Short Plasma Exposure Research Articles

Evolution of pre-damaged ITER grade plasma facing components under WEST plasma exposure: smoothing and tungsten sources

The evaluation of the impact of plasma-facing units (PFUs) damage on subsequent plasma operation is an important issue for ITER. This is one of the topic addressed by the operation of dedicated PFUs in WEST. From the start of WEST in 2017, few ITER grade divertor PFUs were tested in the lower divertor for short plasma exposure (experimental campaigns C1–C5). A PFU is an assembly of tungsten blocks on CuCrZr tube via pure copper interlayer. Since 2022, WEST operates with a lower divertor fully equipped with ITER grade PFUs (experimental campaign C6–C7) with long duration plasma exposure capabilities. To test the ageing of the ITER-grade PFUs on an accelerated basis, well controlled damage was implemented on purpose with electron beam loading on the plasma facing surface of two different PFUs (pre-damage#1 and #2 featuring different level of damage). Damage tackled in this study is induced by the loading with numerous transient heat loading events to mimic the ELM impact on the ITER grade PFU. This paper presents the damage before and after WEST plasma exposure and shows the tungsten sources and temperature of the block measured during the operation. On damaged area, surface roughening is heterogeneous. With WEST campaigns (C3, C4 and C7) respectively ended in (2018, 2019 and 2023) a global smoothing of the pre-damaged surfaces, in particular those located in the high loaded erosion area, is observed. No evolution of the crack is observed in the electron beam loaded area, while new cracking are observed on non pre-damaged area on the tungsten top surfaces in highly loaded areas (outer strike point) after significant plasma duration and cumulated energy (first observation in C4 and tends to be confirmed with preliminary observations after the C7 campaign). Smoothing is less pronounced after the 2018 campaign, which may be due to the related short plasma duration. The surface smoothing of blocks also depends on their poloidal position. For PFU which has no shaping, toroidal positioning within a block has no influence on the surface smoothing. After 2019 and 2023 campaigns, equivalent relative smoothing is obtained (between 19 and 32%). For the explored plasma conditions, damage has no influence on the maximum brightness of W.

Excellent conformality of atmospheric-pressure plasma-enhanced spatial atomic layer deposition with subsecond plasma exposure times

Atmospheric-pressure spatial atomic layer deposition (s-ALD) has emerged as a scalable deposition technique combining the advantages of ALD with high deposition rates, suitable for low-cost and high-volume applications. There is a growing interest in atmospheric-pressure plasma-enhanced spatial ALD (PE-s-ALD), e.g., to allow for deposition at reduced temperatures or for materials that are otherwise difficult to prepare by thermal ALD. For low-pressure PE-ALD, conformal films on high aspect ratio features have been achieved despite plasma radical recombination, and the aspects influencing conformality are fairly well understood. This work addresses surface recombination and conformality for atmospheric-pressure PE-s-ALD films. We demonstrate that conformality can be achieved for SiO2 and TiO2 films deposited by atmospheric-pressure PE-s-ALD inside high-aspect-ratio trenches with short plasma exposure times. Using plasma exposure of 0.73 s results in conformal SiO2 and TiO2 films in structures with aspect ratios of 74 and 219, respectively. Additionally, the recombination probabilities of oxygen radicals at atmospheric pressure are extracted to be 4×10−4 for SiO2 and 6×10−5 for TiO2. These results demonstrate that atmospheric-pressure PE-s-ALD can be used for conformal and high-speed depositions on 3D substrates.

Non-Thermal Atmospheric Pressure Plasma Application in Endodontics.

The failure of endodontic treatment is frequently associated with the presence of remaining microorganisms, mainly due to the difficulty of eliminating the biofilm and the limitation of conventional irrigation solutions. Non-thermal atmospheric pressure plasma (NTPP) has been suggested for many applications in the medical field and can be applied directly to biological surfaces or indirectly through activated liquids. This literature review aims to evaluate the potential of NTPP application in Endodontics. A search in the databases Lilacs, Pubmed, and Ebsco was performed. Seventeen manuscripts published between 2007 and 2022 that followed our established inclusion criteria were found. The selected manuscripts evaluated the use of NTPP regarding its antimicrobial activity, in the direct exposure and indirect method, i.e., plasma-activated liquid. Of these, 15 used direct exposure. Different parameters, such as working gas and distance from the apparatus to the substrate, were evaluated in vitro and ex vivo. NTPP showed a disinfection property against important endodontic microorganisms, mainly Enterococcus faecalis and Candida albicans. The antimicrobial potential was dependent on plasma exposure time, with the highest antimicrobial effects over eight minutes of exposure. Interestingly, the association of NTPP and conventional antimicrobial solutions, in general, was shown to be more effective than both treatments separately. This association showed antimicrobial results with a short plasma exposure time, what could be interesting in clinical practice. However, considering the lack of standardization of the direct exposure parameters and few studies about plasma-activated liquids, more studies in the area for endodontic purposes are still required.

Adhesion improvement on the inner side of LLDPE/PA tubular film exposed to DCSBD roll‐to‐roll plasma system from the outer side of the film

AbstractDiffuse coplanar surface barrier discharge (DCSBD) was used to activate the opposite side of the plasma‐exposed linear low‐density polyethylene/polyamide (LLDPE/PA) tubular film of multilayer casing. We determined that conductive metal rubber roller in the DCSBD system allowed the formation of microfilaments perpendicular to the film surface, resulting in improved wettability and adhesion of inner LLDPE side of the tubular film. These findings were supported by increasing the concentration of polar functional groups. Based on these remarkable outcomes obtained after a very short plasma exposure time of 0.5 s, DCSBD roll‐to‐roll system in proper arrangement affords adhesion improvement of the opposite side of the treated film without any material damage, hence can compete with industrial corona in commercial sphere of plasma treatments.

Photoresponse of O2 plasma treated WS2 monolayers synthesized by chemical vapor deposition

WS2 monolayers synthesized by chemical vapor deposition underwent low-power O2 plasma treatment, and the effect of this treatment was studied in this work. The results show that the WS2 photoresponse is quenched due to the treatment and subsequently vanishes for more extended periods of plasma exposure. Raman spectra of the treated WS2 monolayers show that the position of the LA(M) mode is blueshifted and has a larger FWHM when compared with pristine samples. Since the LA(M) phonon can be used as a figure of merit to infer indirectly a density of defects in the lattice, these results show an increase in defects upon treatment times. At the same time, the main E2g and A1g peak positions remain nearly unchanged for short plasma exposures, indicating that there is an intrinsic defect-related process rather than a strain-related change. X-ray photoelectron spectroscopy results reveal the presence of O impurities incorporated into lattice passivating sulfur vacancies, while atomic force microscopy confirms that the sample creates cracks at the micrometer scale. Our results indicate that the pure oxygen plasma treatment significantly reduces the photoresponse of WS2 monolayers by increasing the density of defects.

Understanding the effect of nitrosylation on dynamics of human epidermal growth factor: a µs simulation study

Advancements in plasma science, such as the development cold atmospheric plasmas made it possible to easily generate reactive oxygen and nitrogen species (RONS) and apply them onto biological media at ambient conditions. Studying the interactions of RONS with biomolecules is a central topic of plasma medicine. One of the main targets of plasma medicine is to take control over signaling proteins such as human epidermal growth factor (hEGF) which is important protein in cancer treatment and wound healing. The oxidative damage of RONS on various proteins, including hEGF, was investigated using molecular dynamics (MD) simulations. However, another effect of RONS—nitrosative damage—is left unexplored. Plasma treatment can induce substantial damage via nitrosylation by reactive nitrogen species. Thus, elucidating effects of nitrosylation on protein structures is crucial, especially in plasma medicine. Here, we perform MD simulations to explore the effect of nitrosylation on the conformation of hEGF. We carried out MD simulations with different degrees of modifications of hEGF structures to mimic short and long plasma exposure times. Our results show that the nitrosylation induces conformational changes in hEGF and the breakage of disulfide bonds which might modulate binding of hEGF with its receptor. But the structural stability of hEGF remains almost unchallenged to the nitrosative damage, even to the disruption of disulfide bonds. The results assist plasma medicine applications in cancer treatment and wound healing by modulating plasma treatment time and chemical compositions of plasma-generated RONS to mediate effective oxidation of biological environment and develop optimal treatment protocols.

Designing Multifunctional Cobalt Oxide Layers for Efficient and Stable Electrochemical Oxygen Evolution

AbstractDisordered and porous metal oxides are promising earth‐abundant and cost‐effective alternatives to noble‐metal electrocatalysts. Herein, nonsaturated oxidation in plasma‐enhanced atomic layer deposition is leveraged to tune the structural, mechanical, and optical properties of biphasic cobalt hydroxide films, thereby tailoring their catalytic activities and chemical stabilities. Short oxygen plasma exposure times and low plasma powers incompletely oxidize the cobaltocene precursor to Co(OH)2 and result in carbon impurity incorporation. These Co(OH)2 films are highly porous and catalytically active, but their electrochemical stability is impacted by poor substrate adhesion. In contrast, long exposure times and high powers completely oxidize the precursor to Co3O4, reduce the carbon incorporation, and improve the crystallinity. While the Co3O4 films have high electrochemical stability, they are characterized by low oxygen evolution reaction activity. To overcome these competing properties, the established relation between deposition parameters and functional film properties is applied to design bilayer films exhibiting simultaneously improved electrochemical performance and chemical stability. The bilayer films combine a highly active Co(OH)2 surface with a stable Co3O4 interface layer. These coatings exhibit minimal light absorption, thus making them suitable as protective catalytic layers on semiconductor light absorbers for application in photoelectrochemical devices.

JNJ-73763989 pharmacokinetics and safety: Liver-targeted siRNAs against hepatitis B virus, in Japanese and non-Japanese healthy adults, and combined with JNJ-56136379 and a nucleos(t)ide analogue in patients with chronic hepatitis B.

JNJ-73763989 comprises two hepatitis B virus (HBV)-specific, liver-targeted N-galactosamine-conjugated short interfering RNA triggers, JNJ-73763976 and JNJ-73763924. JNJ-73763989 pharmacokinetics, safety and tolerability were assessed in two phase 1 studies: Japanese (NCT04002752), and non-Japanese healthy participants and chronic hepatitis B (CHB) patients also receiving the HBV capsid assembly modulator JNJ-56136379 and a nucleos(t)ide analogue (NA) (NCT03365947). Healthy participant cohorts were double-blind and randomized to receive a single subcutaneous JNJ-73763989 dose (non-Japanese participants, 35, 100, 200, 300 or 400mg; Japanese participants, 25, 100 or 200mg) or placebo. JNJ-73763976 and JNJ-73763924 plasma concentrations were assessed over 48h. CHB patients received JNJ-73763989 200mg every 4weeks plus daily oral JNJ-56136379 250mg and NA in an open-label fashion. Safety and tolerability were assessed through Day 28 (healthy participants) or Day 112 (patients). Thirty non-Japanese (n = 4/dose; placebo, n = 10) and 24 Japanese healthy participants (n = 6/dose; placebo, n = 6) were randomized. JNJ-73763976 and JNJ-73763924 exposure generally increased in a dose-proportional manner. Mean plasma half-life was 4-9h. No differences between pharmacokinetic parameters were apparent between non-Japanese and Japanese healthy participants. In the 12 CHB patients, mean JNJ-73763976, JNJ-73763924 and JNJ-56136379 plasma concentrations 2h post-dose on Day 29 were 663, 269 and 14,718ng/mL, respectively. In both studies, all adverse events were mild/moderate. JNJ-73763976 and JNJ-73763924 had short plasma half-lives and exposure generally increased in a dose-proportional manner; there were no pharmacokinetic differences between Japanese and non-Japanese healthy adults. JNJ-73763989 with or without JNJ-56136379 and NA was generally safe and well tolerated.

PECVD SiNx Thin Films for Protecting Highly Reflective Silver Mirrors: Are They Better Than ALD AlOx Films?

Protection of silver surface from corrosion is an important topic, as this metal is highly susceptible to damage by atomic oxygen, halogenated, acidic and sulfur-containing molecules. Protective coatings need to be efficient at relatively small thicknesses, transparent and must not affect the surface in any detrimental way, during the deposition or over its lifetime. We compare PECVD-deposited SiNx films to efficiency of ALD-deposited AlOx films as protectors of front surface silver mirrors against damage by oxygen plasma. Films of different thickness were deposited at room temperature and exposed to O2 ECR-plasma for various durations. Results were analyzed with optical and SEM microscopy, pulsed GD-OES, spectroscopic ellipsometry and spectrophotometry on reflection. Studies indicate that both films provide protection after certain minimal thickness. While this critical thickness seems to be smaller for SiNx films during short plasma exposures, longer plasma treatment reveals that the local defects in PECVD-deposited films (most likely due to erosion of some regions of the film and pinholes) steadily multiply with time of treatment and lead to slow drop of reflectance of SiNx-protected mirrors, whereas we showed before that ALD-deposited AlOx films reliably protect silver surface during long plasma exposures.

The Effect of DBD Plasma Activation Time on the Dyeability of Woven Polyester Fabric with Disperse Dye.

This study consists of two parts. In the first, the woven polyester fabric, after washing to remove lubricant oils, was treated with the dielectric barrier discharge (DBD) plasma at the short plasma exposure time (from 15 to 90 s). The effect of the plasma exposure time on the activation of the polyester fabric was assessed by the wicking height of the samples. The results show that the wicking height in the warp direction of the plasma-treated samples improved but was virtually unchanged in the weft direction. Meanwhile, although the tensile strength in the warp direction of the fabric was virtually unaffected despite the plasma treatment time up to 90 s, in the weft direction it increased slightly with the plasma treatment time. Scanning Electron Microscope (SEM) images and the X-ray Photoelectron Spectroscopy (XPS) spectra of the samples before and after the plasma treatment were used to explain the nature of these phenomena. Based on the results of the first part, in the second part, two levels of the plasma treatment time (30 and 60 s) were selected to study their effect on the polyester fabric dyeability with disperse dyes. The color strength (K/S) values of the dyed samples were used to evaluate the dyeability of the fabric. The SEM images of the dyed samples also showed the difference in the dyeability between the plasma-treated and untreated samples. A new feature of this study is the DBD plasma treatment condition for polyester fabrics. The first is the use of DBD plasma in air (no addition of gas). Second is the very short plasma treatment time (only 15 to 90 s); this condition will be very favorable for the deployment on an industrial scale.

Efficacy of boron nitride encapsulation against plasma-processing of 2D semiconductor layers

Two-dimensional (2D) transition metal dichalcogenides (TMDCs) are the subject of intense investigation for applications in optics, electronics, catalysis, and energy storage. Their optical and electronic properties can be significantly enhanced when encapsulated in an environment that is free of charge disorder. Because hexagonal boron nitride (h-BN) is atomically thin, highly crystalline, and is a strong insulator, it is one of the most commonly used 2D materials to encapsulate and passivate TMDCs. In this report, we examine how ultrathin h-BN shields an underlying MoS2 TMDC layer from the energetic argon plasmas that are routinely used during semiconductor device fabrication and postprocessing. Aberration-corrected scanning transmission electron microscopy is used to analyze defect formation in both the h-BN and MoS2 layers, and these observations are correlated with Raman and photoluminescence spectroscopy. Our results highlight that h-BN is an effective barrier for short plasma exposures (<30 s) but is ineffective for longer exposures, which result in extensive knock-on damage and amorphization in the underlying MoS2.

Atomic layer deposition of LiF using LiN(SiMe3)2 and SF6 plasma.

Lithium fluoride films were prepared by atomic layer deposition (ALD) using a new route in which LiN(SiMe3)2 is used as a precursor and SF6 plasma as a coreactant. Conformal LiF films were deposited at 150 °C at a growth rate of ∼0.4 Å per cycle. All deposited films were polycrystalline and slightly lithium-rich with a composition of LiF0.8, independently of the plasma conditions (e.g. exposure time, pressure and power). The levels of H, C, N, O, Si, and S were all <1 at%. Spectroscopic ellipsometry measurements were carried out over the wavelength range of 140-2480 nm and showed a refractive index of 1.37 at 633 nm for films deposited using 1 s plasma exposure time. We conclude that short plasma exposures are preferred, since a prolonged exposure time leads to an increase in optical absorption and lower growth per cycle values. Furthermore, mass spectrometry measurements revealed the formation of SiMe3F species during both half-cycles, originating from the reaction between the precursor ligands and fluorine species present either at the surface or in the plasma. Moreover, the SF6 plasma step led to the formation of fluorocarbon species, suggesting that dissociation and recombination in the plasma takes place. Overall, this work demonstrates that SF6 plasma offers a promising alternative to other coreactants for ALD of high purity lithium fluoride.

Physicochemical surface analysis and germination at different irrigation conditions of DBD plasma‐treated wheat seeds

AbstractPlasma treatment is increasingly being explored as an effective presowing treatment improving seed germination. This study examines the synergetic effect of the irrigation condition and the physicochemical surface properties of wheat seeds subjected to atmospheric dielectric barrier discharge plasma activation on their water uptake and germination. Extensive surface analysis revealed a remarkably enhanced wettability of plasma‐treated seeds due to the insertion of oxygen‐containing functionalities on their surface. However, long plasma exposures damaged the outermost layers of the pericarp due to a pronounced oxidative etching effect. Although the seed germination capacity was not affected by the plasma treatments, short plasma exposures were shown to enhance water uptake and accelerate seed germination, especially under water‐scarcity conditions.

Electrical properties tunability of large area MoS2 thin films by oxygen plasma treatment

MoS2 thin films prepared via sulfurization of molybdenum films have attracted great attention due to their advantage for scalable synthesis with a large area coverage. However, the MoS2 thin films are typically more resistive than their exfoliated and co-evaporation chemical vapor deposition based counterparts. The ability to modulate the electrical property of MoS2 thin films will have a significant impact on scalable device applications in electronics, sensors, and catalysis. Here, we report the tuning of electrical transport properties of large area MoS2 thin films with different oxygen plasma exposure times. The electrical transport measurements of the pristine and plasma treated samples reveal that with increasing oxygen plasma treatment, the resistance of the MoS2 thin films first decreases by almost an order of magnitude and then increases again. The x-ray photoelectron spectroscopy measurements show that the S:Mo ratio continuously decreases with increasing plasma exposure time. For a short plasma exposure time, the resistance decrease can be explained due to the creation of sulfur vacancies leaving unsaturated electrons with molybdenum (Mo) atoms which act as electron donors. With increasing plasma exposure, more sulfur vacancies and hence more Mo atoms are created, many of which get converted to insulating MoO3 resulting in an increase in the resistance of the MoS2 thin film. The results presented here are a major step forward in realizing the overreaching goals of MoS2 thin films for practical device applications.

Atmospheric pressure non-thermal plasma exposure reduces Pseudomonas aeruginosa lipopolysaccharide toxicity in vitro and in vivo

Lipopolysaccharide (LPS) is an endotoxin composed of a polysaccharide and lipid component. It is intrinsically responsible for the pathogenicity of Gram-negative bacteria and is involved in the development of bacterial sepsis. Atmospheric pressure non-thermal plasma is proposed as a potential new approach for the treatment of infected tissue such as chronic wounds, with both antibacterial and wound-healing activities extensively described. Using both the RAW264.7 murine macrophage cell line in vitro assays and the Galleria mellonella insect in vivo toxicity model, the effect non-thermal plasma exposure on LPS-mediated toxicity has been characterised. Short (60 s) non-thermal plasma exposures of Pseudomonas aeruginosa conditioned growth media, membrane lysates and purified P. aeruginosa LPS, resulted in a substantial detoxification and reduction of LPS-induced cytotoxicity in RAW264.7 murine macrophages. Non-thermal plasma exposure (60 s) of purified P. aeruginosa LPS led to a significant (p < 0.05) improvement in the G. mellonella health index (GHI) score, a measure of in vivo toxicity. These findings demonstrate the ability of short plasma exposures to significantly reduce LPS-induced cytotoxicity both in vitro and in vivo; attenuating the toxicity of this important virulence factor intrinsic to the pathogenicity of Gram-negative bacteria.

Stimulation of the Germination and Early Growth of Tomato Seeds by Non-thermal Plasma

The influence of non-thermal plasma on tomato seeds has been investigated using a fluidized bed dielectric barrier discharge generated in air. It was found that plasma-treated seeds germinate faster than untreated ones. Plasma slightly enhanced germination rate and considerably influenced growth parameters. Seedling length and weight are significantly higher than those of untreated seeds. The influence of plasma exposure is more visible on the plant roots, which are substantially longer and more branched. An increase in weight of 20–40% was observed for the plants grown from treated seeds as compared to the control ones. The best results are obtained for relatively short plasma exposure, while too long treatment appears to be detrimental to the seeds.

Simple plasma assisted atomic layer deposition technique for high substitutional nitrogen doping of TiO2

In this work, a plasma assisted atomic layer deposition system was used to deposit nitrogen-doped titanium dioxide. A simple approach was developed that requires only a nitrogen plasma and short plasma exposure times to effectively dope TiO2. A range of nitrogen concentrations were achieved by varying the flow rate and exposure times of nitrogen and oxygen plasmas. A nitrogen content as high as 23 ± 0.5 at. % was observed when only the nitrogen plasma was used. It was also possible to vary the type of nitrogen doping from almost entirely interstitial to purely substitutional, as measured by x-ray photoelectron spectroscopy. Ultraviolet-visible spectroscopy measurements showed a shifting in the absorption edge from 350 to 520 nm with doping, indicating bandgap narrowing from 3.1 to 1.9 eV.

Surface martensitization of Carbon steel using Arc Plasma Sintering

In this paper new technology of surface structure modification of steel by short plasma exposure in Arc Plasma Sintering (APS) device is presented. APS is an apparatus working based on plasma generated by DC pulsed current originally used for synthesizing materials via sintering and melting. Plasma exposure in APS was applied into the specimens for 1 and 3 seconds which generate temperature approximately about 1300-1500°C. The SUP9, pearlitic carbon steel samples were used. The hardness, hardening depth and microstructure of the specimens have been investigated by Vickers micro hardness test and Scanning Electron Microscopy (SEM) supported by Energy Dispersive X-Ray Spectroscopy (EDX). The results have showed that the mechanical property was significantly improved due to the formation of single martensitic structures as identified by SEM. The hardness of treated surface evaluated by Vickers hardness test showed significant improvement nearly three time from 190 VHN before to 524 VHN after treatment. Furthermore, EDX confirmed that the formation of martensite layer occurred without altering its composition. The APS also produced uniform hardened layer up to 250 μm. The experiment has demonstrated that arc plasma process was successfully improved the mechanical properties of steel in relatively very short time.

Investigating Electron And Radical Interactions With Biomolecules And Cells Using A Droplet In Plasma Laboratory

Plasmas-liquid interactions are a valuable source of radical species for plasma medicine including cancer treatment and antimicrobial applications. However untangling the complex interplay between species and biology over very short timescales and distances is proving extremely challenging. Radiolysis induced damage to DNA is considered to be significantly affected by low energy secondary species such as OH radicals but also via direct interaction with low energy solvated electrons (LEE). Pt adducts and the presence of Au nanoparticles are also known to enhance the LEE effectiveness. However direct investigation of LEE and radical interactions with biomolecules e.g. DNA in a liquid environment at atmospheric pressure or in a living cell present very significant experimental challenges. LEE sources have been proposed such as 2D radioactive layers and UV-induced emission from metals. In this work we look at the potential of a living laboratory based on small liquid droplets containing biomolecules or cells passed through a plasma and exposed to a high flux of electrons and selectable radicals. We also consider the potential of using droplets to deliver plasma-activated media near instantaneously downstream. Transport of micron-sized liquid droplets through a low temperature non-equilibrium RF plasma [1] at atmospheric pressure has demonstrated a number of remarkable and unexpected effects. The microdroplet system allows for a controlled (air-free) gas ambient environment, a large surface area to volume ratio, very small reaction volume and low droplet temperature. In addition, flow induced convection in the liquid can be minimised. After a very short plasma exposure time, ~120°μ s, there is evidence that chemical reactions induced by the plasma and gas flux proceed at a rate that is significantly faster that observed in plasma – bulk liquid studies and many orders of magnitude faster than in standard bulk chemistry [2]. The high chemical reactivity is thought to depend not only on the picolitre droplet volume, as in microreaction chemistry, but also on the high level of surface charge due to net electron bombardment in the plasma and the high flux of low energy electrons which arrive at the charged droplet with almost zero net energy. We have observed very rapid electron reduction of metal (Au) salts to form Au nanoparticles at rates that are much greater than observed with gamma radiolysis or high energy electron beams. This points to the possible effectiveness of plasma-generated Ultra-Low Energy Electrons (ULEE) in reduction reactions that may prove valuable for electron – biomolecule studies. We have also observed H2O2 and OH in the liquid most likely due to generation of these species in the plasma phase, which contains only He and H2O vapour. We have used droplets as carriers for single bacteria cells, which are then exposed to plasma species (electrons, OH and H2O2) for a very short time (~0.1 ms) and the effects on cell viability and properties determined. It is clear that this system is complex but plasma-droplet system may yet offer unique access for plasma – liquid chemistry and biology studies. We will present plasma-DNA and cell studies in conjunction with liquid chemistry and electric field modelling.

Atmospheric pressure plasma assisted calcination by the preparation of TiO2 fibers in submicron scale

Atmospheric pressure plasma assisted calcination by the preparation of TiO2 submicron fibers as a low-temperature alternative to the conventional thermal annealing was studied. A special type of dielectric barrier discharge was used for plasma treatment of hybrid titanium butoxide/polyvinylpyrrolidone (Ti(Bu)/PVP) fibers prepared by forcespinning to decompose and oxidize the base polymer and precursor. The obtained fibers were characterized by changes in chemical bonds on the surface using Fourier Transform Infrared Spectroscopy (FTIR), chemical composition by using Energy-Dispersive X-Ray Spectroscopy (EDX), X-ray Photoelectron Spectroscopy (XPS). The morphology of fibers was investigated by Scanning Electron Microscopy (SEM). A significant decrease of organic components was reached by short plasma exposure times less than 1 h. The obtained fibers exhibit a high surface porosity without degradation of the fibrous structure. The results obtained indicate that atmospheric pressure plasma assisted calcination can be a viable low-temperature, energy-and time-saving alternative or pre-treatment method for the conventional high-temperature thermal calcination.