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In our study, plasma surface modification was employed to tailor the surface properties of magnesium in terms of surface chemistry, topography, and wettability. For two sets of samples, the plasma treatment involved two steps using two different gases (hydrogen and oxygen), while one set of samples was treated with one step only using oxygen. X-ray photoelectron spectroscopy (XPS) was applied to determine the surface composition, oxidation state of the elements, and the thickness of the surface oxide layer on the Mg samples after different plasma treatments. The surface morphology was characterised using atomic force microscopy (AFM) and scanning electron microscopy (SEM). The wettability was analysed by measuring the static water-contact angles and the corrosion was evaluated using potentiodynamic measurements. The interaction of the live cells with the differently modified Mg surfaces was evaluated in terms of biocompatibility using MG-63 cells (human bone osteosarcoma cells). We have shown that a plasma surface treatment significantly decreased the carbon content and the formation of a 15–20-nm-thick MgO layer was observed. This improves the corrosion resistance, while the biocompatibility was retained, compared to the untreated Mg. A plasma surface treatment is therefore an important step in the development of novel surfaces with improved corrosion resistance for magnesium in biomedical applications.

The interfacial interface between fibers and matrix plays a key role for epoxy matrix composites and short recycled randomly arranged fibers. This study used short recycled carbon fiber (RCF) as a filler. Plasma treatment was used for carbon fiber surface treatment. This treatment was performed using radio (RF) and microwave (MW) frequencies at the same pressure and atmosphere. Appropriate chemical modification of the fiber surfaces helps to improve the wettability of the carbon fibers and, at the same time, allows the necessary covalent bonds to form between fibers and the epoxy matrix. The effect of the plasma treatment was analyzed and confirmed by X-ray photoelectron spectroscopy, Raman microscopy, scanning electron microscopy, transmission electron microscopy and wettability measurements. Composite samples filled with recycled carbon fibers with low concentrations (1 wt%, 2.5 wt% and 5 wt%) and high concentrations (20 wt% and 30 wt%) were made from selected treated fibers. The mechanical properties (impact toughness, 3PB) were analyzed on these samples. It was found that the modulus of elasticity and bending stress increase with the increasing content of recycled carbon fibers. A more significant change in impact strength occurred in samples with low concentration.

The presence of defects in a catalyst support is known to benefit catalytic activity. In this work, a He-plasma treatment-based strategy for introducing and stabilising defects on a Ni/TiO2 catalyst for photothermal CO2 hydrogenation was established. The impact of pretreatment step sequence—which comprised He-plasma treatment and reduction/passivation—on defect generation and stabilisation within the support was evaluated. Characterisation of the Ni/TiO2 catalysts indicated that defects created in the TiO2 support during the initial plasma treatment stage were then stabilised by the reduction/passivation process, (P-R)Ni/TiO2. Conversely, performing reduction/passivation first, (R-P)Ni/TiO2, invoked a resistance to subsequent defect formation upon plasma treatment and consequently, poorer photothermal catalytic activity. The plasma treatment altered the metal-support interaction and ease of catalyst reduction. Under photothermal conditions, (P-R)Ni/TiO2 reached the highest methane production in 75 min, while (R-P)Ni/TiO2 required 165 min. Decoupling the impacts of light and heat indicated thermal dominance of the reaction with CO2 conversion observed from 200 °C onwards. Methane was the primary product with carbon monoxide detected at 350 °C (~2%) and 400 °C (~5%). Overall, the findings demonstrate the importance of pretreatment step sequence when utilising plasma treatment to generate active defect sites in a catalyst support.

The study investigated the effectiveness of the combination of chemical and physical methods of natural fibers’ modification. The long flax fibers were subjected to various types of modification. These were silanization, plasma modification and a combination of these methods. For the silanization process, two types of silanes were used: amino- and vinylsilane. The application of structurally different compounds allowed us to acquire knowledge about the effect of the modifier structure on its properties. Various properties of flax fibers were investigated, comparing the results before and after different modification processes. The flammability of prepared samples were tested by pyrolysis combustion flow calorimeter (PCFC). In the effect of the natural fibers’ modifications, flammability was reduced even by 30%. The thermal stability of modified fibers increased. The FTIR tests of the gases released during thermal degradation of the tested fibers allowed us to determine the important compounds and prove a lower degree of flax-fiber decomposition after modification. Flax fibers were also tested to evaluate their physical properties (linear mass, average diameter, aspect ratio and hygroscopicity). Changes in surface morphology were observed by scanning electron microscope (SEM). The properties of natural fibers improved significantly, thus contributing to an increase in their suitability for the use in composites.

Organic solvents used for electrolytes of dye-sensitized solar cells (DSSCs) are generally not only toxic and explosive but also prone to leakage due to volatility and low surface tension. The representative dyes of DSSCs are ruthenium-complex molecules, which are expensive and require a complicated synthesis process. In this paper, the eco-friendly DSSCs were presented based on water-based electrolytes and a commercially available organic dye. The effect of aging time after the device fabrication and the electrolyte composition on the photovoltaic performance of the eco-friendly DSSCs were investigated. Plasma treatment of TiO2 was adopted to improve the dye adsorption as well as the wettability of the water-based electrolytes on TiO2. It turned out that the plasma treatment was an effective way of improving the photovoltaic performance of the eco-friendly DSSCs by increasing the efficiency by 3.4 times. For more eco-friendly DSSCs, the organic-synthetic dye was replaced by chlorophyll extracted from spinach. With the plasma treatment, the efficiency of the eco-friendly DSSCs based on water-electrolytes and chlorophyll was comparable to those of the previously reported chlorophyll-based DSSCs with non-aqueous electrolytes.

The low quality of adhesion performance on polymeric surfaces has forced the development of specific pretreatments able to toughen the interface between substrate and adhesive. Among these methods, atmospheric pressure plasma treatment (APPT) appears particularly suitable for its environmental compatibility and its effectiveness in altering the chemical state of the surface. In this work, an experimental study on adhesively bonded joints realized using polyamide as substrates and polyurethane as the structural adhesive was carried out with the intent to characterize their fatigue behavior, which represents a key issue of such joints during their working life. The single lap joint (SLJ) geometry was chosen and several surface pretreatments were compared with each other: degreasing, abrasion (alone and followed by APPT) and finally APPT. The results show that the abrasion combined with APPT presents the most promising behavior, which appears consistent with the higher percentage of life spent for crack propagation found by means of DIC on this class of joints with respect to the others. APPT alone confers a good fatigue resistance with respect to the simple abrasion, especially at a low number of cycles to failure.

The development of new biocompatible polymer substrates is still of interest to many research teams. We aimed to combine a plasma treatment of fluorinated ethylene propylene (FEP) substrate with a technique of improved phase separation. Plasma exposure served for substrate activation and modification of surface properties, such as roughness, chemistry, and wettability. The treated FEP substrate was applied for the growth of a honeycomb-like pattern from polystyrene solution. The properties of the pattern strongly depended on the primary plasma exposure of the FEP substrate. The physico-chemical properties such as changes of the surface chemistry, wettability, and morphology of the prepared pattern were determined. The cell response of primary fibroblasts and osteoblasts was studied on a honeycomb pattern. The prepared honeycomb-like pattern from polystyrene showed an increase in cell viability and a positive effect on cell adhesion and proliferation for both primary fibroblasts and osteoblasts.

To improve the chemical durability of SiC-based coatings on glass-ceramics, the effects of annealing and N2 plasma treatment were investigated. Fluorapatite glass-ceramic disks were coated with SiC via plasma-enhanced chemical vapor deposition (PECVD), treated with N2 plasma followed by an annealing step, characterized, and then immersed in a pH 10 buffer solution for 30 days to study coating delamination. Post-deposition annealing was found to densify the deposited SiC and lessen SiC delamination during the pH 10 immersion. When the SiC was treated with a N2 plasma for 10 min, the bulk properties of the SiC coating were not affected but surface pores were sealed, slightly improving the SiC&rsquo, s chemical durability. By combining N2 plasma-treatment with a post-deposition annealing step, film delamination was reduced from 94% to 2.9% after immersion in a pH 10 solution for 30 days. X-ray Photoelectron spectroscopy (XPS) detected a higher concentration of oxygen on the surface of the plasma treated films, indicating a thin SiO2 layer was formed and could have assisted in pore sealing. In conclusion, post-deposition annealing and N2 plasma treatment where shown to significantly improve the chemical durability of PECVD deposited SiC films used as a coating for glass-ceramics.

Plasma treatment is one of the most promising tools to control surface properties of materials tailored for biomedical application. Among a variety of processing conditions, such as the nature of the working gas and time of treatment, discharge type is rarely studied, because it is mainly fixed by equipment used. This study aimed to investigate the effect of discharge type (direct vs. alternated current) using air as the working gas on plasma treatment of poly(ethylene terephthalate) films, in terms of their surface chemical structure, morphology and properties using X-ray photoelectron spectroscopy, scanning electron microscopy, atomic force microscopy and contact angle measurements. The effect of the observed changes in terms of subsequent chitosan immobilization on plasma-treated films was also evaluated. The ability of native, plasma-treated and chitosan-coated films to support adhesion and growth of mesenchymal stem cells was studied to determine the practicability of this approach for the biomedical application of poly(ethylene terephthalate) films.

This research investigates the effect of plasma treatment with air, nitrogen (N2), and carbon dioxide (CO2) gases on the performance of waterborne (acrylic) and solvent-borne (polyester) coated fir (Abies alba M.) wood samples. The properties of the plasma-coated samples were analyzed before and after exposure to accelerated weathering and compared with those of untreated and solely treated ones. According to pull-off testing, the coating adhesion of the wood samples was considerably improved by plasma treatment, and obvious differences were observed between different plasma gases. The effect was more pronounced after the weathering test. Similar results were obtained for the abrasion resistance of the samples. The water contact angle measurement illustrated more hydrophilic character in the solely plasma-treated wood in comparison with the untreated wood. The application of coatings, however, strongly improved its hydrophobic character. The performances of waterborne and solvent-borne coatings on plasma-treated wood were comparable, although slightly better values were obtained by the waterborne system. Our results exhibit the positive effect of plasma treatment on coating performances and the increased weather resistance of the waterborne and solvent-borne coating systems on plasma-treated wood.

The purpose of this study was to evaluate the effect of non-thermal atmospheric pressure plasma (NTP) on shear bond strength (SBS) between yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) and self-adhesive resin cement. For this study, surface energy (SE) was calculated with cube-shaped Y-TZP specimens, and SBS was measured on disc-shaped Y-TZP specimens bonded with G-CEM LinkAce or RelyX U200 resin cylinder. The Y-TZP specimens were classified into four groups according to the surface treatment as follows: Control (no surface treatment), NTP, Sb (Sandblasting), and Sb + NTP. The results showed that the SE was significantly higher in the NTP group than in the Control group (p &lt, 0.05). For the SBS test, in non-thermocycling, the NTP group of both self-adhesive resin cements showed significantly higher SBS than the Control group (p &lt, 0.05). However, regardless of the cement type in thermocycling, there was no significant increase in the SBS between the Control and NTP groups. Comparing the two cements, regardless of thermocycling, the NTP group of G-CEM LinkAce showed significantly higher SBS than that of RelyX U200 (p &lt, 0.05). Our study suggests that NTP increases the SE. Furthermore, NTP increases the initial SBS, which is higher when using G-CEM LinkAce than when using RelyX U200.

Surface wettability plays an important role in determining the function of a wound dressing. Dressings with hydrophobic surfaces are suitable for bacterial adsorption, however, a hydrophilic surface is needed to improve cell attachment for most anchorage-dependent cell types. Furthermore, the hydrophobicity/hydrophilicity of the surface can be used to direct cellular processes such as cell initial attachment, adhesion, and migration during wound healing. Thus, a surface with an ability to switch their surface wettability improves the practicality of the dressing. In this study, we propose a temporary surface wettability tuning for surface patterning utilizing plasma treatment. Polycaprolactone (PCL) and polydimethylsiloxane (PDMS) surfaces were treated with tetrafluoromethane (CF4), sulphur hexafluoride (SF6), and oxygen (O2) plasma, and the effects on the surface wettability, roughness, and chemical composition were investigated. Based on the contact angle measurement, CF4 plasma altered surface wettability of PCL and PDMS films to hydrophobic and hydrophilic, respectively. After CF4 treatment, better attachment of primary mouse embryonic fibroblast cell (3T3) was observed on the treated PDMS surface. Embedding PCL into PDMS generated a hydrophobic-hydrophilic pattern mixture surface, which offers great potential in the tissue engineering field such as cell patterning and guidance.

The goal of this research was to examine the effect of two surface modification methods, i.e., radiation cross-linking and plasma treatment, on the adhesive properties and the final quality of adhesive bonds of polypropylene (PP), which was chosen as the representative of the polyolefin group. Polymer cross-linking was induced by beta (accelerated electrons&mdash, &beta, &minus, ) radiation in the following dosages: 33, 66, and 99 kGy. In order to determine the usability of &beta, radiation for these applications (improving the adhesive properties and adhesiveness of surface layers), the obtained results were compared with values measured on surfaces treated by cold atmospheric-pressure plasma with outputs 2.4, 4, and 8 W. The effects of both methods were compared by several parameters, namely wetting contact angles, free surface energy, and overall strength of adhesive bonds. Furthermore, Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) were conducted. According to our findings the following conclusion was reached, both tested surface modification methods significantly altered the properties of the specimen&rsquo, s surface layer, which led to improved wetting, free surface energy, and bond adhesion. Following the &beta, radiation, the free surface energy of PP rose by 80%, while the strength of the bond grew in some cases by 290% in comparison with the non-treated surface. These results show that when compared with cold plasma treatment the beta radiation appears to be an effective tool capable of improving the adhesive properties and adhesiveness of PP surface layers.

Wrinkles attract significant attention due to their ability to enhance the mechanical and optical characteristics of various optoelectronic devices. We report the effect of the plasma gas type, power, flow rate, and treatment time on the wrinkle features. When an optical adhesive was treated using a low-pressure plasma of oxygen, argon, and nitrogen, the oxygen and argon plasma generated wrinkles with the lowest and highest wavelengths, respectively. The increase in the power of the nitrogen and oxygen plasma increased the wavelengths and heights of the wrinkles; however, the increase in the power of the argon plasma increased the wavelengths and decreased the heights of the wrinkles. Argon molecules are heavier and smaller than nitrogen and oxygen molecules that have similar weights and sizes; moreover, the argon plasma comprises positive ions while the oxygen and nitrogen plasma comprise negative ions. This resulted in differences in the wrinkle features. It was concluded that a combination of different plasma gases could achieve exclusive control over either the wavelength or the height and allow a thorough analysis of the correlation between the wrinkle features and the characteristics of the electronic devices.

In this article, we present a development of atmospheric pressure plasma jets (APPJs) for modification of liquid solutions. APPJs were fabricated in low temperature cofired ceramics (LTCC) technology. During the measurements, plasma jets worked under various flowing gases, which can be used to produce plasma activated water. In addition, owing to the plasma treatment, it was possible to decrease the time of a synthesis of gold nanoparticles (AuNPs) without the use of additional hazardous reagents. The mechanism of gold nanoparticles formation in cold nitrogen plasma is also presented.

A commercial formulation of poly(tetrafluoroethylene) (PTFE) sheets were surface modified by using non-thermal air at 40 kHz frequency (DC) and 13.56 MHz radiofrequency (RF) at different durations and powers. In order to assess possible changes of PTFE surface properties, zeta potential (&zeta, ), isoelectric points (IEPs) determinations, contact angle measurements as well as Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) imaging were carried out throughout the experimentation. The overall outcome indicated that &zeta, potential and surface energy progressively changed after each treatment, the IEP shifting to lower pH values and the implicit differences, which are produced after each distinct treatment, giving new surface topographies and chemistry. The present approach might serve as a feasible and promising method to alter the surface properties of poly(tetrafluoroethylene).

The use of plastics has spanned across almost all aspects of day to day life. Although their uses are invaluable, they contribute to the generation of a lot of waste products that end up in the environment and end up polluting natural habitats such as forests and the ocean. By treating low-density polyethylene (LDPE) samples with non-thermal plasma in ambient air and with an addition of &asymp, 4% CO2, the biodegradation of the samples can be increased due to an increase in oxidative species causing better cell adhesion and acceptance on the polymer sample surface. It was, however, found that the use of this slight addition of CO2 aided in the biodegradation of the LDPE samples more than with solely ambient air as the carbon bonds measured from Raman spectroscopy were seen to decrease even more with this change in gas composition and chemistry. The results show that the largest increase of polymer degradation occurs when a voltage of 32 kV is applied over 300 s and with a mixture of ambient air and CO2 in the ratio 25:1.

This study reports the interactions of modified nanodiamond particles in vitro with human blood. Modifications performed on the nanodiamond particles include oxygenation with a chemical method and hydrogenation upon chemical vapor deposition (CVD) plasma treatment. Such nanodiamonds were later incubated in whole human blood for different time intervals, ranging from 5 min to 5 h. The morphology of red blood cells was assessed along with spectral measurements and determination of haemolysis. The results showed that no more than 3% of cells were affected by the nanodiamonds. Specific modifications of the nanodiamonds give us the possibility to obtain nanoparticles which are biocompatible with human blood. They can form a basis for the development of nanoscale biomarkers and parts of sensing systems and devices useful in biomedical environments.

Cell colonization of synthetic polymers can be regulated by physical and chemical modifications of the polymer surface. High-density and low-density polyethylene (HDPE and LDPE) were therefore activated with Ar⁺ plasma and grafted with fibronectin (Fn) or bovine serum albumin (BSA). The water drop contact angle usually decreased on the plasma-treated samples, due to the formation of oxidized groups, and this decrease was inversely related to the plasma exposure time (50-300 s). The presence of nitrogen and sulfur on the polymer surface, revealed by X-ray photoelectron spectroscopy (XPS), and also by immunofluorescence staining, showed that Fn and BSA were bound to this surface, particularly to HDPE. Plasma modification and grafting with Fn and BSA increased the nanoscale surface roughness of the polymer. This was mainly manifested on HDPE. Plasma treatment and grafting with Fn or BSA improved the adhesion and growth of vascular smooth muscle cells in a serum-supplemented medium. The final cell population densities on day 6 after seeding were on an average higher on LDPE than on HDPE. In a serum-free medium, BSA grafted to the polymer surface hampered cell adhesion. Thus, the cell behavior on polyethylene can be modulated by its type, intensity of plasma modification, grafting with biomolecules, and composition of the culture medium.

Cotton fabrics are highly popular because of their excellent properties such as regeneration, bio-degradation, softness, affinity to skin and hygroscopic properties. When in contact with the human body, cotton fabrics offer an ideal environment for microbial growth due to their ability to retain oxygen, moisture and warmth, as well as nutrients from spillages and body sweat. Therefore, an anti-microbial coating formulation (Microfresh and Microban together with zinc oxide as catalyst) was developed for cotton fabrics to improve treatment effectiveness. In addition, plasma technology was employed in the study which roughened the surface of the materials, improving the loading of zinc oxides on the surface. In this study, the low stress mechanical properties of plasma pre-treated and/or anti-microbial-treated cotton fabric were studied. The overall results show that the specimens had improved bending properties when zinc oxides were added in the anti-microbial coating recipe. Also, without plasma pre-treatment, anti-microbial-treatment of cotton fabric had a positive effect only on tensile resilience, shear stress at 0.5° and compressional energy, while plasma-treated specimens had better overall tensile properties even after anti-microbial treatment.

In the present work, we described the post-treatment effects of applying different plasma atmosphere conditions on the electrochemical performances of the multiwalled carbon nanotubes (MWCNTs). For the study, a composite of MWCNTs/Co/Ti was successfully grown on the silicon substrate and then pre-treated with ammonia, oxygen and hydrogen plasma. The composite was characterized by making use of field emission scanning electron microscopy (FESEM) for the surface morphology and Raman spectroscopy for the functionalization. Further, the electrochemical measurements were performed with the use of the cyclic voltammetry (CV) applied in the 0.01 M potassium ferricyanide in 0.1 M KCl solution. On testing, the results indicated that the NH3-treated MWCNTs have the highest efficiency as compared to the other pretreatments and control. This increased performance of NH3 treated sample can be linked to the enhanced surface area of the composite, thereby improved adsorption and associated interaction with that of the analyte molecules at the electrodes. Further comparison of the electrode with that of commercial Dropsens electrodes provided the confirmation for the efficiency of the NH3/MWCNTs, thereby suggesting for the potentiality of applying the NH3 modified electrode towards electrochemical applications.

In this work, amorphous indium-gallium-zinc oxide thin-film transistors (a-IGZO TFTs) with a HfO2 gate insulator and CF4 plasma treatment was demonstrated for the first time. Through the plasma treatment, both the electrical performance and reliability of the a-IGZO TFT with HfO2 gate dielectric were improved. The carrier mobility significantly increased by 80.8%, from 30.2 cm2/V∙s (without treatment) to 54.6 cm2/V∙s (with CF4 plasma treatment), which is due to the incorporated fluorine not only providing an extra electron to the IGZO, but also passivating the interface trap density. In addition, the reliability of the a-IGZO TFT with HfO2 gate dielectric has also been improved by the CF4 plasma treatment. By applying the CF4 plasma treatment to the a-IGZO TFT, the hysteresis effect of the device has been improved and the device’s immunity against moisture from the ambient atmosphere has been enhanced. It is believed that the CF4 plasma treatment not only significantly improves the electrical performance of a-IGZO TFT with HfO2 gate dielectric, but also enhances the device’s reliability.

Metacomposites, composite materials exhibiting negative permittivity, represent an opportunity to create materials with depressed plasmon frequency without the need to create complex structural geometries. Although many reports exist on the synthesis and characterizations of metacomposites, very few have ventured into exploring possible applications that could take advantage of the unique electrical properties of these materials. In this article, we report on the chemiresistive properties of a polymer-CNT metacomposite and explore how these are affected by Argon plasma treatment.

H2S plasma created by an electrode-less radio-frequency discharge was used to modify the surface properties of the polymer polyethylene terephthalate. X-ray photoelectron spectroscopy, secondary ion mass spectrometry and atomic force microscopy were used to determine the evolution of the surface functionalities and morphology. A very thin film of chemically bonded sulfur formed on the surface within the first 10 s of treatment, whereas treatment for more than 20 s caused deposition of higher quantities of unbonded sulfur. The sulfur concentration reached a maximum of between 40 and 80 s of plasma treatment; at longer treatment times, the unbonded sulfur vanished, indicating instability of the deposited sulfur layer. Large differences in the surface morphology were observed.

Surfaces of carbon fibre roving were modified by means of a low temperature plasma treatment to improve their bonding with mineral fines; the latter serving as an inorganic fibre coating for the improved mechanical performance of carbon reinforcement in concrete matrices. Variation of the plasma conditions, such as gas composition and treatment time, was accomplished to establish polar groups on the carbon fibres prior to contact with the suspension of mineral particles in water. Subsequently, the rovings were implemented in a fine concrete matrix and their pull-out performance was assessed. Every plasma treatment resulted in increased pull-out forces in comparison to the reference samples without plasma treatment, indicating a better bonding between the mineral coating material and the carbon fibres. Significant differences were found, depending on gas composition and treatment time. Microscopic investigations showed that the samples with the highest pull-out force exhibited carbon fibre surfaces with the largest areas of hydration products grown on them. Additionally, the coating material ingresses into the multifilament roving in these specimens, leading to better force transfer between individual carbon filaments and between the entire roving and surrounding matrix, thus explaining the superior mechanical performance of the specimens containing appropriately plasma-treated carbon roving.