Comparative Physical and Physicochemical Characterization of Normal Saline Activated by two Atmospheric-pressure Plasma Systems

Controlling deposition rates in an atmospheric pressure plasma system

Atmospheric pressure plasma is now being widely developed for simple surface treatment process and for fast medical tools sterilization. Plasma surface modification involves the interaction of the plasma generated excited species with a solid interface or coatings. The previous vacuum plasma system is not applicable and very costly. In the present project, we have developed the high voltage power supply and atmospheric pressure plasma using dielectric barrier discharge concept. The high voltage power supply was developed using a simple 555 timer and car's ignition coil. Then, we investigate the plasma surface modification effect from the contact angle measurement and evaluate the roughness using surface profiler. We found that the contact angle decreased with the exposure time and surface roughness changed when exposed with atmospheric pressure plasma. It has been understood that a film coating will be create on glass and silicon surface when expose with atmospheric pressure plasma system in water vapor environment.

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.

Gas discharge plasmas used for thinfilm deposition by plasma-enhanced chemical vapor deposition (PECVD) must be devoid of contaminants, like dust or active species which disturb the intended chemical reaction. In atmospheric pressure plasma systems employing an inert gas, the main source of such contamination is the residual air inside the system. To enable the construction of an atmospheric pressure plasma (APP) system with minimal contamination, we have carried out fluid dynamic simulation of the APP chamber into which an inert gas is injected at different mass flow rates. On the basis of the simulation results, we have designed and built a simple, scaled APP system, which is capable of holding a 100 mm substrate wafer, so that the presence of air (contamination) in the APP chamber is minimized with as low a flow rate of argon as possible. This is examined systematically by examining optical emission from the plasma as a function of inert gas flow rate. It is found that optical emission from the plasma shows the presence of atmospheric air, if the inlet argon flow rate is lowered below 300 sccm. That there is minimal contamination of the APP reactor built here, was verified by conducting an atmospheric pressure PECVD process under acetylene flow, combined with argon flow at 100 sccm and 500 sccm. The deposition of a polymer coating is confirmed by infrared spectroscopy. X-ray photoelectron spectroscopy shows that the polymer coating contains only 5% of oxygen, which is comparable to the oxygen content in polymer deposits obtained in low-pressure PECVD systems.

Nonthermal atmospheric pressure plasma jets are becoming increasingly important in wastewater treatment applications. Especially, it is quite difficult to remove the color found in the wastewater of some industries such as textile and paint industries by traditional methods. Therefore, in the study, the color removal efficiency was investigated using atmospheric pressure plasma system. In the design of the system, an electric current is directed from a low pressure gas flow and an atmospheric plasma field is created. Treatment is achieved as a result of contact with the wastewater. In this study, the removal efficiencies of pomegranate wastewater and methyl orange (MO) as a model dye were investigated. Oxygen gas was studied as feed gas. Plasma discharge flow rate was applied as 12 mg/L, and plasma duration was 5 minutes. The results were evaluated for two different wastewaters. For an initial concentration of 20 mg/L, the COD removal efficiencies of methyl orange and pomegranate wastewater (PW) were found to be 83.7 and 98.4%, respectively. The highest color removal efficiency for methyl orange was calculated as 97%. In addition, Lepidium sativum toxicity test was used to determine whether there was any toxic effect due to radicals formed in the system. No toxic effects from the plasma system were observed. As a result, inspired by the studies conducted worldwide on the usability of plasma technology in water treatment, the usability of the atmospheric pressure plasma system, which is a new technology in the field of water treatment, was evaluated.

Investigation of novel low temperature atmospheric pressure plasma system for deposition photo-catalytic TiO 2 thin film

The topic of water reuse is becoming increasingly important. It might be possible to use the well-known antibacterial effect of atmospheric pressure plasma due to its special mixture of reactive species, UV, and electromagnetic fields in a scaled-up, industrially interesting area to remove bacteria from wastewater, and thus, make it usable again. To review this question, water volumes of 5L and of different qualities (turbidity and different degrees of hardness) were treated with a commercially available plasma system. The change in water-specific values such as pH, EC, ORP, nitrate, and nitrite content was determined. To test the antibacterial effect, both direct and indirect treatment of the test germ Pseudomonas aeruginosa was conducted. In the first case, the inoculated water samples were plasma-treated, while in the second case, the water samples were treated before inoculation with the germ. The viable bacteria were counted via the spread plate method. The best reduction rate of at least 6 log levels was achieved when inoculated deionized water samples were treated directly with plasma. A significant reduction in viability was also observed in directly treated clear tap water samples, whereby the different degrees of hardness did not influence the effectiveness of the plasma. The bacterial load remained almost unchanged when reused water samples from a car wash were treated. Based on the results, a possible application in a car wash was discussed including a cost estimation and possible limitations.

Atmospheric pressure plasma driven by Neon transformer power supply argon is presented in this paper. Atmospheric pressure plasma system has attracted researcher interest over low pressure plasma as it provides a flexibility process, cost-efficient, portable device and vacuum-free device. Besides, another golden key of this system is the wide promising application in the field of work cover from industrial and engineering to medical. However, there are still numbers of fundamental investigation that are necessary such as device configuration, gas configuration and its effect. Dielectric barrier discharge which is also known as atmospheric pressure plasma discharge is created when there is gas ionization process occur which enhance the movement of atom and electron and provide energetic particles. These energetic particles can provide modification and cleaning property to the sample surface due to the bombardment of the high reactive ion and radicals to the sample surface. In order to develop atmospheric pressure plasma discharge, a high voltage and high frequency power supply is needed. In this work, we used a neon transformer power supply as the power supply. The flow of the Ar is feed into 10 mm cylinder quartz tube with different treatment time in order to investigate the effect of the plasma discharge. The analysis of each treatment time is presented by optical emission spectroscopy (OES) and water contact angle (WCA) measurement. The increase of gas treatment time shows increases intensity of reactive Ar and reduces the angle of water droplets in water contact angle. Treatment time of 20 s microslide glass surface shows that the plasma needle discharges have modified the sample surface from hydrophilic surface to superhydrophilic surface. Thus, this leads to another interesting application in reducing sample surface adhesion to optimize productivity in the industry of paintings, semiconductor and more.

A set of real-time non-invasive multivariate analysis tools were evaluated using LabVIEW software for the process monitoring of an atmospheric pressure plasma system. During system operation, it was observed that the optical and electrical properties are subject to a deterministic jitter effect caused by momentary changes in the discharge characteristics. This temporal jitter in the voltage, current and frequency of the applied power to an atmospheric pressure plasma was monitored to assess the plasma processing conditions. Electrical diagnostic tools were used to determine the transition of the plasma from the primary glow mode to the secondary glow mode and were correlated with photo diode (PD) analysis of the plasma. Intensified charge-coupled device (ICCD) imaging of the plasma was also used to distinguish between glow and Townsend discharge properties at low applied powers (400 W). The electrical observations were recorded in real time, plotted on a principal component analysis (PCA) loading plot and analysed using non-parametric cluster analysis (NPCA). It was observed from the plotted electrical parameters that data clusters were formed which relate to both the geometry of the atmospheric plasma chambers and the mode of plasma operation. The development of these tools facilitates real-time analysis of this reel-to-reel atmospheric pressure plasma processing system.

Although an adhesive joint can distribute load over a larger area than a mechanical joint, requires no holes, adds very little weight to structures and has superior fatigue resistance, it requires careful surface preparation of adherends for reliable joining and low susceptibility to service environments. The load transmission capability of adhesive joints can be improved by increasing the surface free energy of the adherends with suitable surface treatments. In this study, two types of surface treatment, namely the low pressure and the atmospheric pressure plasma treatment, were performed to enhance the mechanical load transmission capabilities of carbon/epoxy composite adhesive joints. The suitable surface treatment conditions for carbon/epoxy composite adhesive joints for both low and atmospheric pressure plasma systems were experimentally investigated with respect to chamber pressure, power intensity and surface treatment time by measuring the surface free energies of the specimens. The change in surface topography of carbon/epoxy composites was measured with AFM (Atomic Force Microscopy) and quantitative surface atomic concentrations were determined with XPS (X-ray Photoelectron Spectroscopy) to investigate the failure modes of composite adhesive joints with respect to surface treatment time. From the XPS investigation of carbon/epoxy composites, it was found that the ratio of oxygen concentration to carbon concentration for both low and atmospheric pressure plasma-treated carbon/epoxy composite surfaces was maximum after about 30 s treatment time, which corresponded with the maximum load transmission capability of the composite adhesive joint.

We demonstrated high adhesive fluoropolymer/copper interface through combination of atmospheric pressure plasma with liquid phase self-assembly. However, there are some disadvantages in atmospheric pressure plasma technique, such as small processing area due to the localized plasma and high gas temperature. Medium pressure plasma process has some advantages over atmospheric pressure plasma systems. A large plasma volume and low gas temperature, available for surface treatment of polymer material, can be easier obtained at medium pressure than at atmospheric pressure, which can result in a higher overall productivity. In this paper, we investigated the adhesion strength of electroless copper plated layer formed on poly(tetrafluoroethylene-co-perfluoropropyl vinyl ether) (PFA) surface modified by combination of medium pressure helium plasma irradiation and aminated acrylic polymer grafting. The 90° peel test result for copper plating film formed on the treated PFA films showed the adhesion strength of 0.44 N/mm without increasing the surface roughness.

Indirect plasma inactivation by a low temperature atmospheric pressure plasma (LTAPP) system

Atmospheric pressure plasma treatment of amorphous polyethylene terephthalate for enhanced heatsealing properties

A new method for immunosensor preparation: Atmospheric plasma torch

Atmospheric pressure plasma systems are routinely used to treat the surfaces of thermally sensitive materials. There are wide ranges of commercial plasma jet systems available, and for the end user, it can be difficult to directly compare the power outputs of these sources. This paper evaluates the use of a thermal imaging technique in order to provide a semiquantitative evaluation of energy output from plasma jets. The evaluation involved a comparison of the thermal energy transfer obtained from three commercially available atmospheric pressure plasma jet systems: 1) PlasmaTreat's Openair; 2) Dow Corning's PlasmaStream; and 3) SurFx's Atomflo.