scholarly journals Investigation of Surface Modification of Polystyrene by a Direct and Remote Atmospheric-Pressure Plasma Jet Treatment

Materials ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2435
Author(s):  
Alenka Vesel ◽  
Gregor Primc

Localized functionalization of polymer surface with an atmospheric-pressure plasma jet was investigated at various treatment conditions. Polystyrene samples were treated with the plasma jet sustained in argon under direct or remote conditions. The two-dimensional evolution of surface wettability and the spot size of the treated area was determined systematically by measuring apparent water contact angles. Modification of surface chemistry and the formation of functional groups were investigated by X-ray photoelectron spectroscopy (XPS). The saturation of surface wettability and functional groups was observed even after a second of treatment providing the sample was placed close to the exhaust of the discharge tube. The spot diameter of the modified area increased logarithmically with increasing treatment time. However, it decreased linearly when increasing the distance. At the edge of the glowing plasma, however, the modification of surface properties was more gradual, so even 30 s of treatment caused marginal effects. With a further increase in the distance from the edge of the glowing plasma, however, there were no further treatment effects. The results are explained by significant axial as well as radial gradients of reactive species, in particular hydroxyl radicals.

Author(s):  
RB Tyata ◽  
DP Subedi ◽  
A Shrestha ◽  
D Baral

In this paper, an atmospheric pressure plasma jet (APPJ) in air that is expected to be useful for polymer surface modification has been reported. The plasma jet was produced by applying (10 - 30) kHz, (0 - 20) kV AC source. The electrical and optical measurements have also been reported. The use of solenoid as an external electrode has been found to be more effective in boosting the jet to a distance up to 30 mm even with a small flow rate of air. The characteristic of the proposed APPJ was investigated by measuring the effect of treatment on a PE film on the jet for different exposition time and distance from the nozzle. It has been confirmed that the jet can modify polymer film with a work distance of over 25mm. This plasma jet can be useful for the treatment and cleaning of objects having large structures and could be used in wider areas of application. DOI: http://dx.doi.org/10.3126/kuset.v8i1.6035 KUSET 2012; 8(1): 15-22


Processes ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 1134
Author(s):  
Khattiya Srakaew ◽  
Artit Chingsungnoen ◽  
Waraporn Sutthisa ◽  
Anthika Lakhonchai ◽  
Phitsanu Poolcharuansin ◽  
...  

This work aims to develop a multihole atmospheric pressure plasma jet (APPJ) device to increase the plasma area and apply it to a continuous seed treatment system. Broccoli seed was used to study the effects of an atmospheric pressure plasma jet on seed germination and growth rate. An argon flow rate of 4.2 lpm, a plasma power of 412 W, and discharge frequency of 76 kHz were used for seed treatment. The contact angle decreased strongly with the increase in treatment time from 20 s to 80 s. The broccoli seed’s outer surface morphology seemed to have been slightly modified to a smoother surface by the plasma treatment during the treatment time of 80 s. However, the cross-sectional images resulted from Synchrotron radiation X-ray tomographic microscopy (SRXTM) confirmed no significant difference between seeds untreated and treated by plasma for 80 s. This result indicates that plasma does not affect the bulk characteristics of the seed but does provide delicate changes to the top thin layer on the seed surface. After seven days of cultivation, the seed treated by plasma for 30 s achieved the highest germination and yield.


Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 87 ◽  
Author(s):  
Alenka Vesel ◽  
Rok Zaplotnik ◽  
Gregor Primc ◽  
Miran Mozetič

A useful technique for pre-treatment of polymers for improved biocompatibility is surface activation. A method for achieving optimal wettability at a minimal thermal load and unwanted modifications of the polymer properties is elaborated in this paper. Samples of polyethylene terephthalate polymer were exposed to an atmospheric-pressure plasma jet created by a high-impedance low-frequency discharge in wet argon. Different treatment times and distances from the end of the glowing discharge enabled detailed investigation of the evolution of surface activation. A rather fast saturation of the surface wettability over the area of the order of cm2 was observed upon direct treatment with the glowing discharge. At a distance of few mm from the glowing discharge, the activation was already two orders of magnitude lower. Further increase of the distance resulted in negligible surface effects. In the cases of a rapid activation, very sharp interphase between the activated and unaffected surface was observed and explained by peculiarities of high-impedance discharges sustained in argon with the presence of impurities of water vapor. Results obtained by X-ray photoelectron spectroscopy confirmed that the activation was a consequence of functionalization with oxygen functional groups.


Plasma ◽  
2022 ◽  
Vol 5 (1) ◽  
pp. 44-59
Author(s):  
Gerrit Wulf ◽  
Bernd Mayer ◽  
Uwe Lommatzsch

Plasma co-polymers (co-p) were deposited with an atmospheric pressure plasma jet (APPJ) using a precursor mixture containing hexamethyldisiloxane (HMDSO) and limonene. A coating with fragments from both precursors and with siloxane, carbonyl and nitrogen functional groups was deposited. The flow rate of limonene was found to be an important parameter for plasma co-polymerization to tune the formation and structure of the functional groups. The FTIR and XPS analysis indicates that with increasing flow rate of limonene a higher proportion of carbon is bound to silicon. This is related to a stronger incorporation of fragments from limonene into the siloxane network and a weaker fragmentation of HMDSO. The formation mechanism of the nitroxide and carboxyl groups can be mainly differentiated into in-plasma and post-plasma reactions, respectively.


Micromachines ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 683
Author(s):  
Huiliang Jin ◽  
Caixue Tang ◽  
Haibo Li ◽  
Yuanhang Zhang ◽  
Yaguo Li

The continuous phase plate (CPP) is the vital diffractive optical element involved in laser beam shaping and smoothing in high-power laser systems. The high gradients, small spatial periods, and complex features make it difficult to achieve high accuracy when manufacturing such systems. A high-accuracy and high-efficiency surface topography manufacturing method for CPP is presented in this paper. The atmospheric pressure plasma jet (APPJ) system is presented and the removal characteristics are studied to obtain the optimal processing parameters. An optimized iterative algorithm based on the dwell point matrix and a fast Fourier transform (FFT) is proposed to improve the accuracy and efficiency in the dwell time calculation process. A 120 mm × 120 mm CPP surface topography with a 1326.2 nm peak-to-valley (PV) value is fabricated with four iteration steps after approximately 1.6 h of plasma processing. The residual figure error between the prescribed surface topography and plasma-processed surface topography is 28.08 nm root mean square (RMS). The far-field distribution characteristic of the plasma-fabricated surface is analyzed, for which the energy radius deviation is 11 μm at 90% encircled energy. The experimental results demonstrates the potential of the APPJ approach for the manufacturing of complex surface topographies.


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