Application Of Atmospheric Pressure Plasma Research Articles

Recent Progress in Applications of Atmospheric Pressure Plasma for Water Organic Contaminants’ Degradation

Recent Progress in Applications of Atmospheric Pressure Plasma for Water Organic Contaminants’ Degradation

Atmospheric pressure plasma application on the adhesive bonding improvement of CFRP via surface configuration comparison

AbstractCarbon fiber reinforced polymer (CFRP) has a wide range of applications in aerospace, automobile, marine, and other industries, due to its remarkable mechanical properties and lightweight. It can enhance the performance of the structural components and has been presented to be a good alternative over conventional materials. Adhesive bonding has been widely employed, and research studies on the surface modification of CFRP have been conducted to improve the load resistance of adhesive bonding, of which atmospheric pressure (AP) plasma is the most preferred method. However, there is still a lack of study on the effectiveness and strategies of AP plasma surface modification. To gain more insight, possible sources that would have influence on the adhesive bonding were analyzed by preparation of different surface configurations of CFRP. It is confirmed that AP plasma can increase the surface polarity and wettability of the carbon fiber surface. It can contribute to the removal of surface contamination element as well. Although the surface morphology and surface roughness before and after the AP plasma treatment does not show noticeable changes, the single‐lap shear strength of the contaminated samples can be effectively improved. This study validates that AP plasma is effective on surface contamination removal and bonding quality improvement, which provides a potential alternative for the adhesive bonding improvement and surface modification of carbon fiber.Highlights Surface polarity and wettability increase of CFRP by AP plasma. Surface contamination removal and bonding quality improvement by AP plasma. AP plasma provides a potential alternative method for adhesive bonding pre‐treatment. AP plasma surface modification mechanism analysis via surface characterization.

Investigation of the effect of atmospheric pressure plasma application on bond strength of POM and PP materials

Polioksimetilen (POM) ve polipropilen (PP) malzemeleri otomotiv sektöründe oldukça sık kullanılan seri imalat termo-plastiklerindendir. Birçok uygulamada yüzey enerjisi düşük olan bu malzemeler mekanik aşındırma veya alkol tabanlı temizleyiciler ile silinerek yapıştırma bağına hazırlanırlar. Bu çalışmada çevreye olumsuz etkisi olan hazırlık yöntemlerinin yerine, atmosferik basınçlı plazma (ABP) yönteminin kullanılabilirliği araştırılmıştır. Plazma uygulaması ile malzemelerin yüzey enerjilerinin yükseltilmesi uzun süredir bilinen bir yöntem olmakla birlikte vakum ortamında yapılan uygulamalar son yıllarda atmosfer basıncı altında da yapılabilir hale gelmiştir. Bu şekilde yöntemin etkinliği aynı kalırken uygulaması ve maliyeti iyileşmiştir. Boyama ve yapıştırma gibi uygulamalarda, araştırmalara katkı sağlamak için, ABP yöntemiyle gerçekleştirilen deneysel çalışmalar açıklanmış ve özellikle otomotiv sektöründe sık karşılaşılan POM ve PP malzemelerin yapıştırma uygulamalarında yöntemin alternatif olabileceği gösterilmiştir. ABP yönteminin çevreci bir süreç olduğu düşünüldüğünde günümüzde polimer malzemelerin yapıştırılması alanında da alternatif olacağı anlaşılmıştır.

(Invited) Atmospheric Pressure Plasma Treatment of Materials

Technologies based on the use of non-equilibrium plasmas have become virtually irreplaceable in diverse application fields. These range from modification/functionalization of surfaces of medical implants, production of functional thin films or nanostructured materials, light generation, environmental remediation, ozone generation or sterilization/decontamination of surfaces. However, there is a clear trend in the last few decades to substitute low-pressure plasma systems with the ones operated at atmospheric pressure. The interest in atmospheric pressure plasmas is stimulated not only by the decrease in equipment costs by avoiding expensive pumping systems of conventional low-pressure plasma devices but also by the possibility to process objects non-compatible with vacuum conditions. The latter triggered off rapid development of brand new scientific fields – plasma medicine and plasma agriculture.In this work, we briefly review the main operational principles of atmospheric pressure plasma sources, as well as the advantages/drawbacks of atmospheric plasma for a better understanding of the capabilities and limitations of the atmospheric plasma processing technology compared with conventional low-pressure plasma processing technologies. Subsequently, the possible use of two common atmospheric pressure plasma systems - dielectric barrier discharges and atmospheric pressure jets - will be demonstrated on the selected examples. The main emphasis will be given to the issues connected with the control of the wetting/drying/condensation of liquids on plasma-treated polymers, use of plasma pre-treatment on metallization of surfaces or their improved biocompatibility, application of atmospheric pressure plasma for deposition of nanostructured thin films, treatment of seeds with an aim to improve their germination, and last, but not least, the attention will also be devoted to the removal of organic deposits/contaminants, including pathogens, from different types of surfaces.

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.

Polarization spectroscopy for quantitative analysis of atmospheric CO2 and air plasma flows

This article demonstrates the feasibility of polarization spectroscopy as a diagnostic tool for quantitative analysis of atmospheric pressure plasma conditions. Atmospheric pressure air and CO2 plasma flows created in a microwave-powered plasma torch are investigated. A detailed line-by-line simulation approach is employed to interpret the polarization spectra recorded in the resonator of the plasma torch. The line-by-line code for the simulation of polarization spectroscopy of O2 Schumann–Runge has been developed and verified with measurements in atmospheric pressure O2 plasma for a previous study. In this study, this simulation code for O2 absorption is used to model the polarization spectra measured in CO2 plasma and determine the inner energy distribution of the molecules for the first time. The resulting vibrational and rotational temperatures are Tvib=6115K and Trot=2660K. In order to simulate measurements in air plasma, the line-by-line code is extended to enable two-species modeling using O2 Schumann–Runge as well as NOγ absorption. The new two-species simulation approach allows for the determination of the relative number density nO2/nNO=1500±100. This paper clearly demonstrates the value of polarization spectroscopy as a quantitative measurement technique for atmospheric pressure plasma applications.

Design and Medical Effects of a Vaginal Cleaning Device Generating Plasma-Activated Water with Antimicrobial Activity on Bacterial Vaginosis

Bacterial vaginosis is a common female disease caused by a vaginal infection due to an overgrowth of bacteria that naturally live in the vaginal tract. Bacterial vaginosis has frequently been treated with the oral or vaginal administration of antibiotics and topical disinfectants. However, hygienic application of topical treatment deep in the vagina remains difficult. Herein, we introduce a novel vaginal cleaning device using plasma-activated water generated from supplied water. Remarkably, plasma source generation at atmospheric pressure is well known to eradicate bacterial infection through the generation of free radicals and/or chlorine chemicals with antimicrobial activity. The device was designed to alleviate a bacterial infection by spraying plasma-activated water generated from a cleaning solution container with plasma modules. The spray nozzle contains both a clean outlet and a suction outlet to spray and recover the plasma water, respectively, and is connected to a disposable silicone tube. The other nozzle, which has a laser light and air pump, can perform a second sterilization and dry the vagina after washing. Free chlorine chemicals with antibacterial activity were detected in the plasma-activated water by the device. Clinical application in patients with bacterial vaginosis confirmed the stability and effectiveness of our device. Therefore, these results show a novel clinical application of atmospheric pressure plasma to medical field as a plasma medicine.

Reproducibility of ‘COST reference microplasma jets’

Atmospheric pressure plasmas have been ground-breaking for plasma science and technologies, due to their significant application potential in many fields, including medicinal, biological, and environmental applications. This is predominantly due to their efficient production and delivery of chemically reactive species under ambient conditions. One of the challenges in progressing the field is comparing plasma sources and results across the community and the literature. To address this a reference plasma source was established during the ‘biomedical applications of atmospheric pressure plasmas’ EU COST Action MP1101. It is crucial that reference sources are reproducible. Here, we present the reproducibility and variance across multiple sources through examining various characteristics, including: absolute atomic oxygen densities, absolute ozone densities, electrical characteristics, optical emission spectroscopy, temperature measurements, and bactericidal activity. The measurements demonstrate that the tested COST jets are mainly reproducible within the intrinsic uncertainty of each measurement technique.

The effect of non‐thermal atmospheric pressure plasma application on wound healing after gingivectomy

Recent studies have indicated the potential benefits of Non-thermal atmospheric pressure plasma (NTAPP) as a novel therapeutic approach. The purpose of the current study was thus to assess the effect of NTAPP on gingival wound healing. Fifteen patients with bilaterally symmetrical gingival hyperplasia were included in the study. After gingivectomy and gingivoplasty, the left-hand side of the symmetrical surgical area was irradiated with NTAPP (plasma jet kINPen 11). Digital photographs of the gingival wounds were taken at baseline and days 3, 7, and 14. Wound epithelialisation was evaluated. Landry Wound Healing Index (WHI) scores and visual analogue scale (VAS) scores were also recorded. There were significant differences between the epithelialisation of the NTAPP-treated sites and the control sites after the surgical procedures. The NTAPP-treated sites had significantly smaller stained surface areas compared with the control sites on the 3rd, 7th , and 14th days (P < .05). The NTAPP-treated sites had better WHI scores than the control sites throughout the follow-up period (P < .05). It can be concluded that NTAPP enhances epithelialisation and stimulates wound healing after gingivectomy and gingivoplasty. However, further clinical studies with larger sample sizes are needed to determine the exact benefits of NTAPP for gingival wound healing.

Application of atmospheric pressure plasma for adhesion improvement in polyurethane coating on polypropylene fabrics

Atmospheric pressure plasma treatment modifies the surface of textile materials at nano level. The effectiveness of plasma surface modification is closely associated with fabric weave construction and surface structure. Adhesion properties of three different polypropylene (PP) fabrics with a polyurethane (PU) coating have been investigated with respect to different plasma treatment time and power. Peel off strength was measured as the separation force required to separate coating layer from fabric. Statistical analysis of the peel off strength was performed by ANOVA. A substantial increase in adhesion of PU on plasma-treated samples was observed. Various characterization techniques such as contact angle, X-ray photoelectron spectroscopy, scanning electron microscopy and tensile measurement were used to inspect hydrophilicity, surface chemistry, surface morphology and physical properties of PP fabrics, respectively. As evident from results captured using various characterization techniques, atmospheric pressure plasma treatment enhances the surface properties (hydprophilicity, surface morophology and surface chemistry) without affecting the bulk (tensile strength) properties. It is shown that the plasma treatment parameters as well as the textile structure play an important role in adhesion improvement. Further, it is observed that the effectiveness of the plasma treatment is closely linked to the structure of the textiles fabrics.

Interaction of Plasma Jet With Methanol as Fundamental Processes in Solution

Plasma depollution is a relatively new field that investigates potential applications of atmospheric pressure plasma in environmental engineering, such as microorganism inactivation and degradation of organic molecules in water. In order to enunciate mechanisms of degradation of organic matter at molecular or atomic levels, the interaction between He, N2, O2, and air plasma jet and methanol in water was analyzed by gas chromatography–mass spectrum and Fourier transform infrared spectroscopy. Results show that the efficiency of methanol degradation is strongly dependent on the working gas and plasma treatment time. Compared to atmospheric pressure N2, O2, and air plasma jet, the He plasma jet may be utilized to degrade methanol more efficiently in aqueous solution. The efficiencies of degradation of methanol in water can be well described by using the chemical reaction rate model, where reactive oxygen and hydroxyl radical species play crucial roles in the degradation process. This paper provides an insight into the mechanism of degradation of organic pollutant in water by plasma.

Side effects by oral application of atmospheric pressure plasma on the mucosa in mice.

Cold atmospheric pressure plasma (CAP) has been investigated with promising results for peri-implant diseases treatment. However, prior to in-vivo applications of CAP sources in humans, short-term harmful mucosal damage or other unwanted side effects have to be reviewed. 180 male mice (B6C3F1) were divided into twelve treatment groups (n = 15). The right buccal cheek mucosa was treated with CAP. The first and second group each received continuous 10 sec irradiation with 2 different plasma sources (kINPen09, PS-MWM). The third group was treated with the kINPen09 for one minute. Control groups were treated with a corresponding dose of ultraviolet light for 8 seconds or 48 seconds and the other one was left untreated. The animals were weighed before and after treatment. The animals were sacrificed one day or one week after exposure. Stained tissue samples were histologically examined for tissue damage independently by two experienced pathologists. One day after CAP treatment histological analysis showed focal mucosal erosion with superficial ulceration and necrosis accompanied by a mild inflammatory reaction. One week after CAP treatment, the mucosal defects were completely re-epithelialized, associated with remnants of granulation tissue in the stroma irrespective of treatment duration. Furthermore, no cytological atypia was found and no severe weight loss occurred. The control groups did not show any alterations at all. CAP treatment led to a superficial mucosal damage that healed within few days. Nonetheless, further long-term experiments are necessary to exclude undesirable side effects after longer observation time. Particularly, potential carcinogenic effects must be ruled out prior to the application of CAP treatment in daily dental practice.

PR669: Application of atmospheric pressure plasma in the oral cavity: long‐term‐experiments for risk assessment in mice

PR669: Application of atmospheric pressure plasma in the oral cavity: long‐term‐experiments for risk assessment in mice

Design optimization of an air atmospheric pressure plasma‐jet device intended for medical use

The current and potential applications of atmospheric pressure plasmas in medicine generate an increasing need to develop safe and reliable plasma devices for patient treatment. This paper shows how the estimation of safety risks, the stability of the generated plasma, and the effectiveness in the aimed application can orientate the design process of a specific atmospheric pressure plasma device intended for clinical use. A promising plasma jet device operated with air is optimized, leading to a configuration with a more advanced design that reduces the temperature of the effluent, prevents the material degradation and improves the isolation of the high voltage components. The effects of the plasma jet treatment are investigated by chemical analysis of demineralized water and inactivation tests on E. coli cultures.

Atmospheric pressure plasma treatment of agricultural seeds of cucumber (Cucumis sativus L.) and pepper (Capsicum annuum L.) with effect on reduction of diseases and germination improvement

The paper presents the effects of plasma treatment on agricultural seeds. Cucumber and pepper seeds, widely used in agriculture, were treated using the Diffuse Coplanar Surface Barrier Discharge (DCSBD) at atmospheric pressure in ambient air. The plasma treatment (4 s for pepper, 20 s for cucumber) led to an improvement of germination and germinating power. XPS confirmed chemical changes on the seed surface. The surface morphology of the plasma treated seeds showed no evidence of structural damage. The conclusion is that DCSBD proves to be able to reduce some of the microorganisms and pathogens affecting the seeds. Thanks to their technical simplicity and easy scaling‐up, DCSBD plasma sources open new opportunities for atmospheric pressure plasma application in the agricultural industry.

Color development, physiochemical properties, and microbiological safety of pork jerky processed with atmospheric pressure plasma

Abstract We investigated the applicability of atmospheric pressure plasma (APP) as an alternative to sodium nitrite in pork jerky manufacturing. Pork slices were marinated in brine with no sodium nitrite at 4 °C for 16 h and treated by APP for 0, 20, 40, and 60 min, respectively. The sample marinated in the brine with sodium nitrite (100 ppm) was also prepared. Then, all samples were dried. As APP treatment time increased, the a⁎ value (redness), nitrosoheme pigment content, and residual nitrite content increased, while lipid oxidation decreased (all P Industrial relevance The global interest in sodium nitrite substitute for meat products manufacturing has considerably grown for years because consumer's demand of foods labeled “natural” and “chemical-free” has been increasing. In general, APP is recognized as a novel non-thermal food processing technology that uses energetic, reactive species to inactivate microbes on various foods. Recently, meat curing system involving direct APP treatment was proposed. The present study tried to apply APP to manufacturing pork jerky without using sodium nitrite. As a result, similar quality properties, particularly color, were observed in jerky applied by APP compared to jerky made with sodium nitrite. Application of APP also improved the microbiological safety of pork jerky. Therefore, APP can be applied for manufacturing potentially safer pork jerky by inactivation of heat-resistant pathogens without added sodium nitrite.

Thin insulating film deposition on copper by atmospheric‐pressure plasmas

Long‐time partial discharge (PD) is regarded as one of the main reasons for the insulation failure of high‐voltage cables. In this work, we report on the application of atmospheric pressure plasma to deposit siloxane film on copper to avoid PDs. The dielectric barrier discharge (DBD) plasma is driven by AC power supply, with tetraethoxysilane (TEOS), argon, and oxygen mixture as the source gas. The effect of oxygen gas flow rate on the thin film surface morphology, chemical composition, and electrical properties is studied systematically. Our results show that the stability of the plasma deteriorated, when the oxygen flow rate exceeded 10 sccm. The addition of oxygen in the source gas induced a high oxidation level of deposited thin film. The chemical composition of thin film was in the form of SiOx (x = 1.9) with 10 sccm oxygen compared to SiOx (x = 1.2), when deposited in the absence of oxygen. Additionally, the optimal thin film with good stability was obtained with the surface resistivity 1.1 × 1011 Ω, when deposited in the absence of oxygen. The corresponding relative permittivity of the deposited thin film is 2.9. The simulation results demonstrated that the electric field distortion was weaken after the film deposition, which reduced the probability of PD to occur.

Influence of gas flow velocity on the transport of chemical species in an atmospheric pressure air plasma discharge

This paper reports on a numerical study of the transport of reactive chemical species generated in an atmospheric-pressure air plasma discharge under the influence of a high velocity flowing gas. Using a 1D air plasma model, it is shown that the reactive species transported downstream of the discharge region can be categorized into three distinct groups based on their spatial distribution: (i) decaying downstream species, (ii) increasing downstream species and (iii) variable density species, where the density is a function of both spatial position and gas flow velocity. It is demonstrated that the gas flow velocity influences the dominant chemical reactions downstream of the discharge region, noticeably altering the composition of several key reactive chemical species transported to a given downstream location. As many emerging applications of atmospheric pressure plasma are driven by the flux of reactive chemical species, this study highlights the importance of gas flow velocity, not only as a means to enhance mass transport but also as a means to manipulate the very nature of the reactive plasma chemistry arriving at a given location.

表面処理のための大気圧直線型マイクロ波プラズマ

Atmospheric pressure plasma is a powerful tool for various material processing. In this article, development of atmospheric pressure plasmas are reviewed, particularly for glow-like plasma which is characterized by spreading in space and has an advantage applicable to surface treatment. One important issue in application of atmospheric pressure plasma is a large area processing, and as one candidate for the purpose, line-shaped microwave plasma in atmospheric pressure is also reviewed.

Concepts and characteristics of the ‘COST Reference Microplasma Jet’

Biomedical applications of non-equilibrium atmospheric pressure plasmas have attracted intense interest in the past few years. Many plasma sources of diverse design have been proposed for these applications, but the relationship between source characteristics and application performance is not well-understood, and indeed many sources are poorly characterized. This circumstance is an impediment to progress in application development. A reference source with well-understood and highly reproducible characteristics may be an important tool in this context. Researchers around the world should be able to compare the characteristics of their own sources and also their results with this device. In this paper, we describe such a reference source, developed from the simple and robust micro-scaled atmospheric pressure plasma jet (μ-APPJ) concept. This development occurred under the auspices of COST Action MP1101 ‘Biomedical Applications of Atmospheric Pressure Plasmas’. Gas contamination and power measurement are shown to be major causes of irreproducible results in earlier source designs. These problems are resolved in the reference source by refinement of the mechanical and electrical design and by specifying an operating protocol. These measures are shown to be absolutely necessary for reproducible operation. They include the integration of current and voltage probes into the jet. The usual combination of matching unit and power supply is replaced by an integrated LC power coupling circuit and a 5 W single frequency generator. The design specification and operating protocol for the reference source are being made freely available.