discussed.

Physicochemical processes in the nonequilibrium plasma-polymer system

The results of investigation into interaction between nonequilibrium plasma and polymers, including the mechanism of generation of active species in a direct-current discharge in oxygen, air, and oxygen mixtures with argon, are reported, and the formation behavior of gaseous products of the reactions of these species with polymer is discussed. The influence of the gaseous products on the physical characteristics of plasma and the rates of the processes involving electrons is considered.

Kinetic Features of Initiation of Poly(ethylene terephthalate) Oxidative Degradation Processes in Oxygen Plasma

The results of measurements of time dependences for the formation rates of gaseous products and oxygen uptake rate in oxygen plasma treatment of a poly(ethylene terephthalate) film at discharge currents of 20–80 mA and a pressure ranging within 50–200 Pa are reported. The obtained data allow the authors to speculate on the mechanism of initiation of plasma-induced oxidative degradation of the material.