Pressure Plasma Technology Research Articles

High-Speed Removal Process for Organic Polymers by Non-Thermal Atmospheric-Pressure Spark Discharge at Room Temperature and Its Mechanism

Heel marks (HMs) are a type of dirt stain consisting of polyester-based urethane rubber on polyvinyl chloride (PVC) floor surfaces. The rapid removal of HMs was achieved by using non-thermal atmospheric-pressure plasma technology. Mimetic HMs were prepared by coating PVC floor samples with HMs to a thickness of 13.9 μm. The removal area, thickness, and volume were measured after applying spark discharges at high voltage and a repetition rate of 50 kHz. The treated surfaces were analyzed by using X-ray photoelectron spectroscopy (XPS) and pyrolysis–gas chromatography with time-of-flight mass spectrometry (Py-GC/TOFMS). Removal rates of 20 mm2/min in area, 52 mm3/min in volume, and 7 μm/min in depth were achieved with an inter-electrode distance of 10.0 mm and an air flow rate of 20 standard liters per minute. A removal depth of 10 μm/min was achieved without air supply. The mechanism of stain removal by spark discharge was modeled by decomposing the original high-molecular-weight molecules in polyester-based urethane rubber into low-molecular-weight molecules, such as methylene diisocyanate (MDI) components. The results of this study may facilitate the development of a novel electric vacuum cleaner capable of removing floor stains.

Cold atmospheric pressure plasma assisted rapid assembly of peptide-based structures: a molecular scaffold to form supramolecular architectures

The use of cold atmospheric pressure plasma (CAPP) technology in the production of peptide-based materials has shown great potential in modern technology. Herein, two aggregation-prone oligopeptides, GNNQQNY and KLVFFA, were subjected to CAPP treatment to form supramolecular assemblies/aggregates. Through peptide engineering and biophysical techniques, the effect of CAPP-generated reactive oxygen and nitrogen species on the oligopeptides were investigated for different treatment times revealing that the formation of these aggregates were primarily driven by electrostatic interactions without any chemical modifications. Field emission-scanning electron microscopy and Thioflavin T (ThT) binding assay confirmed the presence of distinct β-strands, particularly in the aggregates of the KLVFFA peptide upon CAPP irradiation. The combination of CAPP technology with peptide self-assembly process and the characterization techniques employed in this study holds promise for the development of such peptide supramolecular structures based on the specific amino acid sequences.

Generation of Plasma-Activated Fluids for Successful Disinfection of Pseudomonas aeruginosa in Liquid Environments and Determination of Microbial Damage

The application of the non-thermal atmospheric pressure plasma technology is a promising tool for microbial inactivation. During the activation process, many reactive substances and radicals arise associated with physicochemical changes in the fluid and massive pH drop. In this study, we analyzed and optimized plasma activation settings and conditions of water and liquids to obtain inactivation of the waterborne microorganism Pseudomonas aeruginosa in a liquid environment. The minimal electrical output was 60 Watt with 20 min activation time followed by 30 min contact time with 108 cells/mL. Using higher electrical power (>90 W) with a Lab Unit generating plasma-activated water, a shorter activation time (<10 min) was sufficient for bacterial inactivation. The organic and inorganic composition of the activated liquid with different mineral salt concentrations is of utmost importance for the yield of reactive species during the plasma activation process and consequently for the antimicrobial effect. Plasma-activated fluids with high organic and inorganic contents demonstrated lower inactivation efficiencies than low loaded fluids; yet antimicrobial efficacy could be achieved by increasing the electrical power and activation time. For sufficient inactivation of bacterial suspensions, at least half a volume unit of plasma-activated water had to be added after appropriately optimized activation. Further dilutions reduced the antimicrobial effect. PAW lost activity after being left standing for a prolonged time after activation, so for maximizing the antimicrobial effect a direct use after activation is recommendable. Bacterial inactivation was shown by the absence of colony forming units on culture media and, at the molecular level, damage to the membrane and inactivation of enzymes were observed. Plasma-activated fluids demonstrated a high potential in applications as microbiological disinfectant in liquids.

Cold atmospheric pressure air plasma jet disinfection of table eggs: Inactivation of Salmonella enterica, cuticle integrity and egg quality

Eggshell cuticles are first lines of defense against egg-associated pathogens, such as Salmonella enterica serovar Enteritidis (SE). Infections from eggs contaminated with this strain remain a significant risk. In addition, changes in the cuticle are closely related to changes in egg safety. The emerging non-thermal atmospheric pressure plasma technology enables a high rate of microbial inactivation at near-ambient temperatures, making it ideal for food safety applications. This study examines the effects of a cold atmospheric pressure air plasma jet (CAAP-J) on eggshell cuticle and egg quality whilst inactivating SE. Shell eggs inoculated with SE (7 log10 cfu/egg) were used as the samples to test the decontamination performance of the device. The tests were conducted using an industrial CAAP-J with different power levels (600–800 W), exposure times (60–120 s), at a fixeddistance of 20 mm from the plasma jet and an air flow rate of 3600 L/h. It was found that the best results were obtained after 120 s at maximum plasma power (800 W). Subsequent to the implementation of this plasma procedure, it was determined that no viable cells could be detected. After CAAP-J treatment, the temperature remains below 50.5 °C, thereby minimizing the risk of altering egg quality. All specific measurements (egg white pH, yolk pH, yolk color, HU, and eggshell breaking strength) have shown that CAAP-J treatment has no negative effect on egg quality. No changes in eggshell cuticle quality after CAAP-J treatment was confirmed through scanning electron microscope (SEM).

Assessment of Cold Atmospheric Pressure Plasma (CAPP) Treatment for Degradation of Antibiotic Residues in Water.

The presence of antibiotic residues in water is linked to the emergence of antibiotic resistance globally and necessitates novel decontamination strategies to minimize antibiotic residue exposure in both the environment and food. A holistic assessment of cold atmospheric pressure plasma technology (CAPP) for β-lactam antibiotic residue removal is described in this study. CAPP operating parameters including plasma jet voltage, gas composition and treatment time were optimized, with highest β-lactam degradation efficiencies obtained for a helium jet operated at 6 kV. Main by-products detected indicate pH-driven peroxidation as a main mechanism of CAPP-induced decomposition of β-lactams. No in vitro hepatocytotoxicity was observed in HepG2 cells following exposure to treated samples, and E. coli exposed to CAPP-degraded β-lactams did not exhibit resistance development. In surface water, over 50% decrease in antibiotic levels was achieved after only 5 min of treatment. However, high dependence of treatment efficiency on residue concentration, pH and presence of polar macromolecules was observed.

Synthesis and characterization of magnesium oxide nanoparticles by atmospheric non-thermal plasma jet

The invention of the system which facilitates and assures the use of atmospheric-pressure plasma technology has been used in several fields, including medicine and nanotechnology. In our work, magnesium oxide (MgO) nanoparticles (NPs) were created using a high voltage power supply of 21 ​kV at high-frequency equipment that produced a 6 ​kHz output. MgO NPs were successfully created at various times. X-Ray Diffraction (XRD) analysis showed that MgO NPs have a polycrystalline and an average crystalline size of 9.365 and 14.253 ​nm in both preparation times (10 and 12 ​min). Additionally, field emission scanning electron (FE-SEM) images show the single nanoparticles appear flake-like, with a thickness of 10 ​nm at 500 ​nm magnification and a width of 20 ​nm. Transmission Electron Microscopy (TEM) was employed to analyze the homogeneous, compact, and dense surface of the produced MgO NPs. Transmission electron microscopy (TEM) analysis showed that the MgO nanoparticle's average diameter ranged from 6 to 18 ​nm. Atomic Force Microscopy (AFM) was also used to uncover the degree of cooperation between the surfaces of MgO NPs, and the results showed a high extraordinary topographic contrast of the MgO NPs with a surface roughness of 2.170 ​nm.

Effects of plasma-activated Ringer’s lactate solution on cancer cells: evaluation of genotoxicity

BackgroundNon-thermal atmospheric pressure plasma technologies form the core of many scientific advances, including in the electronic, industrial, and biotechnological fields. The use of plasma as a cancer therapy has recently attracted significant attention due to its cancer cell killing activity. Plasma-activated Ringer’s lactate solution (PAL) exhibits such activity. In addition to ROS, PAL contains active compounds or species that cause cancer cell death, but the potential mutagenic risks of PAL have not been studied.ResultsPAL has a low pH value and a high concentration of H2O2. H2O2 was removed from PAL using catalase and catalase-treated PAL with a pH of 5.9 retained a killing effect on HeLa cells whereas this effect was not observed if the PAL was adjusted to pH 7.2. Catalase-treated PAL at pH 5.9 had no significant effect on mutation frequency, the expression of γH2AX, or G2 arrest in HeLa cells.ConclusionPAL contains one or more active compounds or species in addition to H2O2 that have a killing effect on HeLa cells. The compound(s) is active at lower pH conditions and apparently exhibits no genotoxicity. This study suggested that identification of the active compound(s) in PAL could lead to the development of novel anticancer drugs for future cancer therapy.

The Efficacy and Safety of The Innovative Cold Atmospheric-Pressure Plasma Technology in The Treatment of Striae Distensae: A Randomized Controlled Trial.

Available current therapeutics modalities for striae distensae (SD) provide inconsistently effective outcomes. There is ongoing research on innovative treatment modalities to find better treatment solutions. To evaluate the efficacy and safety of innovative cold atmospheric plasma (CAP) technology in the treatment of striae distensae METHODS: This study includes twenty-three patients with striae distensae. The body was divided into two halves. One side was randomly treated with CAP biweekly on the same treated side for five sessions with 30 days follow-up after the last session. Another half was left untreated. Efficacy assessment was done using POSAS, patient satisfaction scales, and Antera 3D® skin imaging system. Safety assessment was evaluated using the visual analog scale (VAS) and adverse effects monitoring. POSAS, patient and observer overall opinion score, and patient and observer total score in a summary of all rated characteristics, comparing treated and untreated areas, showed a statistically significant reduction in all parameters after one treatment (*P-value < 0.05). Patients rated satisfaction as a great improvement in 52.3%, moderate improvement in 39.1%, extreme improvement in 4.3%, and slight improvement in 4.3%. Adverse effects included small scabs, shallow wounds, and rash. CAP is a safe and effective, innovative treatment modality for striae distensae with minimal side effects.

Robotised atmospheric plasma treatment to improve the adhesion of vulcanised and thermoplastic rubber materials for a more sustainable footwear

Surface treatment is essential to ensure the resistance and durability of adhesive upper-to-sole joints for footwear. This study investigates robotised atmospheric pressure plasma technology to increase adhesion on styrene-butadiene vulcanised (SBR) and styrene-butadiene-styrene thermoplastic (SBS) rubbers, which constitutes a more sustainable surface treatment as an alternative to solvent-based chemical treatments (i.e., halogenation). In this work, the different parameters such as application speed and distance of the nozzle of the atmospheric plasma system have been optimised and the effects of the plasma treatment on the physicochemical properties in the materials’ surface, roughness, wettability, as well as the adhesion properties have been evaluated by means of different experimental techniques: Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Photoelectron Spectroscopy (XPS), Field Emission Scanning Electron (FESEM), Contact Angles (CA) and Surface Free Energy (SFE) measurements and T-peel strength tests. The results show that the values obtained for the T-peel strength of the reactive hot melt polyurethane adhesive (HMPUR) joints studied exceed the minimum quality requirements for footwear according to standardised tests. In consequence, the optimisation and validation of operating plasma conditions and adhesion properties of rubbers could consolidate atmospheric plasma as a solvent-free alternative for the preparation of footwear soling materials. The great advantage of this technology is its introduction into the production line by fully automating the bonding process with the use of robots.

Plasma Nanocoating of Nonwovens

SummaryLow pressure plasma polymerization is a unique technology to deposit ultrathin coatings on all exposed surfaces of a material or product. It is increasingly used in the manufacturing of nonwo‐vens to achieve functionalities such as hydrophilic, hydrophobic, oleophobic or dielectric. Improvements in process and machine design allow to deposit the coatings in a very cost effective way, with a process that is completely dry and clean. The article will start with a short introduction of low pressure plasma polymerization technology. Then it will review industrial concepts for both batch and roll‐to‐roll treatment. An overview will be given of typical coating chemistries used for such coatings. Subsequently recent advances will be discussed using real industrial case studies. The article will conclude with an overview of the societal and environmental benefits of low pressure plasma technology.

Atmospheric Pressure Plasma in Industrial Applications: Surface treatment of thermally sensitive polymers

AbstractFor several years now, atmospheric pressure plasma has been discussed as a future technology. It is a key technology with a long and successful past. For many decades, corona treatment has been an atmospheric pressure plasma application, well established within the extrusion and converting industry. Corona technology has been applied in industrial use since the 1950s, mostly within converting polymer films and to some degree paper, board, and metal foil. Corona treatment is used to improve the adhesion of printing inks, lacquers, adhesives, and coatings. From this strong base, atmospheric pressure plasma is growing into new applications. This paper introduces atmospheric pressure plasma basics and compares modern atmospheric pressure plasma technologies for grafting chemical functional groups on polymer surfaces.

Human coronavirus inactivation by atmospheric pressure helium plasma

The recent global pandemic of Corona Virus Disease-19 has impacted all aspects of society, producing a growing demand for a powerful virus inactivation method. To assess a potential and mechanism of human coronavirus inactivation using atmospheric pressure plasma (APP) technology, replication of a human coronavirus (HCoV-229E) after He + H2O APP plume exposure was evaluated using rhesus monkey kidney epithelial cells. The HCoV-229E titers were reduced by 3 log10TCID50 after the APP exposure for 30 s, showing a strong virus-inactivation efficacy of the APP. It was experimentally verified that the APP produced the liquid-phase reactive oxygen and nitrogen species (RONS) at high rates [e.g. •OH: ∼1.7 nmol s−1, H2O2 (including H2O2 precursors): ∼9.2 nmol s−1, NO2 − (including NO2 − precursors): ∼3.3 nmol s−1]. However, an administration of H2O2 with NO2 − failed to inactivate the virus and only Mn type superoxide dismutase among several RONS scavengers for •OH, HO2 •/O2 •−, 1O2, and •NO/•NO2 was significantly effective for the recovery of the APP-induced decrease in the viral titers. This suggests O2 •−-related chemical reaction in a network of interconnected reactions induced by the APP exposure is very important for the APP-induced virus inactivation. These results provide new insight into a more efficient inactivation method of human coronavirus using APPs.

Nanosecond-scale impulse generator for biomedical applications of atmospheric-pressure plasma technology.

This study proposes an improved high-voltage fast impulse generator based on an inductive energy storage system with a 4kV static induction thyristor. Nanosecond-scale impulses with pulse widths below 100ns and a peak voltage of up to 15kV can be generated by modifying the high-voltage transformer in the circuit and tuning the circuit capacitor. The resulting device is highly stable and can perform continuously if the discharge parameters are chosen within the recommended range. A plasma jet was operated using the generator at low temperature (below 37 °C). Together with its high stability and potential for continuous operation, the proposed generator offers promise for use in biomedical and agricultural applications. Furthermore, the nanosecond-scale high-voltage impulses produced by the generator enable it to achieve an electron density in the plasma one order of magnitude higher than the commercially available radio frequency plasma jet analog. We also show how to reduce the total cost of the generator.

In vivo Assessment of Cold Atmospheric Pressure Plasma Technology on the Bioactivity of Spirulina.

The present study challenges the in vivo assessment of cold atmospheric pressure plasma (CAPP) technology on the bioactive activity (antioxidant/antiaging and antimicrobial potential) of Spirulina powder, using Caenorhabditis elegans as an animal model. Surface microdischarge cold atmospheric pressure plasma (SMD-CAPP) treatment was 3.3 W discharge power for 7 min. C. elegans lifespan and egg laying were used as indicators of antioxidant/antiaging potential of Spirulina (1 mg/mL), when grown with Spirulina CP-treated [E_SCP] and untreated [E_S], compared with a control [E_0] (non-supplemented with Spirulina). According to our results, under both Spirulina supplemented media [E_SCP and E_S] and for the first 17 days, nematodes experienced an increase in lifespan but without significant differences (p > 0.05) between control and Spirulina CP-treated. Regarding the in vivo assay of the antimicrobial potential of Spirulina against Salmonella enterica serovar Typhimurium (infected worms), no significant differences (p > 0.05) were found between the three exposure scenarios (control [S_0]; Spirulina supplemented media [S_S]; CP-treated Spirulina supplemented media [S_SCP]). According to present results, CAPP-treatment do not influence negatively the lifespan of C. elegans but a reduction in the Spirulina antiaging potential was found. No in vivo modifications in antimicrobial activity seem to be linked to CAPP-processed Spirulina.

Review of Plasma Technologies for Contribution of Environmental Purification

Since the beginning of the 20th century, plasma technology has been used in a variety of fields. In the 1980s, R&D related to arc plasma welding and waste disposal, as well as etching, painting, and gas removal equipment that used plasma technology in the processes associated with semiconductor manufacturing. In the 1990s, research on removing air pollutants using atmospheric pressure plasma technology became active. In the 2000s, research on the application of thermal/non-thermal plasma technology to air pollution, waste and water treatment became active. Electrostatic precipitators (ESP) can remove a wide variety of particles such as soot from thermal power plants, coal, and oil mist, resin powder, glass powder, dust, and iron powder generated from incinerators, boilers, and various manufacturing plants. Waste treatment aims to reduce the volume of garbage, recycle incinerated materials, and utilize waste heat from incineration, and plasma technology is used in each process. Various techniques have been used for making purified water. Water quality requirements vary according to the objective. Plasma technology uses an electrical field to encourage seed germination and growth. Due to the spread of such applied technology, plasma technology has attracted attention again in recent years.

Review on recent advances in cold plasma technology

This paper reviews the technological advancements of cold atmospheric pressure plasma technology (CAPPT) in various fields that include medicine, agriculture, and industry. In recent years, cold plasma technology has received considerable interest due to its inherent benefits that include- free radicals for inactivation of microbes, eco-friendliness, cheap operational cost, simplicity of operation, and portability of devices. Various working gases (nitrogen, argon, and helium) and various mechanisms (dielectric barrier discharge, corona discharge, floating electrodes) have been implemented for generating cold plasma at room temperature. Overall CAPPT technology has proved to be an efficient and potent tool offering both technological and biomedical applications.

Generation and Characterization of Cold Atmospheric Pressure Plasma Jet for Surface Modification of High-Density Polyethylene

Cold atmospheric pressure plasma technology has a variety of applications in different fields including material science and biomedical science. It has been using for surface modification and material processing in material science and used to improve the wettability, adhesion and biocompability of polymeric surfaces without altering the entire bulk properties. This paper outlines the characterization of cold atmospheric pressure plasma jet, which was generated in a high frequency (20 kHz) and high voltage (3.5 kV) power supply, as well as its application in the surface modification of high density polyethylene. Electrical and optical characteristics are used to estimate the electron density of the plasma. The effect of plasma on the surface properties of the material are analyzed by calculating contact angle, surface energy measurements and analyzing scanning electron microscopy images. Adhesive bonding strength and numerous other attributes have increased, however surface treatment is the process of cleaning, etching, functionalizing, and chemically treating substrates to improve roughness and adhesive properties on the surface. Cold plasma can induce a soft roughening on the surface through ion bombardment with polar functional groups resulting in the decrease in water contact angle.

Low-Temperature Atmospheric Pressure Plasma Processes for the Deposition of Nanocomposite Coatings

Low-temperature atmospheric pressure (AP) plasma technologies have recently proven to offer a range of interesting opportunities for the preparation of a variety of nanocomposite (NC) coatings with different chemical compositions, structures, and morphologies. Since the late 2000s, numerous strategies have been implemented for the deposition of this intriguing class of coatings by using both direct and remote AP plasma sources. Interestingly, considerable progress has been made in the development of aerosol-assisted deposition processes in which the use of either precursor solutions or nanoparticle dispersions in aerosol form allows greatly widening the range of constituents that can be combined in the plasma-deposited NC films. This review summarizes the research published on this topic so far and, specifically, aims to present a concise survey of the developed plasma processes, with particular focus on their optimization as well as on the structural and functional properties of the NC coatings to which they provide access. Current challenges and opportunities are also briefly discussed to give an outlook on possible future research directions.

광전자 소자 및 이차전지 소재로 페로브스카이트 반도체 막을 적용하기 위하여 질소 상압플라즈마 기술을 적용한 표면 처리 연구

Perovskite materials have recently been intensively studied because of their excellent optical properties. However, when this material is exposed to air, there is a problem in that properties deteriorate. In this paper, we investigated whether such deterioration can be restored to its original characteristics by using nitrogen atmospheric pressure plasma technology. In order to observe the return to the original coated film, the experiment was conducted as follows. After coating the perovskite semiconductor material, when exposed to air for about 6 months, some grains are lifted due to contact with oxygen or water vapor, and holes are also observed. In order to restore these grain changes to the originally formed film, the surface of the semiconductor material was treated from 5 s to 1200 s using nitrogen plasma. The surface-treated samples were observed by SEM, EDS, and AFM analysis techniques. As a result of observing the surface shape using SEM, the flotation or hole disappeared for 5 seconds and 10 seconds, and the same surface shape as the deposited film was shown. However, in the film treated for 30 to 60 seconds, the thin film is gradually removed by nitrogen plasma. Under the condition of 180 seconds or more, a number of islands are very densely distributed rather than the form of a film. According to the AFM analysis, the surface roughness of the sample exposed to air for 180 days was about 14.724nm, but it can be seen that the roughness value was significantly reduced to 1.6338nm for the film that was processed for 5 seconds. A solar cell device was fabricated using the film exposed to air for 6 months and the surface-treated film. Nitrogen plasma treatment confirmed the improvement of degraded thin film properties. These results suggest the possibility of restoration even if the perovskite thin film degrades due to exposure to the air in the future.

Degradation of toluene in surface dielectric barrier discharge (SDBD) reactor with mesh electrode: Synergistic effect of UV and TiO2 deposited on electrode

Combing with photo-catalysis and photo-catalyst, a surface dielectric barrier discharge (SDBD) reactor with a mesh electrode was applied for toluene degradation and a high mineralization was achieved. The degradation performance comparison between SDBD reactors with a mesh and a spring electrode was carried out as well. A significant improvement in carbon balance and CO2 selectivity were obtained in mesh SBDB reactor compared with that of spring's one. For instance, when only plasma was applied, the carbon balance and CO2 selectivity of mesh SDBD reactor were 84% and 42.6%, while only 64.5% and 31.8% in spring one, the carbon balance and CO2 selectivity were improved by 30.3% and 34% at SIE of 300 J L−1, respectively. Synergistic effects of photo-catalysis and photo-catalyst were conducted with a 254 nm UV lamp and TiO2 deposited on the mesh electrode by atmospheric pressure (AP) plasma technology. The results showed that TiO2 and UV irradiation both presented promoting effect on toluene degradation in SDBD reactor with mesh electrode. According to the experimental results, the carbon balance rose to 89.5% and 93.9% at SIE of 300 J L−1, when UV or TiO2 was applied. With the application of TiO2 and UV together, a highest carbon balance of 95.9% was obtained at the same SIE. At the same SIE, the CO2 selectivity was promoted by 42.8% or 55.3% with the application of UV or TiO2, and the promotion finally reached at 59.1% when TiO2 and UV were applied together. Additionally, the degradation efficiency of toluene was also enhanced with the introduction of TiO2 and UV irradiation. Increases in toluene degradation efficiency of 19. 7% and 26.8% were obtained at SIE of 300 J L−1, respectively. When both TiO2 and UV were applied, the enhancement could rise to 41.6%.