Investigation of Surface Etching of Poly(Ether Ether Ketone) by Atmospheric-Pressure Plasmas

Abstract

An atmospheric-pressure argon plasma jet with varying admixtures of molecular oxygen was used to study the etching mechanism of poly(ether ether ketone) (PEEK). Furthermore, a correlation between plasma-based etching processes on PEEK with the generation of chemically reactive plasma species is proposed. The surface analysis was performed by X-ray photoelectron spectroscopy, atomic force microscopy, and surface profilometry which showed a dramatic increase in the content of oxygen functionalities and surface roughness after long-time Ar/O 2 -plasma treatment. For the plasma diagnostics, two-photon absorption laser-induced fluorescence spectroscopy was applied. The obtained etching mass as well as the surface roughness for different molecular oxygen admixtures revealed a strong dependence on the atomic-oxygen density. Furthermore, the radial surface profile, affected by plasma etching, might be attributed to the distribution of plasma-generated oxygen species in the plasma jet effluent.

Surface modification of polymeric materials by cold atmospheric plasma jet

“…Now not only the ozone but also some short-living active species, such as, atomic oxygen and OH radical may interact with the central part of the substrate leading to an enhanced hydrophilicity. As shown in [14,36] the atomic oxygen can actually spread up to 2.0-2.5 mm way from the plasma column. The computer modeling of active species generated by Ar plasma jet in [31] predicted that along the gas flow oxygen atoms could cover even larger distances (∼ cm).…”

“…The main processes responsible for surface modification of polymers by atmospheric plasmas are hydrogen abstraction, surface etching and incorporation of polar groups [14][15][16]. Cross-linking of plasma-created radials on the polymer surface is also possible.…”

“…In the case of plasma jets, the exited and ionized argon atoms from the discharge create reactive species (mostly atomic oxygen, ozone and OH radical [32,36]) by reaction with the ambient air. These highly reactive species can etch polymers and roughen their surface [14,36]. The AFM images of the untreated PP and the polymer samples treated by APPJ at different processing time are presented in Fig.…”

“…The gas temperature of plasma jets was estimated by various diagnostic methods [12,13] showing that if jet operation conditions were properly chosen the gas temperature at the tip of the plasma plume could be quite low (around room temperature). The plasma jets are particularly useful for material treatment, since the gas flow from the jet guides the reactive species close to the surface where they cause surface etching and functionalization [14,15]. Another advantage of the atmospheric pressure plasma jets (APPJs) is that they are not confined by physical walls, thereby making the treatment of irregular-shaped 3D objects possible [16].…”

Real time characterization of polymer surface modifications by an atmospheric-pressure plasma jet: Electrically coupled versus remote mode

“…Previous work on APPJ surface interaction has not systematically distinguished between the two interaction modes described here, despite substantial difference in the physical mechanisms, and have primarily been investigated post-treatment through methods such as biological deactivation, 6 water contact angle, 7 atomic force microscopy, 8 Fourier transform infrared spectroscopy, 9 and profilometry. 10 In this work, we use a combination of in situ techniques including real time ellipsometry and high speed photography with post characterization techniques. We find that APP source/sample geometry, feed gas, environmental chemistry, and APP source temperature play important roles in determining the consequences of the APP-surface interactions.…”