Atmospheric Pressure Plasma Research Papers (original) (raw)

High performance polymer, Polyether Ether Ketone (PEEK) (service temperature −250°C to +300°C, tensile strength: 120 MPa) is gaining significant interest in aerospace and automotive industries. In this investigation, attention is given to... more

High performance polymer, Polyether Ether Ketone (PEEK) (service temperature −250°C to +300°C, tensile strength: 120 MPa) is gaining significant interest in aerospace and automotive industries. In this investigation, attention is given to understand adhesion properties of PEEK, when surface of the PEEK is modified by two different plasma processes (i) atmospheric pressure plasma and (ii) low pressure plasma under DC Glow Discharge. The PEEK sheets are fabricated by ultra high temperature resistant epoxy adhesive (DURALCO 4703, service temperature −260°C to +350°C). The surface of the PEEK is modified through atmospheric pressure plasma with 30 and 60 s of exposure and low pressure plasma with 30, 60, 120, 240, and 480 s of exposure. It is observed that polar component of surface energy leading to total surface energy of the polymer increases significantly when exposed to atmospheric pressure plasma. In the case of low pressure plasma, polar component of surface energy leading to total surface energy of the polymer increases with time of exposure up to 120 s and thereafter, it deteriorates with increasing time of exposure. The fractured surface of the adhesively bonded PEEK is examined under SEM. It is observed that unmodified PEEK fails essentially from the adhesive to PEEK interface resulting in low adhesive bond strength. In the case of surface modified PEEK under atmospheric pressure plasma, the failure is entirely from the PEEK and essentially tensile failure at the end of the overlap resulting in significant increase in adhesive bond strength. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

A cold atmospheric pressure plasma source, called hairline plasma, for biological and medical applications has been developed. Using the physical effect of the negative dc corona discharge, a nanosecond pulsed microplasma has been... more

A cold atmospheric pressure plasma source, called hairline plasma, for biological and medical applications has been developed. Using the physical effect of the negative dc corona discharge, a nanosecond pulsed microplasma has been created. The device produces a very thin (d~30 mum) plasma filament with a length of up to 1.5 cm. Due to this geometrical parameters this plasma is

Analysis of Electric Circuit Model on Atmospheric Pressure Dielectric Barrier Discharge (DBD) Plasma has been simulated using the Simulink-Matlab R2010a software. Plasma reactor being used as the basis to determine the parameters in the... more

Analysis of Electric Circuit Model on Atmospheric Pressure Dielectric Barrier Discharge (DBD) Plasma has been simulated using the Simulink-Matlab R2010a software. Plasma reactor being used as the basis to determine the parameters in the circuit is in the coaxial form made of pyrex glass with an iron rod as the active electrode and spiral copper wire as passive electrode. The reactor was filled with argon gas with the flow rate of 2 L/s. Simulation circuit model which was prepared based on a DBD equivalent circuit, operated in a voltage range of 1.0 kV to 6.0 kV for frequency of 10 kHz to 66 kHz. Electrical characterization was performed to describe the plasma discharge that occurs in the reactor. The datas of supply voltage and current, as well as voltage and current discharge, was used to determine the average power during one period. From the simulation was obtained an increase in supply and discharge currents with increasing of frequency at the same operating voltage. Discharge power has increased in a specific voltage and increased frequency. It is obtained the average discharge power for 5.5 kV of 11.28 W and 10.90 W at a frequency of 21 kHz and 24 kHz, respectively. The highest efficiency obtained from the simulation that achieved at voltage of 1 kV and frequency of 45.7 kHz is equal to 56.59%.

There are many current and emerging adhesion issues which require an additional process to enhance interfacial surface properties. Materials which are non-polar, such as polymers, have low surface energy and therefore typically require... more

There are many current and emerging adhesion issues which require an additional process to enhance interfacial surface properties. Materials which are non-polar, such as polymers, have low surface energy and therefore typically require surface treatment to promote adhesion. One way of increasing surface energy and reactivity is to bombard a polymer surface with ions. This is achieved by the surface treatment with plasma. Basically, a plasma treater ionizes a gas mixture in an electromagnetic field. The ionized gas is then discharged on the polymer surface, increasing the presence of chemical functional groups on it. Among surface treatments, corona discharge is the most common method. Typically used for thin webs, corona treaters utilize air as working gas. For treating complex surfaces, atmospheric plasma glow discharge treatment is often the best approach. This plasma offers stable, more uniform and longer-lasting surface energy enhancement than corona discharge. In particular, plasma provides a critical advantage when processing steps are required for enhancing the properties of very low energy and reactivity surfaces, such as non-polar polyolefins. Many materials, in fact, require surface treatments to adhere to inks and coatings. Promoting adhesion is made even more challenging with the use of water-based coatings, which have higher surface tension than solvent coatings and thus even less tendency to wet-out on a polymer surface. The aim of our book is a discussion about the use of corona discharge and emerging atmospheric plasma treatments in several applications within converter and textile industries.
Amelia Sparavigna, Rory A. Wolf

There are many current and emerging wetting and adhesion issues which require an additional surface processing to enhance interfacial surface properties. Materials which are non-polar, such as polymers, have low surface energy and... more

There are many current and emerging wetting and adhesion issues which require an additional surface processing to enhance interfacial surface properties. Materials which are non-polar, such as polymers, have low surface energy and therefore typically require surface treatment to promote wetting of inks and coating. One way of increasing surface energy and reactivity is to bombard a polymer surface with atmospheric plasma. When the ionized gas is discharged on the polymer, effects of ablation, crosslinking and activation are produced on its surface. In this paper we will analyse the role of plasma and its use in increasing the surface energy to achieve wettability and improve adhesion of polymeric surfaces.

The development of a three-electrode trigatron gap with the trigger electrode inside the main electrode is discussed in this paper. Two models of the operation mechanism are proposed to explain the breakdown in the trigatron gap. In... more

The development of a three-electrode trigatron gap with the trigger electrode inside the main electrode is discussed in this paper. Two models of the operation mechanism are proposed to explain the breakdown in the trigatron gap. In addition, a mathematical model was proposed to calculate the breakdown time based on the theoretical analysis. The influence of different parameters on the breakdown time is discussed. Some characteristics in dry air have been experimentally determined such as the influence of the air pressure and the influence of the undervoltage ratio on the spark gap operation. The experimental results show that the operating voltage range between 0.5 and 0.7 might be reasonable. Then, the experimental results and analysis demonstrate that there are three regions divided by two inflection points, and the corresponding values of the undervoltage ratio are threshold values presenting different breakdown processes.

As demonstrated by Parent, B., et al., (“Electron and Ion Transport Equations in Computational Weakly-Ionized Plasmadynamics,” Journal of Computational Physics, Vol. 259, 2014, pp. 51–69), the computational efficiency of the... more

As demonstrated by Parent, B., et al., (“Electron and Ion Transport Equations in Computational Weakly-Ionized Plasmadynamics,” Journal of Computational Physics, Vol. 259, 2014, pp. 51–69), the computational efficiency of the drift-diffusion plasma model can be increased significantly by recasting the equations such that the potential is obtained from Ohm’s law rather than Gauss’s law and by adding source terms to the ion transport equations to ensure that Gauss’s law is satisfied. Not only did doing so reduce the stiffness of the system, leading to faster convergence, but it also resulted in a higher resolution of the converged solution. The combined gains in convergence acceleration and resolution amounted to a hundredfold increase in computational efficiency when simulating nonneutral plasmas with significant quasi-neutral regions. In this paper, it is shown that such a recast of the drift-diffusion model has yet another advantage: its lack of stiffness permits the electron and ion transport equations to be integrated in coupled form along with the Favre-averaged Navier–Stokes equations. Test cases relevant to plasma aerodynamics (including nonneutral sheaths, magnetic field effects, and negative ions) demonstrate that the proposed coupled system of equations can be converged in essentially the same number of iterations as that describing nonionized flows while not sacrificing the generality of the drift-diffusion model.

Atmospheric pressure air plasmas are often thought to be in local thermodynamic equilibrium owing to fast interspecies collisional exchange at high pressure. This assumption cannot be relied upon, particularly with respect to optical... more

Atmospheric pressure air plasmas are often thought to be in local thermodynamic equilibrium owing to fast interspecies collisional exchange at high pressure. This assumption cannot be relied upon, particularly with respect to optical diagnostics. Velocity gradients in flowing plasmas and/or elevated electron temperatures created by electrical discharges can result in large departures from chemical and thermal equilibrium. This paper reviews

We report on the characteristics of aluminium trihydrate filled poly(methyl methacrylate) composite (PMMA/ATH) coatings realised by plasma deposition at atmospheric pressure. For this purpose, PMMA/ATH powder was fed to a plasma jet where... more

We report on the characteristics of aluminium trihydrate filled poly(methyl methacrylate) composite (PMMA/ATH) coatings realised by plasma deposition at atmospheric pressure. For this purpose, PMMA/ATH powder was fed to a plasma jet where the process and carrier gas was compressed air. The deposited coatings were investigated by X-ray photoelectron spectroscopy and water contact angle measurements. Further, the raw material was characterised before deposition. It was found that, with respect to the raw material, aluminium was uncovered in the course of the plasma deposition process which can be explained by plasma-induced etching of the PMMA matrix. As a result, the wettability of plasma-deposited PMMA/ATH was significantly increased. Even though a uniform coating film could not be realised as ascertained by confocal laser scanning microscopy, the deposited coatings feature notably enhanced characteristics which could be advantageous for further processing.

Combinations of wood and metal are interesting hybrid composite materials, joining together the low density of wood with the stiffness and strength of metals. Different types of adhesives are used to connect wood and metal elements, but... more

Combinations of wood and metal are interesting hybrid composite materials, joining together the low density of wood with the stiffness and strength of metals. Different types of adhesives are used to connect wood and metal elements, but the compatibility between adhesives used and load-bearing materials must be sufficient, which often is challenging. In adhesive bonding technology, surface treatments are a crucial step in the process. In this study, an atmospheric plasma discharge was employed to enhance the adhesion strength of joints between common beech (Fagus sylvatica L.) wood, metals (steel and aluminum alloy), and four different types of adhesives. The optical properties of plasma discharges and its influence on treated substrates' surface morphology depended on the inherent properties of the treated materials. X-ray photoelectron spectroscopy revealed the surface oxidation of all the materials after plasma treatment. Consequently, the surface free energy of all materials increased as well. The positive effect of the plasma treatment on the tensile shear strength of single-lap joints shows a high potential of atmospheric plasma treatment technology for enhancement of adhesives strength of joints combining wooden elements, wood and steel, or wood and aluminum alloys. In addition to that, expensive epoxy and polyurethane adhesives could be replaced by more affordable polyvinyl acetate and melamine-urea-formaldehyde adhesives, and still perform at equal levels if the plasma was applied prior to bonding.

This study examines the effects of an atmospheric pressure plasma (APP) pre‐treatment on the shrink resistance of wool fabric treated subsequently, by the pad/dry method, with an aqueous emulsion of the amino‐functional... more

This study examines the effects of an atmospheric pressure plasma (APP) pre‐treatment on the shrink resistance of wool fabric treated subsequently, by the pad/dry method, with an aqueous emulsion of the amino‐functional polydimethylsiloxane, SM 8709. Optimal shrink resistance (with no impairment of fabric handle) was obtained after a low‐level plasma treatment (1–3 s exposure time), using 5% of the polymer emulsion. Higher levels of silicone polymer could be used to achieve shrink resistance in the absence of a plasma pre‐treatment, but the fabric handle would be adversely affected. X‐ray photoelectron spectroscopy (XPS) studies showed that the bulk of the covalently bound surface lipid layer was removed after a plasma exposure time of 30 s. For treatment times of 3 s or less, however, the removal was incomplete, suggesting that optimum shrink resistance (after treatment with the silicone polymer) was associated with the modification of the surface layer rather than its complete destruction. Scanning electron micrographs (SEMs) revealed that the plasma pre‐treatment did not lead to any physical modifications (such as smoothening of the scale edges), even for long exposure times, and had no significant impact on the extent or nature of the inter‐fibre bonding of the polymer. Confocal microscopy showed uniform spread of polymer on single fibres. It is concluded that the main impact of the plasma pre‐treatment was to enhance the distribution of polymer both on and between fibres and to improve adhesion of polymer to the fibre.

A waveguide-based microwave plasma system was built using a resonant cavity and a quartz tube. 2.45 GHz 850 W magnetron was used to obtain helium discharge without an igniter. The temporal images of discharge were recorded on microsecond... more

A waveguide-based microwave plasma system was built using a resonant cavity and a quartz tube. 2.45 GHz 850 W magnetron was used to obtain helium discharge without an igniter. The temporal images of discharge were recorded on microsecond time scales using an intensified charge-coupled device camera. The excitation temperature was calculated as 3385 K using the helium lines, which were obtained from emission spectrum of the discharge. The gas temperature was measured as 1208 K by a thermocouple.

Polypropylene (PP) fabrics were activated by an atmospheric pressure, dielectric barrier discharge to optimize the effects of some discharge parameters on the dyeability of PP fabrics. Air and argon plasmas were used to modify the... more

Polypropylene (PP) fabrics were activated by an atmospheric pressure, dielectric barrier discharge to optimize the effects of some discharge parameters on the dyeability of PP fabrics. Air and argon plasmas were used to modify the surfaces of the fabrics, and the effects on dyeability were investigated when the treated fabrics were dyed by leuco and pigment forms of vat dyestuffs. Surface properties of plasma-treated samples were characterized by Fourier transform infrared spectroscopy (FTIR-ATR), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). Vat-dyed samples showed a significant increase in color strength when PP fabrics were pretreated with atmospheric pressure plasmas of either argon or air.

Atmospheric Pressure Plasma (APP) is being used widely in a variety of biomedical applications. Extensive research in the field of plasma medicine has shown the induction of DNA damage by APP in a dose-dependent manner in both prokaryotic... more

Atmospheric Pressure Plasma (APP) is being used widely in a variety of biomedical applications. Extensive research in the field of plasma medicine has shown the induction of DNA damage by APP in a dose-dependent manner in both prokaryotic and eukaryotic systems. Recent evidence suggests that APP-induced DNA damage shows potential benefits in many applications, such as sterilization and cancer therapy. However, in several other applications, such as wound healing and dentistry, DNA damage can be detrimental. This review reports on the extensive investigations devoted to APP interactions with DNA, with an emphasis on the critical role of reactive species in plasma-induced damage to DNA. The review consists of three main sections dedicated to fundamental knowledge of the interactions of reactive oxygen species (ROS)/reactive nitrogen species (RNS) with DNA and its components, as well as the effects of APP on isolated and cellular DNA in prokaryotes and eukaryotes.