Applications of highly non-equilibrium low-pressure oxygen plasma for treatment of polymers and polymer composites on an industrial scale

Abstract

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.

Plasma Activation of Polyethylene Powder

“…Super-hydrophilic surface finish (WCA below a few degrees) of PE has never been reported in scientific literature, indicating that the combined effect of saturation with highly polar functional groups and rich morphology on a sub-micrometer scale has never been obtained for this particular polymer. However, the achievable hydrophilicity was found good enough in many practical applications [ 8 ].…”

Recent Advances in Surface Activation of Polytetrafluoroethylene (PTFE) by Gaseous Plasma Treatments

“…Many authors found large differences in plasma parameters upon a slight change of discharge parameters due to non-linear effects, and mainly due to the influence of gaseous impurities on the plasma parameters. The interaction of gaseous plasma with polymer materials has been a subject of numerous scientific studies, and the results were found useful in the optimization of industrial-size reactors [ 8 , 9 , 10 , 11 ].…”

Surface Modification of Polyamides by Gaseous Plasma—Review and Scientific Challenges

“…The etching at a reasonable temperature (preferably close to the room temperature) is a slow process since the etching rate is often the order of nanometers per second [ 45 , 46 ]. The combination of rich surface morphology and high concentration of polar functional groups is usually observed only for polymers treated by low-pressure plasma [ 46 , 47 ]. Surprisingly, most authors concentrated their research on atmospheric-pressure plasmas, although they rarely enable a super-hydrophilic surface finish.…”