Argon Gas Plasma Research Articles

Effects of Argon Gas Plasma Treatment on Biocompatibility of Nanostructured Titanium.

In this study, we applied argon plasma treatment to titanium surfaces with nanostructures deposited by concentrated alkali treatment and investigated the effects on the surface of the material and the tissue surrounding an implant site. The results showed that the treatment with argon plasma removed carbon contaminants and increased the surface energy of the material while the nanoscale network structure deposited on the titanium surface remained in place. Reactive oxygen species reduced the oxidative stress of bone marrow cells on the treated titanium surface, creating a favorable environment for cell proliferation. Good results were observed in vitro evaluations using rat bone marrow cells. The group treated with argon plasma exhibited the highest apatite formation in experiments using simulated body fluids. The results of in vivo evaluation using rat femurs revealed that the treatment improved the amount of new bone formation around an implant. Thus, the results demonstrate that argon plasma treatment enhances the ability of nanostructured titanium surfaces to induce hard tissue differentiation and supports new bone formation around an implant site.

Investigating the effect of atmospheric plasma on protein fibrinogen: Spectroscopic and biophysical analysis

AbstractCold atmospheric plasma (CAP) has gained significance in recent years and different prospects of it have been studied widely owing to its effectiveness and eco‐friendly nature. CAP has been used extensively in wound healing. However, a detailed understanding of the interaction of the CAP with different protein macromolecules present in our body is essential. In this study, we emphasize how CAP affects the protein fibrinogen. Fibrinogen is a major protein involved in blood clotting and the major protein in the blood. Numerous spectroscopic investigations have been done including UV spectroscopy, fluorescence spectroscopy, dynamic light scattering (DLS), and Zeta. This work shines a light on protein self‐assembly to bring the future possibilities of bio‐medicine with CAP treatment. Fibrinogen undergoes structural changes around tryptophan residue as evidenced by UV spectroscopy and quenching in fluorescence spectroscopy. The order of the fluorescence quenching is Oxygen > Helium > Argon gas plasma. 2,4‐dinitrophenylhydrazine (DNPH) assay supports fluorescence studies as more protein carbonyls are formed in the case of argon and oxygen gas plasma. DLS and Zeta potential measurements prove that the protein Fibrinogen undergoes a self‐assembly process to form organized assemblies in the presence of a plasma jet. Reactive oxygen and reactive nitrogen species produced in the plasma have been evaluated using various assays and correlated with the other studies. This study will help understand protein fibrinogen's self‐assembly process and pave the way for the CAP application in wound healing.

Enhancement of S-scheme heterojunction hematite and titanium dioxide nanocomposite by plasma treatment in the photocatalytic membrane for hydrogen separation

This work evaluated the performance of the photocatalytic membrane reactor (PMR) for hydrogen and oxygen separation. The PMR was conducted in a 500-ml reactor under solar light simulated by a mercury arc lamp (250 W). Hematite (α-Fe2O3) was deposited on titanium dioxide (TiO2) by sol-gel method on the Ti foil while palladium (Pd) was deposited on the other side. The sample surface was modified by argon (Ar) gas plasma treatment at 50 W for 10 min. The S-scheme heterojunction photocatalyst was characterized by X-ray diffraction, scanning electron microscope, transmission electron microscopy, and UV–vis spectroscopy. The charge carrier transport of photocatalysts was also analyzed. The photocatalytic activity was significantly improved by plasma treatment. The band gap energy decreased from 1.88 eV to 1.77 eV, and the average crystalline was reduced from 21.62 ± 4.79 nm to 21.34 ± 5.63 nm. The photocatalytic activity of fabricated materials for hydrogen production was evaluated in multi-cycle experiments. The highest hydrogen production rate of 1346.19 µmol h−1 was observed for the Ar plasma-treated heterojunction α-Fe2O3 and TiO2 nanocomposite sample (α-Fe2O3 @TiO2-P). After 5 cycles, the photocatalyst reaction of α-Fe2O3 @TiO2-P under solar light irradiation showed high stability for H2 production of 85.24 % compared to the first cycle. The S-scheme was photogenerated of charge transferred of type S-scheme mechanism between α-Fe2O3 and TiO2 under solar light. This work provides insight to enhance hydrogen production through the modification of the S-scheme photocatalyst membrane. The improved photocatalytic performance of the fabricated material suggests the effectiveness of the proposed Ar plasma treatment strategy to enhance the photoactivity for H2 production via water splitting.

Influence of power-dependent Argon gas plasma treatment on the electron field emission properties of carbon nanotube field-emitters

Influence of power-dependent Argon gas plasma treatment on the electron field emission properties of carbon nanotube field-emitters

Argon Humidification Exacerbates Antimicrobial and Anti-MRSA kINPen Plasma Activity.

Gas plasma is a medical technology with antimicrobial properties. Its main mode of action is oxidative damage via reactive species production. The clinical efficacy of gas plasma-reduced bacterial burden has been shown to be hampered in some cases. Since the reactive species profile produced by gas plasma jets, such as the kINPen used in this study, are thought to determine antimicrobial efficacy, we screened an array of feed gas settings in different types of bacteria. Antimicrobial analysis was performed by single-cell analysis using flow cytometry. We identified humidified feed gas to mediate significantly greater toxicity compared to dry argon and many other gas plasma conditions. The results were confirmed by inhibition zone analysis on gas-plasma-treated microbial lawns grown on agar plates. Our results may have vital implications for clinical wound management and potentially enhance antimicrobial efficacy of medical gas plasma therapy in patient treatment.

Effect of Microstructural and Tribological Behaviors of Sputtered Titanium Carbide Thin Film on Copper Substrate

Titanium carbide (TiC) thin films were deposited by radio frequency magnetron sputtering (RFMS) onto a copper substrate by using Argon (Ar) gas plasma at a gas flow rate of 10.0 sccm. The effect of time and temperature at a constant RF power on the structural and tribological properties were respectively investigated by atomic force spectroscopy (AFM), X-ray Diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, optical microscopy (OM), scanning electron microscopy (SEM) and tribological measurements. All films were tested to have crystal structures with the preferential plane (111) and dominant plane (200) grain orientations. Thus, plane (111) has phase identification of Cu(Cu16Ti)0.23 for some samples, whereas plane (200) has a phase identification of Cu(Cu0.997Ti0.003) and Cu(Cu0.923Ti0.077) for other samples. The lowest thin film roughness of 19.797 nm was observed in the sample, with RF power, sputtering time, and a temperature of 200 W, for two hours and 80 °C, respectively. The FTIR spectra of TiC films formed under different sputtering times (2-3 h) and temperatures (80 °C-100 °C) on Cu substrates at a constant sputtering power of 200 W in the range of 5000-500 cm-1. The peaks at 540 cm-1, 780 cm-1, and 1250 cm-1 are presented in the FTIR spectra and the formation of a Ti-C bond was observed. On the other hand, a sample was revealed to have the lowest wear volume of 5.1 × 10-3 mm3 while another sample was obtained with the highest wear volume of 9.3 × 10-3 mm3.

The Study of the Characteristics of a Microwave Plasma Jet Operated with Ar at Atmospheric pressure

In recent years, non-thermal atmospheric pressure plasma has attracted wide interest in industrial and biomedical fields due to its many advantages, such as its high efficiency, simple systems, easy operation, non-toxic residue, and low cost. In this project, non-thermal (cold) plasma generated using a voltage source with a precise frequency (microwave up to 2.4GHz) using argon gas. The electrical properties studied to describe the discharges of argon gas plasma jets at different flow rates (Flow= (1, 2, 3, 4) L/min) and with voltages (150 V). The produced plasma jet column will be analyzed using Optical Emission Spectrometry (OES) technology to determine plasma parameters such as electron temperature (Te), electron density (ne), plasma frequency (fp), Debye length (λD), and Debye (ND) number of the argon plasma jet. We use the Boltzmann plot to determine the electron temperature (Te) in the plasma, and the electron density (ne) is calculated by Stark broadening. The value of the electron temperature decreases from (0.991-1.273) eV and the electron density rises from (2.173-3.664) x1017 cm-3 with higher gas flow rates, also the Plasma plume length rises from (1.1-3.5) cm with higher gas flow rates, while the plasma jet temperature decreased with higher gas flow rates.

Development of Plasma Parameters for the Manufacture of MCrAlY Bond Coats by Low‐Pressure Plasma Spraying Using a Cascaded Torch

MCrAlY bond coats (MNi, Co) for thermal barrier coating systems are often manufactured by low‐pressure plasma spraying (LPPS) to achieve dense coatings with low oxygen uptake at high deposition efficiencies. Herein, the novel SinplexPro 03C plasma spray torch (Oerlikon Metco) is characterized regarding this application, and appropriate process parameters are developed. The mass‐specific plasma enthalpy and the hydrogen–argon plasma gas ratio prove to be substantial factors. The best deposition efficiency and lowest porosity are achieved at a mass‐specific plasma enthalpy between 17 and 19 MJ kg−1. The oxygen content increases degressively with the enthalpy. Already at small hydrogen fractions in the plasma gas, a fast route is established for the recombination of argon ions. Consequently, the thermal treatment of the feedstock is improved. Moreover, the porosity decreases at increasing hydrogen content of the plasma gas, as the gun is operated in constant current mode and thus the input power increases. However, the deposition efficiency decreases slightly. On the other hand, the oxygen content decreases due to the reducing effect of hydrogen. The deposition efficiency, porosity, and oxygen content are also reasonable if no hydrogen is admixed at all, as the fluctuations of the plasma are reduced.

Plasma nano-patterning for altering hydrophobicity of copper substrate for moist air condensation

Fabrication of durable hydrophobic metallic substrate is an emerging area of research for the condensation process in many industrial devices because its implementation enhances the efficacy of the devices. In this work, effective and durable hydrophobic copper (Cu) substrates were fabricated by plasma nano-pattering. Various discharge voltages were used to create various types of nano-patterns textured on copper substrates. For 30 min of irradiation of Argon gas plasma at various discharge voltages of 500, 650 and 750 V, morphologies of substrates were altered such that micro-litre water droplet has contact angle of 105 ± 3o, 97 ± 5o, and 95 ± 5o, respectively. However, pristine polished Cu substrate has water droplet contact angle of 56±5o. The micro-graph of scanning electron microscope (SEM) showed micro-order to nano-order roughness on etched substrates and the structure of nano-patterns was different for different discharge voltages for given period of argon ions irradiation. The etched copper substrate at 500 V was deployed as a condensing surface for moist air condensation of temperature 28 °C, relative humidity 70% and degree of sub-cooling 10°C. These results showed that the water condensation rate of plasma etching hydrophobic Cu substrate was 438 ml/m2-h, compared to 188 ml/m2-h for pristine Cu substrate.

Effects of gas type and cold plasma treatment time on Lecanicillium fungicola spores reduction and changes in qualitative, chemical, and physiological characteristics of button mushroom during postharvest storage

This study aimed to inhibit the growth of Lacanicillium fungicola and improve the quality of button mushroom during a 21-day storage time at 4°C using the treatment of surface dielectric barrier discharge plasma. Three gases of argon (Ar), surface evaporation of hydrogen peroxide (H2O2vapor) by argon and H2O2vapor by air were used as the injecting gas within processing times of 30, 60, 120, and 180 s. The results showed that 180 s treatment with H2O2vapor+Air plasma decreased L. fungicola spores about 3-log compared with untreated samples after 21 days of storage. In addition, physicochemical and physiological properties of button mushroom were investigated during the storage period. Polyphenol oxidase and peroxidase enzymes residual activity of samples treated by 180 s of H2O2vapor+Ar plasma reduced 93.95% and 94.1% immediately after treatment, respectively. Furthermore, stiffness, color, phenolic and antioxidant compounds on the 21st day of storage improved compared with untreated samples. Novelty impact statement The mixture of hydrogen peroxide vapor with air as injecting gas plasma was able to inactivate Lacanicillium fungicola spores on the surface of button mushrooms. 180 s treatment with hydrogen peroxide vapor with argon gas plasma improved the color, firmness, phenolic and antioxidant content than control. The treatment by surface dielectric barrier plasma increased the shelf life of button mushroom by reducing the activity of lipid oxidation and PPO, POD enzymes residual activity.

Enhancement of Electrical Properties of Sol-Gel Indium-Tin-Oxide Films by Microwave Irradiation and Plasma Treatment.

We proposed the enhancement of the electrical properties of solution-processed indium–tin–oxide (ITO) thin films through microwave irradiation (MWI) and argon (Ar) gas plasma treatment. A cost- and time-effective heat treatment through MWI was applied as a post-deposition annealing (PDA) process to spin-coated ITO thin films. Subsequently, the sheet resistance of MWI ITO thin films was evaluated before and after plasma treatment. The change in the sheet resistance demonstrated that MWI PDA and Ar plasma treatment significantly improved the electrical properties of the ITO thin films. Furthermore, X-ray photoelectron spectroscopy and X-ray diffraction analyses showed that the electrical properties of the ITO thin films were enhanced by the increase in oxygen vacancies due to the ion bombardment effect of high-energy plasma ions during Ar plasma treatment. Changes in the band gap structure of the ITO thin film due to the ion bombardment effect were also analyzed. The combination of MWI PDA and Ar plasma treatment presents new possibilities for improving the high-conductivity sol–gel ITO electrode.

Modification of surface α-Fe2O3/TiO2 photocatalyst nanocomposite with enhanced photocatalytic activity by Ar gas plasma treatment for hydrogen evolution

In this work, hematite (α-Fe2O3) deposited on anatase TiO2 was modified by plasma treatment and studied. α-Fe2O3/TiO2 was successfully synthesized using sol-gel precipitation methods and the surface was modified by argon (Ar) gas plasma treatment to increase photocatalyst nanocomposite activity. The effect of Ar-plasma treatment times from 5 to 20 min at DC glow discharge powers of 50 watts was investigated. The crystal structures, surface morphology, optical properties were characterization by using X-ray Diffractometry (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), UV–vis spectrometry (UV–Vis), X-ray photoelectron spectroscopy (XPS), photoluminescence spectroscopy (PL) and electrochemical impedance spectroscopy (EIS). After plasma treatment, the crystalline phase of TiO2 form changed from pure anatase to a mixture of anatase and rutile phases. The particle size was reduced from 25 to 20 nm. The band gap energy decreased from approximately 2.18 eV to 1.84 eV and exhibited a wider absorption edge under visible light irradiation (400–700 nm). Ar-plasma modification of the surface showed the attribution of oxygen vacancies and Ti3+. The plasma treatment improved the heterojunction photocatalyst to enhance the photocatalytic activity under visible light for H2 evolution. The best photocatalytic activity for H2 evolution rate was obtained at 1.25 mmol h-1 for α-Fe2O3/TiO2-10 photocatalyst compared to α-Fe2O3/TiO2-untreated (0.13 mmol h-1). The plasma treatment on photocatalyst materials showed long-term stability and excellent separation of the photogenerated charge carriers.

Manufacturing of Cold Plasma System and Studies Electrical Characteristic

In this research, the non-thermal plasma system is designed with diameter (10 mm) Argon at atmospheric pressure as well as to be suitable for use in medical and biotechnological applications. The electric description of this system was studied. In this paper, a non-pure argon gas plasma system is designed and manufactured that operates at pressure The normal air. Where the electrical description of this system was studied through the use of values Different voltages and different values of how quickly the argon flows. As the results obtained showed the small value of the electric current consumed by the needle system Non-thermal plasma, where it was in the range of several microns of amps, and the value of the electric current increased with the increase in the gas flow, and the results also showed a breakdown of voltages when the voltage used was 5 kilovolts, which caused a slight decrease in the value of the electric current when the gas flow was 4 liters The minute.

Interfacial performance enhancement of carbon fiber/epoxy composites by a two-step surface treatment

Carbon fiber-reinforced polymer composites (CFRPs) have many features, such as lightweight, high specific strength, and excellent chemical resistance. However, the adhesion at the interface of the CFRPs, which are composed of fiber and resin, is poor. Thus, de-lamination and interfacial peeling occur, and the mechanical properties, such as intrinsic strength and rigidity, decrease. Fiber surface modification by plasma and silane coupling treatments has attracted much attention to improve these properties. In this study, argon and oxygen mixed gas plasma treatment was used as pretreatment to introduce hydroxyl group on the fiber surface. This method was utilized to improve the adhesion between the fiber and resin. A silane coupling treatment was conducted to bond the carbon fiber and epoxy resin by chemical covalent bonding. The effect of silane coupling treatment on the interfacial property of CFRPs was investigated. Elemental analysis of the surface modified carbon fiber was explored through energy dispersive X-ray spectrometry. The functional groups of different carbon fiber surfaces were analyzed through X-ray photoelectron spectroscopy. The wettability of the treated carbon fiber was examined with a contact angle meter. The interlaminar shear strength was determined with a short beam method.

Comprehensive assessment of hydrogen production in argon‐water vapors plasmolysis

AbstractA simultaneous investigation of simulation and experimental analysis of hydrogen production from argon‐water vapor mixture as a function in DBD plasma applied voltage were studied. The H2 concentration results of two Ar‐H2O simulation kinetics models were compared with the experimental results. The simulation analysis was implemented for Ar‐H2O models with and without the dissociative attachment reaction (H−). The effects of argon flow rate, input water vapor temperature, and water vapor flow rate on the H2 concentration from the Ar‐H2O mixture were investigated. Furthermore, the effect of argon addition and reactor temperature on the hydrogen production from water vapor plasmolysis was performed. It was found that the hydrogen concentration was enhanced with the argon gas flow rate and plasma voltage increase. Moreover, the H2 concentration results of the water vapor simulation model selecting the dissociative attachment reaction (H−) were nearly the same as that obtained from the experimental results. Also, it was observed that the energy efficiency was enhanced with the plasma input power increased. Moreover, the comparison showed that the hydrogen concentration of argon gas addition was lower than that obtained from water vapor plasmolysis at PTR heating temperature of 90°C.

Effect of DC micro-plasma treatment on bacteria in its vegetative bacteria

Argon gas plasma consists of discharge pattern of micro hollow cathode. The pattern is used to inactivate the two main kinds of bacteria. The Culture of Escherichia Coli (gram positive) and Staphylococcus aureus (gram negative) are subjected to the plasma exposure. The micro-plasma jet (MPJ) discharge was generated in the voltage range of 2-10 kV with an operating current of 20-35 mA. Under such conditions, a MPJ of approximately 1 cm visible length was produced. The power efficiency of this device was approximately 80%. The efficacy of MPJ to inactivate the bacteria is determined by observing colony forming unit (CFU) counts before and after plasma exposure. The Colony counter is used here to find the CFU/plate. The effect of plasma exposure is observed by varying the time at 15, 30, 60, 90, 120, 150 and 180 seconds. An efficient reduction in CFU is observed after plasma exposure, particularly for 120 seconds. Approximate 50% decay of both cultures is observed after treatment time of 120 seconds.

Chipboards with Plasma Protective Decorative Coatings

A plasma technology has been developed for the production of chipboard with vitreous protective decorative coatings. To prevent high temperatures of the plasma jet from being applied to the front surface of the chipboard, an intermediate layer was applied, which included a mixture of sodium liquid glass with colored glass powders based on profiled and sheet cullet. The technology of a two-stage deposition of an intermediate layer before plasma spraying of the main vitreous coating has been developed. The technology provides for the preliminary front surface preparation and the liquid glass application on a wood chipboard, the intermediate layer application and subsequent drying at 95 °C. The adhesion strength of the intermediate layer with the matrix was 1.6–1.8 MPa. The optimal technological parameters of plasma-chemical modification of a protective decorative coating based on fine powders of sheet and profiled glasses have been established: the power of an electric arc plasma installation operation is 8 kW, the flow rate of argon plasma gas - 2.0 m3/hour. It is shown that the water resistance of protective decorative coatings based on profiled and sheet glass is III hydrolytic class. Vitreous coatings had high reliability and durability, in particular, acid resistance, alkali resistance and microhardness. Due to the electric arc plasma installations use for plasma-chemical modification of protective decorative coatings based on profiled and sheet glass cullet, the technology is resource and energy efficient, and is also recommended for introduction both in furniture industry and in the construction industry.

Pattern Formation in High Power Impulse Magnetron Sputtering (HiPIMS) Plasmas

High power impulse magnetron sputtering (HiPIMS) plasmas produce a very energetic growth flux for the synthesis of thin films with superior properties. High power densities in the range of a few $$\hbox {kW}/\hbox {cm}^2$$ are applied to a metal target electrode in short pulses with a length of 10–$$400\,\upmu \hbox {s}$$ and duty cycles of a few percent or less in an argon plasma gas. Fast camera and probe measurements revealed the formation of very characteristic plasma patterns that become visible as rotating localized ionization zones, so called spokes. The appearance of these spokes at high plasma powers is believed to be essential for the good performance of HiPIMS plasmas. The rotation direction of the spokes is in $$\vec {E} \times \vec {B}$$ direction at high plasma powers, but in retrograde $$\vec {E} \times \vec {B}$$ direction at low plasma powers. This characteristic behavior is explained by applying a simple drift wave model from literature and comparing the dispersion relation of those waves with measured data. The pronounced rotation reversal is explained by either a change in the governing density gradient in the plasma or by the change in the direction of the streaming ions during the transition from an argon dominated regime at low powers to a metal dominated regime at high powers.

Boost inverter for Atmospheric Argon Plasma

The paper describes a high power boost inverter for atmospheric Argon plasma (Ar). A high frequency was used in order to drive the pulse width modulation circuit. The average output current consumption (AOCC) was modified from (20A) up to (30A) by increasing the duty ratio from (0.77) up to (0.88) for the atmospheric Argon gas plasma. The switching frequency of the boost inverter was fixed at (20KHz).

Silver nanoparticle-loaded filter paper: Innovative assembly method by nonthermal plasma and facile application for the reduction of methylene blue

In this study, silver nanoparticles (AgNPs) were loaded onto commercial filter paper using a simple “suspending-discharging-washing” process. Nanosecond pulse dielectric barrier discharge (NP-DBD) plasma was used to perform the in-situ reduction-loading process in a plate-to-plate DBD reactor during the five-minute fabrication process. Gaseous ethanol was used as the reducing agent under an argon gas plasma treatment. There was no thermal treatment, which prefers the formation of small nanoparticles. Transmission electron microscopy showed that the synthesized AgNPs were well-dispersed over the surface of the filter paper. The synthesized nanoparticles were hemispherical and crystalline. Fourier transform infrared spectroscopy showed that the cellulose skeletons had been mostly maintained after the plasma discharge. The catalytic activity of the AgNPs paper was evaluated by the reduction reaction of methylene blue (MB) with sodium borohydride (NaBH4) using a straightforward filtration process.