scholarly journals Plasma Surface Modification of Epoxy Polymer in Air DBD and Gliding Arc

Processes ◽  
2022 ◽  
Vol 10 (1) ◽  
pp. 104
Author(s):  
Panagiotis Dimitrakellis ◽  
François Faubert ◽  
Maxime Wartel ◽  
Evangelos Gogolides ◽  
Stéphane Pellerin

We studied the epoxy polymer surface modification using air plasma treatment in a Gliding Arc (GA) plasma reactor and a pulsed Dielectric Barrier Discharge (DBD). We employed optical emission spectroscopy (OES) measurements to approximate the vibrational and rotational temperatures for both plasma sources, as well as surface temperature measurements with fiber optics and IR thermography to corelate with the corresponding hydrophilization of the epoxy material. Water contact angle measurements revealed a rapid hydrophilization for both plasma sources, with a slightly more pronounced effect for the air DBD treatment. Ageing studies revealed stable hydrophilicity, with water contact angle saturating at values lower than 50°, corresponding to a >50% decrease compared to the untreated epoxy polymer. ATR-FTIR spectroscopy studies showed an additional absorption band assigned to carbonyl group, with its peak intensity being higher for the DBD treated surfaces. The spectra were also correlated with the surface functionalization via the relative peak area ratio of carbonyl to oxirane and benzene related bands. According to SEM imaging, GA plasma treatment led to no apparent morphological change, contrary to DBD treatment, which resulted in nano-roughness formation. The enhanced surface oxidation as well as the nano-roughness formation on epoxy surface with the air DBD treatment were found to be responsible for the stable hydrophilization.

2021 ◽  
Vol 11 (4) ◽  
pp. 12227-12237
Author(s):  
Yuri Ferreira da Silva ◽  
Renata Nunes Oliveira ◽  
Renata Antoun Simao

Ivory nuts, bioproducts from South American palms, possess a hard, water-insoluble, and microporous endosperm with a strong resemblance to elephant ivory. The nuts sustainable appeal made them popular as eco-friendly substitutes to ivory and, more recently, microbeads. However, their hygroscopicity and mannan composition impart susceptibility to deterioration by microbes and insects. Cold plasma treatment has been widely investigated as a clean and cost-effective procedure for seed disinfection and surface modification. Hence, in this work, ivory nut endosperm was treated by an air plasma jet to modify wettability. Plasma treated samples were characterized by the water contact angle, AFM, and Raman imaging. Water contact angle results presented an increase from (31.5 ± 8.7)º to (78.9 ± 5.4)º, demonstrating surface hydrophobization. This result was attributed to the modification of surface chemistry by migration and repolymerization of extractives promoted by plasma treatment. AFM results evidenced the formation of a heterogeneous layer containing lamellar features similar to plant epicuticular waxes. Besides, principal component analysis of Raman imaging results highlighted spectral contributions from wax, xylan, mannan, and lignin. These results demonstrate that atmospheric air plasma jets can be employed for ivory nut hydrophobization with no need for additional precursors, altering surface chemistry by crosslinking endosperm native substances.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Andrzej Sikora ◽  
Dariusz Czylkowski ◽  
Bartosz Hrycak ◽  
Magdalena Moczała-Dusanowska ◽  
Marcin Łapiński ◽  
...  

AbstractThis paper presents the results of experimental investigations of the plasma surface modification of a poly(methyl methacrylate) (PMMA) polymer and PMMA composites with a [6,6]-phenyl-C61-butyric acid methyl ester fullerene derivative (PC61BM). An atmospheric pressure microwave (2.45 GHz) argon plasma sheet was used. The experimental parameters were: an argon (Ar) flow rate (up to 20 NL/min), microwave power (up to 530 W), number of plasma scans (up to 3) and, the kind of treated material. In order to assess the plasma effect, the possible changes in the wettability, roughness, chemical composition, and mechanical properties of the plasma-treated samples’ surfaces were evaluated by water contact angle goniometry (WCA), atomic force microscopy (AFM), attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS). The best result concerning the water contact angle reduction was from 83° to 29.7° for the PMMA material. The ageing studies of the PMMA plasma-modified surface showed long term (100 h) improved wettability. As a result of plasma treating, changes in the samples surface roughness parameters were observed, however their dependence on the number of plasma scans is irregular. The ATR-FTIR spectra of the PMMA plasma-treated surfaces showed only slight changes in comparison with the spectra of an untreated sample. The more significant differences were demonstrated by XPS measurements indicating the surface chemical composition changes after plasma treatment and revealing the oxygen to carbon ratio increase from 0.1 to 0.4.


2020 ◽  
Vol 2 (2) ◽  
pp. 48-49

Ivory nuts, produced by palms from the genus Phytelephas, possess a hard and microporous endosperm with a strong resemblance to elephant ivory. The nuts sustainable appeal made them popular as eco-friendly substitutes to ivory since they promote the development of forest communities without contributing to deforestation and animal poaching. In addition, they have been commercialized as microbeads to replace microplastics in cosmetic applications. However, this material is vulnerable to deterioration by micro-organisms and insects, as they are predominantly constituted by β-1,4-mannan, a hydrophilic polysaccharide similar to cellulose. In this context, seed endosperm was treated for 80 s by an atmospheric air plasma jet so as to modify its wettability, as plasma has been widely studied recently for seed disinfection and surface modification. Plasma treated samples were characterized by the water contact angle, AFM, and Raman imaging. Water contact angle results showed an increase from (31.5 ± 8.7)º to (78.9 ± 5.4)º, indicating incorporation of hydrophobic moieties to the sample surface. In turn, AFM images demonstrate the formation of a rough and heterogeneous coating that resembles epicuticular wax layers. Furthermore, principal component analysis of Raman imaging results evidenced contributions from wax (1156, 1170 and 1410 cm-1), carbohydrates (1020, 1080 and 1106 cm-1), and lignin (1573, 1635 and 1662 cm-1). These results indicate that plasma treatment promoted the migration of hydrophobic waxes to the surface and their crosslinking with fragmented cell wall material such as mannan, xylan, and lignin, promoting seed hydrophobization with no need for additional precursors or generation of side products.


2021 ◽  
Vol 22 (13) ◽  
pp. 6672
Author(s):  
Nina Recek ◽  
Matej Holc ◽  
Alenka Vesel ◽  
Rok Zaplotnik ◽  
Peter Gselman ◽  
...  

Seeds of common bean (Phaseolus vulgaris L.), of the Etna variety, were treated with low-pressure oxygen plasma sustained by an inductively coupled radiofrequency discharge in the H-mode for a few seconds. The high-intensity treatment improved seed health in regard to fungal contamination. Additionally, it increased the wettability of the bean seeds by altering surface chemistry, as established by X-ray photoelectron spectroscopy, and increasing surface roughness, as seen with a scanning electron microscope. The water contact angle at the seed surface dropped to immeasurably low values after a second of plasma treatment. Hydrophobic recovery within a month returned those values to no more than half of the original water contact angle, even for beans treated for the shortest time (0.5 s). Increased wettability resulted in accelerated water uptake. The treatment increased the bean radicle length, which is useful for seedling establishment in the field. These findings confirm that even a brief plasma treatment is a useful technique for the disinfection and stimulation of radicle growth. The technique is scalable to large systems due to the short treatment times.


2012 ◽  
Vol 627 ◽  
pp. 791-795
Author(s):  
Ru Li ◽  
Fen Fen Liu ◽  
Ji Fei Deng

The use of low-temperature plasmas to modify the surface of substrates and grafted acrylic acid is discussed. Their surface composition characterized by attenuated total reflectance fourier transform infrared (ATR-FTIR) spectra and water contact angle. The results of various techniques indicated that acrylic acid could be incorporated in the membrane surface. The plasma treatment time,plasma treatment power and grafting time effect on water contact angle. The water contact angle decreased from 67° for virgin PES to 11° for the plasma-induced and 0° for grafted AA.


2013 ◽  
Vol 800 ◽  
pp. 606-609 ◽  
Author(s):  
Ru Li ◽  
Fen Fen Liu ◽  
Ji Fei Deng

The polysulfone membranes surface modification by the low temperature air plasma for the study. The PS membranes surface composition, filtration, antifouling characteristics with the modification was characterized by water contact angle, water fluxes, interception rate. Polysulfone membranes hydrophilic has been greatly improved, by water contact angle decreased significantly with low temperature air plasma treatment .Optimal conditions for plasma processing are power 60W, 1.5min, vacuum 60Pa.The water fluxes for the modified PS were increased 2.3 times than the nascent one, the interception rate was little changed. Membrane pollution gradually increased as the wastewater permeation flux decreased with time.


Plasma ◽  
2021 ◽  
Vol 4 (3) ◽  
pp. 389-398
Author(s):  
Marius Behnecke ◽  
Vincent Steinert ◽  
Svea Petersen

This study investigates the suitability of Piezoelectric Direct Discharge Plasma as a tool for wetting behaviour modification of PEEK and dentin, and compares the results of this method with low-pressure plasma treatment and phosphoric acid etching. Static contact angle measurements were made, roughness was assessed using tactile measurement, and AFM and SEM images were taken. An optimum operating distance of ≤15 mm was determined for the plasma based on the water contact angle. Furthermore, it was demonstrated that despite only a fraction of the power, the PDD plasma also produces hydrophilic and nanostructured PEEK surfaces with a 38° water contact angle in the same plasma time. In contrast, the gold standard of dental surface modification of dentin—phosphoric acid etching—showed no measurable contact angle due to the exposed dentin tubules. Treatment with PDD plasma reduces the water contact angle of dentin from 65° to 43° and is not negative affected by water. Wet, PDD plasma-treated dentin samples show a water contact angle of only 26.5°. The dentin tubules exposed by chemical etching led to a significantly increased roughness. No comparable effect could be demonstrated for plasma treatment on dentin, but based on the contact angle measurements, a chemically strongly activated surface with strongly polar interaction behaviour can be assumed. The additional use of the PDD plasma technique to improve wetting could therefore have a positive effect on the adhesive bond between human dentin and polymeric dental restorative materials or, depending on the adhesive system, replace the etching process altogether.


2009 ◽  
Vol 610-613 ◽  
pp. 1259-1262 ◽  
Author(s):  
Na Ru Zhao ◽  
Ying Jun Wang ◽  
Li Ren ◽  
Xiao Feng Chen

Chitosan membranes were prepared by solvent cast method. In order to increase cell adhesion of the chitosan membranes, oxygen plasma treatment was applied to improve the hydrophilicity of the surface of chitosan membranes. The surface properties were characterized by scanning electron microscopy (SEM), contact angle analyzer, X-ray photoelectron spectroscopy (XPS). The effects of exposure time, plasma generating power, and chamber pressure on water contact angle of the chitosan membranes were investigated. The water contact angle of chitosan membranes decreased from 94.1° to 49.2° after plasma treatment. Which suggested the surfaces became more hydrophilic. XPS analysis showed that the oxygen content and the ratio of O/C increased markedly after oxygen plasma treatment. Furthermore, it was found that C-H bonds were broken with oxygen plasma treatment. C-OH group had been increased after plasma irradiation.


2009 ◽  
Vol 103 (5) ◽  
pp. 845-856 ◽  
Author(s):  
Ilaria Donelli ◽  
Paola Taddei ◽  
Philippe F. Smet ◽  
Dirk Poelman ◽  
Vincent A. Nierstrasz ◽  
...  

2020 ◽  
Author(s):  
Muayad Al-shaeli ◽  
Stefan J. D. Smith ◽  
Shanxue Jiang ◽  
Huanting Wang ◽  
Kaisong Zhang ◽  
...  

<p>In this study, novel <a>mixed matrix polyethersulfone (PES) membranes</a> were synthesized by using two different kinds of metal organic frameworks (MOFs), namely UiO-66 and UiO-66-NH<sub>2</sub>. The composite membranes were characterised by SEM, EDX, FTIR, PXRD, water contact angle, porosity, pore size, etc. Membrane performance was investigated by water permeation flux, flux recovery ratio, fouling resistance and anti-fouling performance. The stability test was also conducted for the prepared mixed matrix membranes. A higher reduction in the water contact angle was observed after adding both MOFs to the PES and sulfonated PES membranes compared to pristine PES membranes. An enhancement in membrane performance was observed by embedding the MOF into PES membrane matrix, which may be attributed to the super-hydrophilic porous structure of UiO-66-NH<sub>2</sub> nanoparticles and hydrophilic structure of UiO-66 nanoparticles that could accelerate the exchange rate between solvent and non-solvent during the phase inversion process. By adding the MOFs into PES matrix, the flux recovery ratio was increased greatly (more than 99% for most mixed matrix membranes). The mixed matrix membranes showed higher resistance to protein adsorption compared to pristine PES membranes. After immersing the membranes in water for 3 months, 6 months and 12 months, both MOFs were stable and retained their structure. This study indicates that UiO-66 and UiO-66-NH<sub>2</sub> are great candidates for designing long-term stable mixed matrix membranes with higher anti-fouling performance.</p>


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