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Scientific aspects of technologies based on application of non-equilibrium oxygen plasma are presented. Oxygen plasma is sustained by an electrodeless discharge to facilitate a high concentration of neutral reactive species, in particular O atoms. The species interact with solid materials causing surface functionalization, removal or organic impurities, nanostructuring of polymers, selective etching of polymer composites or synthesis of metal-oxide nanoparticles. The flux of O atoms onto the surface-facing plasma is often between 1020 and 1023 m-2 s-1. While the physical interaction with solid materials (i.e. heterogeneous surface recombination) does not depend much on the sample temperature, the chemical interactions (functionalization, etching, oxidation) increase significantly with increasing temperature. The key treatment parameters are therefore the fluence of O atoms onto the sample surface and its temperature. The recommended ranges of parameters for various technologies are shown in the graphical abstract. [ABSTRACT FROM AUTHOR]

The technology of selective plasma etching was applied in order to study particle distribution in powder coatings. Etching was performed in pure oxygen plasma. Plasma parameters were measured with a double Langmuir probe and a catalytic probe. At the neutral gas temperature of approximately 50 °C, the electron temperature was approximately 60 000 °C, the density of positive ions approximately 1×1016 m-3, and the density of neutral oxygen atoms 2×1021 m-3. In order to prevent sample overheating, plasma was applied in time intervals of 20 s. The removal of the polymer matrix was accomplished within 2–4 min. After plasma treatment, the samples were analyzed with a scanning electron microscope. All the pigment and filler particles were left intact thus enabling the determination of the original distribution of the particles in the coating. [Copyright &y& Elsevier]