Impact of atmospheric pressure nonequilibrium plasma discharge on polymer surface metrology

Abstract

Due to the attraction of plasma technologies as a clean and efficient means of surface modification, significant research has gone into the physical and chemical aspects of polymer functionalization. In this study, it was shown that the use of an atmospheric plasma jet can efficiently modify the surface of polyethylene terephthalate samples and change their hydrophobic properties to more hydrophilic characteristics. The dependence on the changes with respect to time, distance, and atomic oxygen (O I) intensity were considered as factors. It was found that with closer proximity to the plasma source (without causing thermal degradation) and with increasing levels of O I, that the changes of water contact angle and surface free energy can be maximized. It was also observed that the electron energy distribution function, for a given chemistry, significantly differed with changes in distance from the jet nozzle. This shows that for this type of plasma jet system, the bulk of the chemical reactions occur in the nozzle of the jet and not in the surrounding atmosphere. Therefore, this leads to more efficient energy transfer, higher gas temperatures, and better surface activation of samples when compared to systems that produce external chemical reactions due to more diffusion in the surrounding atmosphere and loss of reactive species to other atoms and molecules that are present.

Impact of plasma jet geometry on residence times of radical species

“…Our work includes 12 plasma jets in a circular geometry sufficiently large for many industrial applications. 30 For most commercial plasma jet systems, 29,[31][32][33] the distance between the sample surface and the plasma plume, and the plasma treatment time are critical parameters. In addition, the plasma plume temperature gradient and limited carrier gas chemistry reduce the amount of specific reactive species to interact with the sample surface.…”

“…There are several atmospheric plasma jet systems used by the scientific community. Most of them are conical and come to a point, 29,31,33 but there are linear designs which can be seen with the SurFx 32 system that has a broad plasma jet (around 50 mm). Their common characteristics include a plume which is on the order of centimeters and the diffusion of reactive species rapidly to ambient air.…”

“…Therefore, plasma treatment by the 12-jets system would not significantly depend on the sample's position or treatment time, contrary to other plasma jet technologies. 29,[31][32][33] In Fig. 5, the total intensity represents a collection of spectral radiation form all species in the plasma.…”

Study of the Effect of the Field Emission on the Breakdown Voltage Characteristic of Direct Current Nitrogen Microdischarges

“…Microdischarges are characterized by their small size dimensions and high gas pressures yielding nonequilibrium plasmas [1][2][3][4][5]. Microdischarges have a huge potential in a wide range of future applications like display or photonics technology, embedded sensors, sources of UV light, and surface treatments [6][7][8][9].…”

Spectroscopic study of excited molecular nitrogen generation due to interactions of metastable noble gas atoms

“…Plasma interaction with sample surfaces can cause surface modification, functionalization, sputtering, and etching. Examples include atomic etching of circuits or deposition of oxygen species onto polymers . Furthermore, when used on organic samples, the introduction of oxygen or nitrogen containing radicals can sterilize surfaces due to an increase of reactive oxygen and nitrogen species that cause stresses within organic matter, which leads to degeneration.…”