Influence Of Low-temperature Plasma Research Articles

The Influence of Low-Temperature Plasma on the Structure of Surface Layers and Gas-Separating Properties of Polyvinyltrimethylsilane Membranes

New results of one-sided surface modification of polymeric films and composite membranes of polyvinyltrimethylsilane (PVTMS) using low-temperature plasma are presented. The treatment was carried out by direct current discharge at the cathode and anode, air was used as the working gas, the exposure time was from 10 to 60 s, and the working pressure in the chamber was 15–20 Pa. The structure of the surface layers was analyzed by XPS, AFM and SEM, and the contact properties of the surface were also studied. The effective permeability coefficients for O2, N2, CH4, CO2, He, and H2, as well as for gas diffusion, for cathode-treated PVTMS films are experimentally obtained, and the effective gas solubility coefficients are calculated. The permeability coefficients of the studied gases for composite membranes with a selective PVTMS layer modified at the cathode and anode were determined. It has been noted that the choice of electrode significantly affects not only the chemical structure of the surface and near-surface layers of PVTMS, but also the gas transport parameters of the modified samples. At the same time, during the treatment of PVTMS films at the cathode for 30 s, it was possible to achieve an increase in the O2/N2 selectivity by more than two times relative to the initial value. It has been established that the results of modification of composite membranes differ from those obtained for homogeneous films and it was possible to achieve O2/N2 selectivity in 2.5 times higher than the initial value. The potential of using surface modification of polymer films and membranes by low-temperature plasma to improve their gas separation properties is shown.

The influence of low-temperature plasma on the electromagnetic spectrum structure of the selected liquid

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Influence of low-temperature plasma on green algae culture

Influence of low-temperature plasma, which was formed in a high-resource arc-discharge plasma jet in an argon-air mixture, was studied for a community of green algae as Chlorella vulgaris Beyerinck [Beijerinck] and Stichococcus bacillaris Nägeli. It was found that the plasma treatment for 10 minutes led to partial cell death. At the same time, the species of C. vulgaris were less sensitive to the plasma treatment than the species of S. bacillaris. After plasma exposure, the predominant growth of the latter culture was observed in comparison with the control samples. This effect can be explained by an activation of biochemical processes in the algae due to the interaction with radicals in the low-temperature plasma. The results obtained indicate the selectivity of the low-temperature plasma effect on green algae community.

Influence of the low-temperature plasma of the atospheric barrier discharge on the structure and properties of the membranes erythrocytes and platelets

The plasma of the atmospheric barrier discharge (PBR) is used to treat various types of diseases and damage to the skin and soft tissues; however, the mechanism of interaction of PBR with biological material has not been precisely established to date. One of the promising methods for estimation changes in the structure and properties of cell membranes at the nanoscale is atomic force microscopy (AFM). In this article the results of the influence of the barrier discharge low-temperature plasma on the structure and properties of erythrocytes and platelets are presented. By the AFM-method, the shape, morphology of membranes, and adhesive forces on the surface of the cells were determined, which is one of the characteristic parameters for assessing changes occurring at the molecular level with the cell membrane. In this work, we used an experimental complex for generating a low-temperature plasma of a dielectric barrier discharge based on a coaxial type device and an adjustable source power from 10 to 30 W. A change in the structure of the erythrocyte membranes without changing the shape of the cells themselves was established. On the non-fixed erythrocytes, the adhesion force is increased after exposure. On the surface of both erythrocytes and platelets, the presence of particles of submicron size was established, which may be due to the release of cell contents or the destructive effect of plasma on the proteins of the outer layer of the membrane. The cells, which are fixed with a 0.5-mm solution of glutaraldehyde on mica substrates, both retain their disk-like shape and membrane structure, which may be due to the formation of covalent cross-links between membrane lipids and glutaraldehyde, and residual liquid content in the cell volume after interaction with a chemical reagent. Red blood cells are more resistant to short-term exposure to PBR (1 minute) compared with platelets. The results of the studies can be used to establish patterns and the biochemical processes under the influence of PBR on blood cells.

Исследование влияния низкотемпературной плазмы и паровой стерилизации на свойства трековых мембран из полиэтилентерефталата

Исследование влияния низкотемпературной плазмы и паровой стерилизации на свойства трековых мембран из полиэтилентерефталата

The Features of Nanocomposite Structure Formation on the Surface of Metal Products under the Influence of Low-Temperature Plasma

The work presents the study of technological considerations of the nanocomposite structure formation on complex profile surfaces under the influence of low-temperature plasma aimed at wear resistance increase of metal products, the research being conducted on the novel plant.

Interaction of low-temperature plasma with knitted fabric based on natural cellulose fibers

The influence of low-temperature plasma on a knitted fabric of natural cellulose fibers is considered. It is shown that the plasma ion energy is sufficient for the waxy layer destruction. It was determined that the ion bombardment and the paraffin vaporization lead to disintegration of the natural waxy fiber layer and cause the defects in paraffin layer. The local ruptures of carbon chains of alkane molecules of the paraffin layer are caused by the lowenergy plasma ions bombardment and the ions recombination. The alkyl radicals which react with the plasma gas particles and with each other were identified. As a result of reactions of radicals, the hydrophilic functional groups was evaluated by IR spectroscopy and secondary ion mass spectrometry. All these changes facilitate the penetration of the working solutions in the fiber. Plasma effect leads to an increase in the hydrophilic properties of the material and can replace the liquid processes of preparing knitted fabrics for dyeing.

Modification of ultra-high-molecular-weight polyethylene fibers and powders using low-temperature plasma

Literature data on the surface modification of ultra-high-molecular-weight polyethylene as fibers and powder under the influence of low-temperature plasma are analyzed. The change in polymer chemical composition and structure is described. The results of the studies, indicating a significant improvement in the contact and adhesion characteristics of the modified polymer and composite materials, are discussed.

Influence of low-temperature plasma and γ radiation on the surface properties of PET track membranes

Physical and chemical properties of the surfaces of polyethylene-terephthalate (PET) track membranes (TMs) exposed to low-temperature atmospheric plasma and to γ radiation produced by 60Co isotopes are studied. It is established that the exposure to plasma leads to changes in the chemical composition of the surface and increases the number of polar (carbonyl and carboxyl) functional groups in a thin near-surface layer of a TM. The surface energy is also shown to grow owing to its polar component and surface reconstruction. The reconstruction consists in the growth of surface roughness owing to oxidation-reduction reactions, followed by the appearance of destructive areas. These changes promote a lyophilic behavior of the track-membrane surface. Subsequent γ irradiation of the surface is shown to reduce the plasma-modified TM undulation, while decreasing the number of destructive areas and bringing the material into a more equilibrium state.

Plasmochemical modification of polymer surfaces

Influence of low-temperature plasma on the polymer surface was studied with the aim of preparing polymers with required surface properties.