Plasma activated water is a chemically active aqueous medium characterized by the presence of reactive oxygen and nitrogen species created by plasma exposure. This particular chemical composition is the starting point of extensive research studies in several domains such as bio-disinfectant in biomedical applications or as fertilizer in agricultural applications. These various applications need adjustments of the PAW properties and consequently require a better control of the PAW chemical composition. To achieve this aim, a UV spectrophotometric method (190–255 nm) is implemented to simultaneously detect the nitrate and nitrite ions in plasma activated water by a gliding arc discharge reactor at atmospheric pressure. The method, tested in plasma activated distilled water (PADW) and in plasma activated tap water (PATW), shows significant increases of nitrite and nitrate concentrations. Preliminary results on PADW and PATW kinetics evolutions highlight a different behavior of the temporal post-discharge reactions leading to non-conversion of the nitrite ions in the case of PATW. The near non-existence of acidification during and after plasma activation encountered in PATW is due to high levels of carbonate species in tap water acting as a buffer solution. Indeed, the presence of hydrogen carbonate (HCO₃⁻) leads to the acidity consumption during plasma activation whereas the presence of non-dissolved limestone in hard water (CaCO₃) acts as carbonates reserve, and this induces the acidity consumption after plasma treatment.

This study aims to present the properties of the polymeric films after being subjected to DBD plasma treatment in atmospheric conditions. Three different commercial films of polyester (Xerox Inkjet transparencies and Autostat CUS5 Clear film) and polycarbonate (Lexan™ 8010 MC) have been considered for the tests. The surface wettability has been evaluated based on static water contact angle (WCA) for different treatment times varying between 0.2 s and 30 s, the results revealing a maximum WCA decrease compared to a pristine of up to 50% for Xerox films, 75% for Autostat and 70% for Lexan. The persistence of the hydrophilic effect induced by the plasma treatment has also been verified for up to 72 h of storage after treatment, the results indicating a degradation of the treatment effects starting with the first hours after the treatment. The WCA stabilizes to a value inferior to the one corresponding to pristine in the first 24 h after plasma treatment. The adhesion forces, as well as preliminary surface morphology evaluations have been determined for the considered films using atomic force microscopy (AFM). The adhesion forces are increased together with the prolongation of the plasma treatment application time, varying from initial values of 165 nN, 58 nN and 204 nN to around 390 nN, 160 nN and 375 nN for Xerox, Autostat and Lexan films, respectively, after 5 s of DBD treatment. For the considered materials, the results revealed that the plasma treatment determines morphological changes of the surfaces indicating an increase in surface roughness.

Polytetrafluoroethylene (PTFE) is a potential candidate for the fabrication of flexible electronics devices and electronics with applications in various extreme environments, mainly due to its outstanding chemical and physical properties. However, to date, the utilization of PTFE in printing trials has been limited due to the material’s low surface tension and wettability, which do not ensure good adhesion of the printing ink at the level of the substrate. Within this paper, successful printing of PTFE is realized after pre-treating the surface of the substrate with the help of dielectric barrier discharge non-thermal plasma. The efficiency of the pre-treatment is demonstrated with respect to both silver- and carbon-based inks that are commercially available, and finally, the long-lasting pre-treatment effect is demonstrated for periods of time spanning from minutes to days. The experimental results are practically paving the way toward large-scale utilization of PTFE as substrate in fabricating printed electronics in harsh working environments. After 3 s of plasma treatment of the foil, the WCA decreased from approximately 103° to approximately 70°. The resolution of the printed lines of carbon ink was not time dependent and was unmodified, even if the printing was realized within 1 min from the time of applying the pre-treatment or 10 days later. The evaluation of the surface tension (σ) measured with Arcotest Ink Pink showed an increase in σ up to 40 < σ < 42 mN/m for treated Teflon foil and from σ < 30 mN/m corresponding to the untreated substrate. The difference in resolution was distinguishable when increasing the width of the printed lines from 500 μm to 750 μm, but when increasing the width from 750 μm to 1000 μm, the difference was minimal.

The present study aimed to investigate the effects of non-thermal plasma-activated water (PAW) on Triticum aestivum L. cv. Glosa sprouts. Two types of PAW were generated by exposing distilled water to a high-voltage electric discharge. Wheat caryopses were treated either with PAW1 (25 mg/L NO₃⁻, 4 mg/L NO₂⁻, and 6 mg/L H₂O₂) or PAW2 (35 mg/L NO₃⁻, 5 mg/L NO₂⁻, and 7.5 mg/L H₂O₂) for 8 days, with samples being collected at days 1, 2, 3, and 8. The germination rate, growth parameters, protein, photosynthetic pigments, total phenolic contents, antioxidant activity of free and bound phenolic fractions, and activity of antioxidant enzymes were evaluated. Both PAW1 and PAW2 had positive effects on Triticum aestivum L. cv. Glosa sprouts. PAW2 had a better impact on sprouts with respect to growth parameters, free phenolic content, and antioxidant activity of the free phenolic fraction (day 3), the accumulation of proteins, and photosynthetic pigments (day 8). In conclusion, exposure to PAW increases the quality of Triticum aestivum L. cv. Glosa sprouts. Further optimization of PAW treatment is required for the most favorable impact on the accumulation of biomass and health-promoting compounds in sprouts.

Non-thermal plasma-activated water (PAW) is used in agriculture to decontaminate the seed/grains surface, with possible positive effects on physiological processes. In the present study, PAW was generated in ambient air at atmospheric pressure in eight variants with pH and different doses of reactive species (H₂O₂, NO₃⁻). We explored the indirect effect of PAW on wheat grains while focusing on genetic material by cytogenetic monitoring. All PAW variants caused clastogenic and aneugenic events of the genetic material, with different intensities, in a dose-dependent manner of reactive species in plasma composition. PAW with the highest doses of H₂O₂ (13–22 mg/L) and NO₃⁻ (49–68 mg/L) at pH 3.8–4.1 decreased the mitotic index the most and induced the most frequent genetic abnormalities, out of which chromosomal bridges and micronuclei were dominant. In correlation with this damage at the nucleus level, the germination rate and root and shoot length of wheat sprouts decreased significantly only in the variants with the highest doses of reactive species. PAW with the lowest doses of H₂O₂ (1–5 mg/L) and NO₃⁻ (8–15 mg/L) at pH 5.5–5.1 induced a much lower cytogenotoxic potential, maintained a germination rate comparable to the control and even significantly stimulated root and shoot length growth. Thus, the effects of PAW depend highly on the dose of reactive species and on pH.

The scale up of nonthermal plasma (NTP) reactors requires the simultaneous operation in parallel of a large number of units supplied from the same power supply. The present paper aims to demonstrate the feasibility of parallel operation of multiple mini-NTP reactors. In order to demonstrate the parallel operation of a large number of NTP reactors, three different types of power supplies are considered. In addition to the most simple and common solution, which involves the use of individual, independent power supply for each reactor (an ignition coil driven by a pulse generator), two other configurations of supplies (capacitive AC and capacitive DC), simpler and less expensive, are tested. The capacitive pulsed power supplies allow the generation of HV pulses by an AC power supply (usually an AC transformer), as well as by a DC power supply using an R–C circuit. For the DC resistive–capacitive configuration, the frequency can be adjusted. For all configurations, the power of the discharge can be modified by changing the value of capacitors or resistors. The feasibility of the proposed systems was demonstrated by assessing the concentration of hydrogen peroxide induced in water after plasma treatment. The obtained results reveal that the proposed capacitive AC and DC power supplies allow a large number of plasma reactors to operate in parallel independently.