Vacuum Plasma Treatment Research Articles

Osseointegration of Dental Implants after Vacuum Plasma Surface Treatment In Vivo.

Previous studies have highlighted the need for post-treatment of implants due to surface aging. This study investigated the effect of vacuum plasma (VP) treatment on the osseointegration of sandblasted, large grit, acid-etched (SLA) implant surfaces. The hypothesis was that VP might enhance implant stability, measured by implant stability quotient (ISQ) and histological osseointegration through bone-to-implant contact (BIC) and bone area ratio (BA) in rabbit models. Eighteen implants were either untreated or treated with VP and installed into the femurs of six rabbits, which were sacrificed after four weeks. Histological analyses of BIC and BA, along with micro-CT analysis of bone volume and ISQ, were performed. The VP-treated group showed higher levels of BA, bone volume, and ISQ, but no statistically significant differences were observed between the control and experimental groups. Despite limitations, both groups achieved better osseointegration and regeneration, warranting further studies on plasma treatment effects over varying implantation periods.

Surface treatment of artificial implants with hybrid nanolayers: results of antibacterial tests, leachates and scanning electron microscope analysis.

The aim of this study was to evaluate the antibacterial efficacy of surface-treated hernia implants modified by a hybrid nanolayer with incorporated Ag, Cu, and Zn cations using the sol-gel method. The materials (polypropylene, polyester, and polyvinylidene difluoride) were activated by vacuum plasma treatment or UV C radiation, then modified and tested for bacterial strains of Escherichia coli (gram-negative) and Staphylococcus aureus (gram-positive). The AATCC 100 (2019) method for quantitative and the ISO 20645 agar plate propagation method for qualitative evaluation of microbiological efficacy were used. The gradual release of incorporated ions was monitored over time in simulated body fluids (blood plasma, peritoneal fluid) and physiological saline using an inductively coupled plasma mass spectrometer. The thickness and the homogeneity of the layers were measured for individual random samples with scanning electron microscope analysis (SEMA) and evaluated with an elemental analysis. Qualitative and quantitative microbiological tests clearly show the great suitability of vacuum plasma and UV C with sol AD30 (dilution 1:1) surface treatment of the implants. The absolute concentration of Ag, Cu, and Zn cations in leachates was very low. SEMA showed a high degree of homogeneity of the layer and only very rare nanocracks by all tested materials appear after mechanical stress. This study confirms that surface treatment of meshes using the sol-gel method significantly increases the antibacterial properties. The nanolayers are sufficiently mechanically resistant and stable and pose no threat to health.

Improvement in Biocompatibility and Biointegration of Human Acellular Dermal Matrix through Vacuum Plasma Surface Treatment.

Efforts are ongoing to enhance the functionality of human acellular dermal matrices (hADMs), which are extensively utilized in reconstructive surgeries. Among these efforts, plasma treatments, particularly vacuum plasma treatments, have recently emerged in the medical field. This study aims to investigate the efficacy of a vacuum plasma treatment in enhancing the biocompatibility and biointegration of hADMs. Utilizing a plasma activator (ACTILINK reborn, Plasmapp Co., Ltd., Daejeon, Republic of Korea), hADMs were treated and evaluated through in vitro and in vivo analyses. Hydrophilicity changes were gauged by the blood absorption times, while SEM imaging was used to analyze physical surface deformation. Protein adsorption was measured with fluorescently labeled bovine serum albumin and fibronectin. For the in vivo study, mice were implanted with plasma-treated and untreated hADMs, and the post-implantation effects were analyzed through histological and immunofluorescence microscopy. The plasma-treated hADMs demonstrated a significantly enhanced hydrophilicity compared to the untreated samples. SEM imaging confirmed the maintenance of the microroughness after the treatment. The treated hADMs showed a significant reduction in fibronectin adsorption, a critical factor for cellular adhesion. In vivo, the plasma-treated hADMs exhibited reduced capsule formation and enhanced fibroblast infiltration, indicating improved biocompatibility and integration. These findings highlight the potential of a plasma treatment to enhance the performance of hADMs in clinical settings, offering a promising avenue for improving reconstructive surgery outcomes.

Vacuum Plasma Treatment Device for Enhancing Fibroblast Activity on Machined and Rough Titanium Surfaces.

This study was conducted to compare the effects of an innovative plasma surface treatment device that does not need a gas supply for titanium disks with two different surface topographies: the prototypical machined surface (MAC) and one of the most diffused roughened ones (SL) obtained through grit blasting and acid etching. A total of 200-MAC and 200-SL titanium disks were used. Each group of disks was divided into four sub-groups of 40 samples each that were subjected to five different tests. Among these, 150-MAC and 150-SL were considered the test group, and they were treated with plasma for 15, 30, and 60 s after being removed from the sterile packaging. On the other hand, 50-MAC and 50-SL were considered the control group, and they were only removed from sterile plastic vials. The samples were analyzed to evaluate the capability of the plasma treatment in influencing protein adsorption, cell adhesion, proliferation, and microbial growth on the test group disks when compared to the untreated disks. Protein adsorption was significantly enhanced after 20 min of plasma treatment for 15 and 30 s on the MAC and SL disks. Plasma treatment for 15 and 30 s significantly increased the level of adhesion in both treated samples after 30 min. Furthermore, the MAC samples showed a significant increase in cell adhesion 4 h after plasma treatment for 15 s. The SEM analysis highlighted that, on the treated samples (especially on the MAC disks), the cells with a polygonal and flat shape prevailed, while the fusiform- and globular-shaped cells were rare. The encouraging results obtained further confirm the effectiveness of plasma treatments on cell adhesion and fibroblast activity.

Selective Surface Treatment Using Atmospheric Ar Plasma Jet for Aluminum‐doped Zinc Oxide Based Transparent and Flexible Electronics

AbstractTransparent and flexible electronics are emerging technologies with the potential to enable new applications. However, to ensure high‐performance transparent electronics, post‐processing such as thermal annealing and vacuum plasma treatment is necessary, which are difficult to apply to polymer‐based flexible substrates. This study analyzed the feasibility of applying selective Ar plasma jet treatment at atmospheric pressure to transparent flexible electronics. When atmospheric Ar plasma treatment is applied to transparent flexible aluminum‐doped zinc oxide (AZO), it showed a maximum 83.1% improvement in sheet resistance while maintaining a high transmittance performance, of over 70%. To verify the mechanism behind the surface treatment effect using atmospheric Ar plasma, comprehensive analyses are performed using atomic force microscopy, X‐ray diffraction, and X‐ray photoelectron spectroscopy, which confirmed that the effect is due to oxygen vacancy formation caused by ion bombardment and thermal diffusion. The application of atmospheric plasma treatment to a patterned transparent flexible AZO device resulted in a reduction in contact resistance, and it is confirmed that the performance improvement effects can be retained for >500 h by applying additional passivation.

Structure and Properties of Black Ceramic MAO Coatings on Aluminum Alloys

The existing processes for obtaining black wear-resistant coatings include chemical methods, anodic oxidation followed by painting in aniline dyes, electrochemical deposition, vacuum plasma treatment, microarc oxidation (MAO). Of great interest for the formation of light-absorbing coatings is the MAO method, which is characterized as a reliable and environmentally friendly process, which provides the formation of a hard ceramic-like oxide layer with high corrosion resistance аnd good adhesion to the substrate. Therefore, the development of methods for obtaining high-quality black MAO coatings with both high optical and mechanical characteristics is currently an urgent task. The paper presents the results of a study of the structure and properties of black ceramic coatings on aluminum alloy AMg2 obtained by microarc oxidation using silicate-alkaline and silicate-phosphate electrolytes containing potassium ferrocyanide and sodium tungstate as coloring components. Sodium tungsten acid and potassium ferrocyanide with a concentration of 0.5 to 2.0 g/l were added to the electrolytes as additional components that ensured the coloring of the coatings. It has been established that the most saturated black coatings in a silicate-alkaline electrolyte are formed with the addition of 1.5–2.0 g/l of sodium tungstate, and in a silicate-phosphate electrolyte with the addition of 1.5 g/l of potassium ferrocyanide. The use of an electrolyte containing sodium tungstate makes it possible to form coatings with a lower microroughness height (Ra 0.97–1.11 µm) compared to coatings obtained in an electrolyte containing potassium ferrocyanide (Ra up to 4.20 µm). The maximum wear resistance of the resulting coatings (wear rate (0.38–0.59) × 10–4 mm3/(m×N)) is achieved by treatment in the studied electrolytes with a duration of 10 min. In this case, the thickness of the coatings is 21–31 µm. A further increase in the duration of processing does not have a significant effect on the wear rate.

Investigation and feed‐forward neural network‐based estimation of dyeing properties of air plasma treated wool fabric dyed with natural dye obtained from Hibiscus sabdariffa

AbstractIn the colouring processes of textile products, more environmentally friendly chemicals and finishing methods should be used instead of conventional ones that harm the environment every day, so that alternative realistic ways to protect nature, both academically and industrially, could be possible. Due to some inconveniences caused by synthetic dyes that are widely used today, in this study, ultrasonic dyeing of wool fabric with Hibiscus sabdariffa was carried out after environmental‐friendly air vacuum plasma application which increased the absorption of the dyes into the textile material. According to the performance results, colour strengths of the wool fabrics were increased significantly. Surface morphology analysis was carried out and etching effects of air vacuum plasma treatment were clearly seen on the micrographs of the treated wool fabrics. An environmental‐friendly green process was achieved through this study and it was concluded that vacuum air plasma treatment could be an alternative green‐process as a pretreatment to increase the dye up‐take of natural dyeing treatment. Moreover, in this study, a feed‐forward neural network (FFNN) model was presented and used for predicting the dyeing properties (L, a, b and K/S) of samples. The experimental results showed that the presented model achieves the regression values greater than 0.9 for all dyeing properties. Consequently, it was considered that the proposed FFNN was successfully modelled and could be efficiently utilised for dyeing characteristics of wool fabrics dyed with natural dye extracted from Hibiscus sabdariffa.

Vacuum plasma treatment on carbon nanoparticles for highly sensitive square wave voltammetric sensor of heavy metal ions

Heavy metal ions are dangerous pollutants since they are non-biodegradable and accumulate in ecological systems. The identification of these ions is extremely important in environmental quality monitoring. However, despite the importance of detecting heavy metals, research on sensor electrode materials for sensing them is still insufficient. In the present study, we suggest functional group introduced carbon nanoparticles (CNPs) using a simple vacuum plasma process. Polypyrrole nanoparticles (PPyNPs) are used as carbon precursors to produce CNPs and various functional groups are introduced following exposure with different gases (NH3, C4F8, and O2) during the vacuum plasma process. Plasma-treated CNPs show fast charge transfer and high sensitivity to the heavy metal ions (Pb2+ and Cu2+). Particularly, O2 gas-treated CNPs (O-CNPs) possess an excellent sensing ability as compared to the other treated CNPs. Under optimized conditions, O-CNPs show a limit of detection (LOD) of 0.005 μM for Pb2+ and 0.01 μM for Cu2+. O-CNPs also show a linearity for the detection signal of metal ions over a wide concentration range (0.01–100 μM for Pb2+ and 0.1–100 μM for Cu2+).

Oxygen Gas Vacuum Plasma Treatment on PVA/Chitosan/HAp Scaffold Nanofiber

Oxygen Gas Vacuum Plasma Treatment on PVA/Chitosan/HAp Scaffold Nanofiber

Linear and non-linear optical properties of boron carbide thin films

Boron carbide films deposited by PECVD are subjected to post deposition vacuum annealing and plasma treatment for investigation of changes in the structure, linear and non-linear optical properties of the films. Deconvolution of core level XPES spectra of B1s, C1s and O1s indicates changes in the surface chemical states of the constituent atoms after post deposition treatments. Particle size estimated from XRD spectrum is found increasing from 135 to 140 nm after annealing. Envelop method is used to estimate refractive index, extinction co-efficient, and thickness from their measured optical transmission spectra in VIS-NIR region (400–1400 nm). The refractive index value is found to be 1.619, highest for the vacuum annealed boron carbide film. Direct and indirect optical bandgap remains same after vacuum annealing (Eg = 2.84), the plasma treatment causes a slight decrease in the bandgap. 5% decrease in film thickness is observed after post deposition annealing and plasma treatment owing to film densification. Energy loss in the medium measured in terms of tanδ and ELF’s reveals that the vacuum annealing of the film reduces the electromagnetic and electron energy loss in the film. Non-linear refractive index estimated using Ticha and Tichy relation exhibits similar trend as the linear refractive index spectra.

Plasma-assisted seconds-level-impregnated preparation of bifunctional N-doped NiCoP with O vacancies enhancement: Driving efficient water splitting

Improving water splitting efficiency of low-cost catalysts is one key to promoting energy-efficient and environmentally friendly hydrogen production. Herein, we propose a rational strategy to construct cross-linked N-doped NiCoP nanostructure with elevated catalytic active sites. The O vacancies from two sources of vacuum annealing and plasma treatment can not only facilitate M−P binding but also enable in situ doping of N atoms, thus benefiting the capture of protons. Density function theory (DFT) calculation further reveals that N doping can play a key role in modulating the electronic structure and lowering the reaction barriers. As expected, the optimized N-NiCoP-ov11 requires a cell voltage of 1.53 V to deliver 10 mA cm−2 current density for overall water splitting with satisfactory stability. This work provides a feasible strategy to combine efficient catalysis and low cost for overall water splitting.

Investigation and Optimization of Vacuum Plasma Treatment of PA66 Fabric for Reduced Fire Retardant Consumption.

Flame retardant (FR) textiles were obtained by surface treatments of polyamide 66 fabrics with microwave (MW) plasma technology in order to reduce the amount of FR involved in the fabric finishing process. More specifically, MW vacuum plasma was employed for polymer surface activation by using a helium/oxygen (He/O2) gas mixture, evaluating the effect of different treatment parameters on the affinity toward thiourea impregnation. Surface fabric modification was investigated both in terms of uniformity and increased thiourea absorption by infrared spectroscopy, wicking properties, and gravimetric characterization to define an operative window for plasma treatment conditions. According to the results obtained, the dry add-on content of thiourea improved up to 38%, thanks to the increase of the fabric surface activation. The effectiveness of plasma treatment resulted in an absolute increase up to 2% in limiting oxygen index (LOI) performance with respect to untreated fabric. As a consequence, a drastic reduction of 50% in thiourea concentration was required to achieve a similar fire retardant performance for plasma-treated fabric. On the basis of these preliminary results, a design of experiment (DoE) methodology was applied to the selected parameters to build a suitable response surface, experimentally validated, and to identify optimized treatment conditions. At the end, a final LOI index up to 43% has been reached.

Ultra‐High Fluorine Enhanced Homogeneous Nucleation of Lithium Metal on Stepped Carbon Nanosheets with Abundant Edge Sites

AbstractDisordered nucleation sites and a fragile solid electrolyte interphase on the reactive interface tend to cause uncontrolled growth of lithium dendrites, which induce severe safety concerns and prevent lithium metal batteries from finding practical applications. Herein, novel stepped carbon nanosheets with abundant step edges and ultra‐high fluorine content (37.44 at%) are fabricated by combining an improved molten salt synthesis method with C4F8 vacuum plasma treatment. The solvent‐induced spatial confinement effect, i.e., orientation carbonization of pitch macromolecules, leads to the formation of step‐edge‐enriched nanoarrays. Meanwhile, the adequate exposure of edge sites on the basal plane of carbon nanosheets is conducive to achieve the ultra‐efficient doping of elemental fluorine in only 10 min. Further experiments and theoretical calculations demonstrate that the coupling effect of sufficient edge sites and active semi‐ionic CF/covalent CF2 groups on the carbon surface can not only form 2D fluorinated lithium chain and a robust LiF network, but also effectively facilitate Li ion redox kinetics and morphological stability, presenting a step‐edge‐guided plating process. As such, the developed anodes deliver an ultra‐low nucleation overpotential (≈10.5 mV), high Coulombic efficiency (>98% over 385 cycles), ultra‐long cycling duration for up to 3000 h under ≈10 mV, and excellent full battery performance.

Algorithm of electrode material selection during electrical erosion alloying

Purpose. The purpose is improving the quality of the surface layer of new and renewable machine parts by doping. Development of an algorithm for selecting electrode material for electric-spark doping of parts based on the method of successive approximation. Research methods were based on existing technological methods and equipment that allow the process of electric-spark doping to be carried out with a given thickness of the surface layer of the part. The following factors are used as controlling factors in creating such a layer: the electric processing mode, the chemical elements introduced into the composition of the doped layer, and their percentage, as well as the technological processing scheme (disposable or reusable). Research results. The method of electrical erosion alloying doping in its advantages surpasses such methods of restoring worn surfaces of parts such as detonation-gas and vacuum-plasma treatment, surfacing, electroplating, metallization by sputtering. Special equipment allows to carry out electric-spark doping with any given continuity of the surface layer and to increase the productivity of the process. When electrical erosion alloying is doping with an electrode containing refractory elements and their compounds, the conditions preventing the setting of the first and second kinds are fulfilled, since doping with these elements raises the melting point of the starting material, and the formation of a threedimensional cellular substructure promotes an increase in the creep temperature. Scientific novelty. For the first time, a rational algorithm is proposed for selecting electrode material based on the method of successive approximation. After a series of successive approximations, stabilization of the phase composition of the system is achieved and the chemical composition of the electrode is refined with the required ratio of the type of carbides and intermetallic compounds. Practical value. The use of electrical erosion alloying doping in the restoration of parts will provide an increase in wear resistance and heat resistance of the processed surfaces by 1,5–2 times in industry. As a result of electrical erosion alloying doping with the most common electrodes of the type VK and TK, conditions that prevent the occurrence of abrasive wear and seizure are automatically fulfilled.

Fluorination of shape-controlled porous carbon nanoweb layers for ammonia gas sensor applications

Fluorinated porous carbon nanoweb layers (FPCNWLs) are simply fabricated by spin coating of adjusting polymer mixing ratio, sequential thermal treatments, and vacuum plasma treatment to enhance the specific surface area and to dope the fluorine into the carbon lattice. The different surface tension, polarity, and molecular weight of PAN and PS causes immiscible solution, therefore, the various size of pores on the carbon structure are constructed during the stepwise thermal treatment. Moreover, the F doping ratio is easily controlled with different plasma treating time. The fluorination causes both p-type doping and affinity toward ammonia gas. The fabricated FPCNWLs-based ammonia gas sensor devices demonstrate outstanding NH3 gas sensing performances that minimum detection level (MDL) of FPCNWLs-based ammonia gas sensor is 9 ppb using FPCNWL20 and the sensors display linear range from 9 ppb to 90 ppm. In conclusion, the FPCNWL20-based ammonia gas sensor demonstrates rapid response and recovery time, excellent cyclic stability, reusability, durability, and selectivity.

Adhesion enhancement of conductive graphene/PI substrates through a vacuum plasma system

Flexible electronics is regarded as a promising solution to stretchable/wearable devices given its light weight and high deformation ability. As a conducting layer, a widely utilized transparent conducting film, namely, indium tin oxide (ITO), is approaching its limitation on flexible applications given its high stiffness and brittle characteristics. Thus, this study proposes a highly flexible bi-layered architecture composed of polyimide (PI) substrate and coated graphene ink. This architecture is considered to replace the foregoing ITO film. A vacuum plasma system with different treatment parameters is taken into account to enhance the interfacial adhesion of graphene/PI substrates. Furthermore, a fracture-based finite element model of patterned graphene/PI substrates with various line widths are constructed to ensure the applicability of the presented stacked structure to actual flexible applications. This model aims to analyze the interfacial cracking energy under several designed bending radii of curvature through a modified virtual crack closure technique. To determine the fractured criterion of graphene/PI interfacial adhesion, a series of pull-off and lap shear tests are performed while requiring a comparison with simulated predictions. Results show that the peeling mode dominates the interfacial delamination of graphene/PI substrates, and the critical pull-off energy is appropriated to judge the fractured occurrence in accordance with the corresponding results of experimental bending tests. The adoption of vacuum plasma treatment contributes to enhancing the interfacial adhesion of the concerned interface and preventing the delamination failure occurrence during operating flexural loads.

Accelerated construction of an in vitro model of human periodontal ligament tissue: vacuum plasma combined with fibronectin coating and a polydimethylsiloxane matrix.

Tying shape memory wires to crowded teeth causes the wires to deform according to the dental arch. This deformation results in a resilient force that is delivered to the tooth. The appropriate amount of force can activate the osteogenetic and osteoclastic ability of the periodontal ligament (PDL) and the tooth can be moved. This is the biological basis of orthodontic treatment. To achieve further insight into the mechanisms underlying orthodontic treatment, we examined whether accelerated construction of an in vitro human PDL fibroblast (HPdLF) stretching model can be achieved by combining fibronectin coating and vacuum plasma treatment with polydimethylsiloxane (PDMS) cell-culture chambers. Each chamber was randomly assigned to a no-surface modification (NN), fibronectin coating (FN), vacuum plasma treatment (PN), or vacuum plasma treatment followed by a fibronectin coating (PF) treatment protocol. The physical and chemical features and ability to promote cellular proliferation of the PDMS chamber surfaces were evaluated. Cellular adhesion of four materials were evaluated and two best-proliferated groups were considered as better model-constructing surfaces and used in subsequent experiments and used in subsequent experiments. HPdLFs were cultured on these two kinds of chambers without stretching for 3 days, then with stretching for 7 days. Time-course gene expression cellular morphology were evaluated. Chambers in the PN group had high wettability and surface component changes. The FN and PF chambers had high cellular proliferation ability. They were selected into subsequent experiments. After 3 days of culturing HPdLFs on the PF and PN chambers, the cells in the PF chambers had significantly higher levels of runt-related transcription factor 2 (Runx-2) and osteocalcin (OCN) gene expression compared with the cells in the PN chambers. After cyclic stretch application to the cells in the PN and PF chambers, expression of the type-3 collagen (COL-3) gene in PF group continued to increase for 7 days and was significantly higher than that in the PN group from day 5 onwards. The HPdLFs in the PF group showed parallel alignment from days 3 to 7 after imposition of cyclic stretch, while those in the PN group aligned in parallel from day 5 on. Our results suggested that applying a fibronectin coating to a PDMS chamber after plasma treatment can accelerate establishment of an in vitro PDL stretching model.

Effect of process gases in vacuum plasma treatment on adhesion properties of titanium alloy substrates

The subject of this paper is the quantitative evaluation of the correlation which exists between the surface characteristics of parts in a titanium alloy, Ti-6Al-4V, and the mechanical strength of the joints, made linking these parts using a structural epoxy adhesive. In particular, the surfaces were prepared by using vacuum plasma as a prebonding treatment with various process gases (air, Ar and O2). For each of these treatments, tests were performed for the mechanical characterisation of the joints, and surveys on the wettability properties were carried out by using a sessile drop method in order to estimate the surface energy of plasma treated surfaces. The results were related to the morphological and electrical properties of the substrates, defined in parallel through SKPM assessment. Further XPS analyses of their chemical state allowed the evaluation of the effect of vacuum plasma on both contaminant removal and formation of a weak oxide layer. The results obtained highlighted interesting relationships between vacuum plasma surface preparation and mechanical resistance of the bonded joints, as well as synergy between the morphological, electrical and chemical properties present in adhesive phenomena.

The influence of duplex vacuum-plasma treatment on the mechanics of complex-profile cutting tool wearing in the production of aircraft engine parts

The paper presents a series of experimental results for assessing the effect of duplex vacuum-plasma processing as sequential ion nitriding and coating (Nb–Ti–Al–V) N on the characteristics of the surface layer and the wear rate of complex profile tools as herringbone broaches and gear-shaping cutters from high-speed steels powder during machining a heat-resistant nickel-based alloy. The rational duplex processing modes for each type of multi-profile cutting tool under investigation were established. Tests of the tool after duplex processing under conditions close to those encountered in production showed an increase in the operational durability of herringbone broaches and gear-shaping cutters up to two times in comparison with the original tool.

The properties of ZnO films obtained by high-frequency magnetron deposition with subsequent vacuum annealing and plasma treatment

The method of high-frequency magnetron sputtering allows to obtain thin films of zinc oxide with nanostructured surface morphology and, consequently, with unique optical characteristics. Such coating can provide an increase in the number of particles penetrating the photovoltaic structure and the length of their optical path. Vacuum-plasma processing of ZnO films allows to change the morphology of their surface, and annealing largely influences the optical transmission.