Use Of Plasma Treatment Research Articles

Bone-to-Implant Contact in Implants with Plasma-Treated Nanostructured Calcium-Incorporated Surface (XPEEDActive) Compared to Non-Plasma-Treated Implants (XPEED): A Human Histologic Study at 4 Weeks

Titanium implants undergo an aging process through surface hydrocarbon deposition, resulting in decreased wettability and bioactivity. Plasma treatment was shown to significantly reduce surface hydrocarbons, thus improving implant hydrophilicity and enhancing the osseointegration process. This study investigates the effect of plasma surface treatment on bone-to-implant contact (BIC) of implants presenting a nanostructured calcium-incorporated surface (XPEED®). Following a Randomized Controlled Trial (RCT) design, patients undergoing implant surgery in the posterior maxilla received additional plasma-treated (n = 7) or -untreated (n = 5) 3.5 × 8 mm implants that were retrieved after a 4-week healing period for histological examination. Histomorphometric analysis showed that plasma-treated implants exhibited a 38.7% BIC rate compared to 22.4% of untreated implants (p = 0.002), indicating enhanced osseointegration potential. Histological images also revealed increased bone formation and active osteoblastic activity around plasma-treated implants when compared to untreated specimens. The findings suggest that plasma treatment improves surface hydrophilicity and biological response, facilitating early bone formation around titanium implants. This study underscores the importance of surface modifications in optimizing implant integration and supports the use of plasma treatment to enhance osseointegration, thereby improving clinical outcomes in implant dentistry and offering benefits for immediate and early loading protocols, particularly in soft bone conditions.

Plasma treatment enhanced piezo-photocatalytic performance of Bi2WO6 for efficient degradation of tetracycline hydrochloride

Photocatalysis is limited by the high recombination rate of photogenerated e- and h+, but the piezoelectric effect can enhance the separation efficiency of charge carriers, so that the combining piezoelectric catalysis with photocatalysis is a highly promising approach for improving catalytic performance. In this study, aim to enhance piezo-photocatalytic performance, plasma treatment was applied to modify the surface of Bi2WO6 to form oxygen vacancies. After plasma treatment, Bi2WO6 exhibited a larger specific surface area, thinner thickness, narrower band gap, etc. These improvements have been confirmed to enhance the piezoelectric response of Bi2WO6, facilitate band bending and further improve the absorption of visible light, accelerate the separation of charge carriers, thus enhanced the piezo-photocatalytic activity. Consequently, utilization of plasma treatment had improved greatly the piezo-photocatalytic performance of Bi2WO6 for the degradation of tetracycline hydrochloride. Impressively, plasma treatment promoted the generation of 1O2 during the piezo-photocatalytic reaction, emphasizing the advantages of utilizing plasma treatment for improving the performance of piezo-photocatalysts. This work highlights the use of plasma treatment to increase active sites and induce vacancy defects on the surface of catalysts, which exhibit excellent piezo-photocatalytic degradation performance and show great potential in the field of environmental remediation.

Silane Effects on Adhesion Enhancement of 2K Polyurethane Adhesives.

With excellent properties such as great flexibility, outstanding chemical resistance, and superb mechanical strength, two-part polyurethane (2K PU) adhesives have been widely applied in many applications, including those in transportation and construction. Despite the extensive use, their adhesion to nonpolar polymer substrates still needs to be improved and has been widely studied. The incorporation of silane molecules and the use of plasma treatment on substrate surfaces are two popular methods to increase the adhesion of 2K PU adhesives, but their detailed adhesion enhancement mechanisms are still largely unknown. In this research, sum frequency generation (SFG) vibrational spectroscopy was used to probe the influence of added or coated silanes on the interfacial structure at the buried polypropylene (PP)/2K PU adhesive interface in situ. How plasma treatment on PP could improve adhesion was also investigated. To achieve maximum adhesion, two methods to involve silanes were studied. In the first method, silanes were directly mixed with the 2K PU adhesive before use. In the second method, silane molecules were spin-coated onto the PP substrate before the PU adhesive applied. It was found that the first method could not improve the 2K PU adhesion to PP, while the second method could substantially enhance such adhesion. SFG studies demonstrated that with the second method silane molecules chemically reacted at the interface to connect PP and 2K PU adhesive to improve the adhesion. With the first method, silane molecules could not effectively diffuse to the interface to enhance adhesion. In this research, plasma treatment was also found to be a useful method to improve the adhesion of the 2K PU adhesive to nonpolar polymer materials.

Enhancement of wheat yield by atmospheric pressure plasma treatment

The use of plasma treatment in agriculture has shown promising results in improving seed germination and crop production. In this work, we have investigated the effects of atmospheric pressure plasma treatment on wheat seed germination and production qualities. Dielectric barrier discharge and plasma-activated water (PAW) made by gliding discharge plasma have been used for the treatment. Our results show that plasma-treated wheat seeds have better germination rates and higher production qualities. Among the various treatment times tested, 3 min of direct plasma treatment yields the highest germination rates, and 15 min of PAW produces the best results. Furthermore, the wettability and contact angle of the seeds decreases significantly with increasing treatment time. Our findings suggest that the atmospheric pressure plasma treatment can enhance the germination rate of wheat seeds and their production, which has potential applications in agriculture.

Use of Plasma Treatment to Increase the Seam Strength of Protective Clothing Made of Composite Material

Use of Plasma Treatment to Increase the Seam Strength of Protective Clothing Made of Composite Material

Effects of plasma treatments of polypropylene adhesive joints used in the automotive industry

Plasma treatment has been used in recent years to activate the surfaces of adhesive substrates and thus as an adhesion promoter between adhesive and substrates. The use of plasma treatments is widely adopted in the automotive industries especially for polymers that present low surface energy, such as polypropylene. In this work, polypropylene substrates used in the automotive industries have been treated with two different techniques: vacuum and atmospheric plasma. Then, polyurethane and methacrylate adhesives have been used to bond single lap joints (SLJs). Typically, these two adhesives cannot bond polypropylene substrates without surface treatments. An experimental plan has been designed to investigate the process parameters that can increase the functional polar groups (FPGs) maximizing the adhesion strength. Besides the types of plasma, two different gas carriers (air and nitrogen) and different treatment times have been investigated. The substrates, treated and not treated, have been assessed through scanning electron microscopy, energy-dispersive X-ray analysis, and Fourier-transform infrared spectroscopy to quantitatively assess the increment of FPGs after the different treatments. The experimental plan shows that the atmospheric plasma can improve the surface of the substrates by using a smaller time. Mechanical tests on SLJs show that methacrylate and polyurethane cannot bond polypropylene substrates without the plasma treatment. On the other hand, the treated substrates can form a strong bonding with the adhesive since all SLJs exhibit a substrate failure. Mechanical tests have been also carried out after three different aging cycles showing that the adopted plasma treatment is not affected by the aging cycles.

Eco-friendly foam biocomposites based on cellulose extracted from date palm leaves and low-density polyethylene

The design of composite materials using environmentally compatible materials and adopting sustainable preparation techniques is very necessary for a better environment. The present study is a step towards developing an environmentally friendly alternative to foam-based composites. The aim of the study is to understand the effect of natural fibers from date palms on the property of foam biocomposites. We adopted an environmentally friendly method of compatibilization between the polymer and the fibers for better reinforcement. The compatibility was done by environmentally friendly physical modification using plasma treatment. Plasma treatment provides surface modification and is an economical solution for further processing. In fact, three types of interfaces have been created: (1) by the addition of maleic anhydride, (2) by the use of plasma-treated low-density polyethylene, (3) by the combination of maleic anhydride and plasma. The overall performance was best in the use of plasma treatment alone. The effect was carefully analyzed based on morphological, mechanical and thermal studies. Finally, a morphology–property correlation was established.

Novel plasma treatment for preparation of laser sintered nanocomposite parts

Polymer Laser Sintering (LS) is a well-known Additive Manufacturing process, capable of producing highly complex geometries with little or no cost penalty. However, the restricted range of materials currently available for this process has limited its applications. Whilst it is common to modify the properties of standard LS polymers with the inclusion of fillers e.g. nanoclays, achieving effective dispersions can be difficult. The work presented here investigates the use of plasma treatment as a method of enhancing dispersion with an expectation of improving consistency and surface quality of laser sintered nanocomposite parts. To enable the preparation of polyamide 12 nanocomposite powder for applications in LS, plasma surface modification using Low Pressure Air Plasma Treatment was carried out on two nanoclays: Cloisite 30B (C30B) and Nanomer I.34TCN (I.34TCN). Plasma treatment strongly reduced the aggregation of the nanoclay (C30B and I.34TCN) particles, and powders displayed higher decomposition temperatures than those without plasma treatment. LS parts from neat polyamide 12, untreated I.34TCN and plasma treated I.34TCN composites were successfully produced with different complex shapes. The presence of well dispersed plasma treated nanoclays was observed and found to be essential for an improved surface quality of LS fabricated which was achieved only for plasma treated I.34TCN. Likewise, some mechanical properties could be improved above that of PA12 by incorporation of treated I.34TCN. For example, the elastic modulus of plasma treated composites was higher than that of polyamide 12 and the untreated composite. In the case of the ultimate strain, the plasma treated composite performed better than untreated and results had a reduced variation between samples. This illustrates the feasibility of the use of plasma treatments on nanoclays to improve the properties of LS parts, even though further studies will be required to exploit the full potential.

Use of cold-atmospheric plasma in oncology: a concise systematic review.

Background:Cold-atmospheric plasma (CAP) is an ionized gas produced at an atmospheric pressure. The aim of this systematic review is to map the use of CAP in oncology and the implemented methodologies (cell targets, physical parameters, direct or indirect therapies).Methods:PubMed, the International Clinical Trials Registry Platform and Google Scholar were explored until 31 December 2017 for studies regarding the use of plasma treatment in oncology (in vitro, in vivo, clinical trials).Results:190 original articles were included. Plasma jets are the most-used production systems (72.1%). Helium alone was the most-used gas (35.8%), followed by air (26.3%) and argon (22.1%). Studies were mostly in vitro (94.7%) and concerned direct plasma treatments (84.2%). The most targeted cancer cell lines are human cell lines (87.4%), in particular, in brain cancer (16.3%).Conclusions:This study highlights the multiplicity of means of production and clinical applications of the CAP in oncology. While some devices may be used directly at the bedside, others open the way for the development of new pharmaceutical products that could be generated at an industrial scale. However, its clinical use strongly needs the development of standardized reliable protocols, to determine the more efficient type of plasma for each type of cancer, and its combination with conventional treatments.

Long‐term stable hydrophilic surface modification of poly(ether ether ketone) via the multilayered chemical grafting method

ABSTRACTThe aging phenomena of a poly(ether ether keton) (PEEK) surface hydrophilically modified via various protocols was investigated. The use of plasma treatment or chemical etching methods offers a relatively convenient surface modification route. However, the effects of hydrophilic treatment quickly disappeared and its original surface property was recovered within a few hours or a few days when stored at ambient conditions. Surface treatment based on a single‐layered chemical grafting method rendered an excellent hydrophilic surface with an initial contact angle of <15° and an improved retardation of surface aging. However, the contact angle of the modified PEEK specimen gradually increased with time and eventually reached ∼50° after 23 days. A new method for the long‐term stable hydrophilic surface treatment of PEEK using a multilayered chemical grafting strategy was also developed. With this regard, aging of the modified surface could be significantly retarded over ∼90 days. It was believed that the effectiveness of the surface modification and the retarded aging phenomena via the multilayered hydrophilic treatment could be attributed to mechanical and chemical stability of the covalently bonded active surface groups on the grafted polymer networks. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46042.

Surface Modification of Recycled Carbon Fibers by Use of Plasma Treatment

In this study, sized and thermally desized virgin carbon fibers (vCF) as well as recycled carbon fibers (rCF) from a thermal recycling process are plasma treated by a plasma-jet. The effect of two different process gases (nitrogen and dinitrogen monoxide) and the influence of the distance between the plasma source and the fiber surface are studied with the aim of increasing the oxygen and nitrogen concentration on the rCF surfaces. Higher surface coverage of oxygen-and nitrogen-containing functional groups is supposed to lead to a better adhesion between the carbon fiber and the epoxy resin matrix. The elemental compositions and functional groups of the treated carbon fiber surfaces are studied by x-ray photoelectron spectroscopy. The effect of plasma treatment on the fiber properties like tensile strength, tensile modulus and surface roughness is investigated.

Non-thermal plasma mills bacteria: Scanning electron microscopy observations

Non-thermal plasmas hold great promise for a variety of biomedical applications. To ensure safe clinical application of plasma, a rigorous analysis of plasma-induced effects on cell functions is required. Yet mechanisms of bacteria deactivation by non-thermal plasma remain largely unknown. We therefore analyzed the influence of low-temperature atmospheric plasma on Gram-positive and Gram-negative bacteria. Using scanning electron microscopy, we demonstrate that both Gram-positive and Gram-negative bacteria strains in a minute were completely destroyed by helium plasma. In contrast, mesenchymal stem cells (MSCs) were not affected by the same treatment. Furthermore, histopathological analysis of hematoxylin and eosin–stained rat skin sections from plasma–treated animals did not reveal any abnormalities in comparison to control ones. We discuss possible physical mechanisms leading to the shred of bacteria under non-thermal plasma irradiation. Our findings disclose how helium plasma destroys bacteria and demonstrates the safe use of plasma treatment for MSCs and skin cells, highlighting the favorability of plasma applications for chronic wound therapy.

Chemical analysis of plasma-assisted antimicrobial treatment on cotton

This paper explores the use of plasma treatment as a pretreatment process to assist the application of antimicrobial process on cotton fabric with good functional effect. In this paper, antimicrobial finishing agent, Microfresh Liquid Formulation 9200-200 (MF), and a binder (polyurethane dispersion, Microban Liquid Formulation R10800-0, MB) will be used for treating the cotton fabric for improving the antimicrobial property and pre-treatment of cotton fabric by plasma under atmospheric pressure will be employed to improve loading of chemical agents. The chemical analysis of the treated cotton fabric will be conducted by Fourier transform Infrared Spectroscopy.

Strategy To Enhance the Wettability of Bioacive Paper-Based Sensors

This paper reports a potential method that can restore the wettability of bioactive paper-based sensors while maintaining their bioactivity. This study is driven by the need to increase the wettability of the antibody-loaded blood typing paper devices in order to increase the blood typing assaying speed using such paper devices. Plasma treatment is used to improve the wettability of bioactive paper; the protective effect of bovine serum albumin (BSA) to biomolecules against plasma deactivation is investigated. In the first stage, horseradish peroxidase (HRP) was used as a model biomolecule, because of the convenience of its quantifiable colorimetric reaction with a substrate. By using this protection approach, the inactivation of biomolecules on paper during the plasma treatment is significantly slowed down. This approach enables plasma treatment to be used for fabricating paper-based bioactive sensors to achieve strong wettability for rapid penetration of liquid samples or reagents. Finally, we demonstrate the use of plasma treatment to increase the wettability of antibody treated blood typing paper. After the treatment, the blood typing paper becomes highly wettable; it allows much faster penetration of blood samples into the plasma treated testing paper. Antibodies on the paper are still sufficiently active for blood typing and can report patients' blood type accurately.

The use of plasma treatment for simultaneous carbonization and reduction of iron oxide/polypyrrole core/shell nanoparticles

We have previously reported that the silane coating of magnetic nanoparticles (MNPs) of maghemite phase could be used to protect iron oxide cores during plasma heat treatment, and even help to reduce their phase to magnetite with higher magnetization. In this work, an additional layer of an electrically conductive polypyrrole was added on top of the silane-coated MNPs, producing core–shell particles with sizes ranging from 150 to 500 nm. A microwave plasma heat treatment was used to convert the amorphous, already-conductive polypyrrole coatings into a more electrically conductive graphitic structure, while simultaneously reducing the iron oxide phase to magnetite. The treatment produced core–shell particles with better microwave absorption properties over the frequency of 1–18 GHz, with a maximum reflection loss (absorption) of these MNPs at −37 dB at 10.3 GHz for samples containing 70 wt% of plasma-treated core–shell nanoparticles embedded in wax. By comparison, the maximum absorption for the same amount of untreated nanoparticles was only −18 dB at 7.5 GHz. The improved electromagnetic wave absorption properties were due to higher electrical conductivity of the more ordered, graphitic-like polypyrrole shell structures. This relatively simple protocol could thus be used to synthesize highly magnetic and conductive nanocomposites for electromagnetic interference shielding applications, particularly at the high frequency range.

Need for Long-term Follow-up in Enterohemorrhagic Escherichia coli–Associated Hemolytic Uremic Syndrome Due to Late-Emerging Sequelae

The aim of this study was to evaluate the long-term prognosis of children with hemolytic uremic syndrome (HUS). Over a 6-year period, 619 pediatric patients with the clinical diagnosis of HUS were registered in Austria and Germany, and a subset (n = 274) was prospectively followed up for 5 years. Infection with enterohemorrhagic Escherichia coli (EHEC) was confirmed in 79% of cases. Five years after diagnosis, 70% of EHEC-infected patients (95% confidence interval [CI], .63-.76) were fully recovered. The remaining 30% had persistent hypertension (9%), neurological symptoms (4%), decreased glomerular filtration rate (7%), and/or proteinuria (18%). Hypertension and proteinuria developed in a total of 18% of patients who had no sequelae 1 year after the acute phase (95% CI, 12-26). Multivariate logistic regression analysis demonstrated an association between the use of plasma therapy during acute phase and poor long-term outcome (odds ratio, 2.9-13; 95% CI, 2.4-33; P < .05), but this treatment was also used more frequently in severe cases. In contrast, the use of antibiotic therapy in the diarrheal phase and other established risk factors for developing HUS, such as Shiga toxin 2 and EHEC serotypes traditionally considered to be "high risk," were not associated with adverse long-term outcome. In particular, there was no difference between O157 and non-O157 EHEC. This study identified an association between the use of plasma treatment and poor long-term outcome and confirms already known risk factors for poor prognosis. Follow-up investigations for at least 5 years are recommended to detect late-emerging sequelae.

Hydrothermally synthesized TiO2nanopowders and their use as photoanodes in dye-sensitized solar cells

SUMMARY TiO2 nanopowders are synthesized using a hydrothermal process under various conditions. Effects of several hydrothermal conditions are investigated such that the TiO2 nanopowders having optimized size, surface area, crystallinity, and yield are used for the fabrication of photoanodes. The obtained TiO2 photoanodes are subjected to oxygen plasma treatments for various times. As-synthesized and plasma-treated photoanodes are then assembled into dye-sensitized solar cells. The plasma-treated photoanodes exhibit different concentrations of surface C–OH and oxygen vacancies, depending on the plasma treatment times. This leads to dye-sensitized solar cells having different conversion efficiencies. The use of plasma treatment can enhance the cell conversion efficiency by more than 24%. The effects of the photoanode surface condition on the performance of photoanode are discussed. Copyright © 2012 John Wiley & Sons, Ltd.

Use of plasma treatment to grow carbon nanotube forests on TiN substrate

Hydrogen plasma pretreatment is used to enforce the growth of vertically-aligned carbon nanotube forests on TiN substrates. The evolution of the substrate, catalyst, and nanotubes are studied by in situ and ex-situ photoemission and X-ray diffraction in order to understand the growth mechanism. We find that TiN retains its crystallographic structure and its conductivity during plasma pretreatment and nanotube growth, which is confirmed by electrical measurements. Plasma pretreatment is found to favor the growth of nanotube forests by root growth, as it binds the catalyst nanoparticles more strongly to the substrate than thermal pretreatment. We find that plasma pretreatment time should be limited, otherwise poor or no growth is found.

In situ and real-time optical investigation of nitrogen plasma treatment of polycarbonate

Polycarbonates are very attractive polymeric materials with extensive applications in optical technology as well as for replacing conventional rigid substrates, such as glass. The use of plasma treatments has been successfully employed for improving their surface properties and increasing adhesion of subsequent functional coatings. The objective of this study is to employ in situ and real-time Fourier transform infrared spectroscopic ellipsometry for a detailed investigation of the effect of nitrogen plasma treatment using a pulsed DC voltage, on the optical properties of polycarbonates. Measurements taken before, during and after plasma treatment showed the formation of a surface overlayer in which macromolecular chain scission takes place. The evolution of the overlayer thickness and its bonding has been investigated in detail. Also, the study of the surface nano-topography of polycarbonates by atomic force microscopy showed that plasma treatment increases the surface roughness.

One Proposal for Increase in the Grafted Amount of PNIPAAm onto PTFE Plate by Combination Use of Plasma-treatment and Photografting

Poly(tetrafluoroethylene) (PTFE) plates grafted with N-isopropylacrylamide (NIPAAm) as a hydrophilic monomer have been prepared by the combined use of the plasma treatment and photografting. The surface compositions of the grafted PTFE plates were analyzed by ESCA and the thermo-responsive properties followed by contact angle measurements. To obtain a high grafted amount of PNIPAAm, we cured oxygen-plasma-treated PTFE plates in oxygen atmosphere or after being dipped in acetone and methanol. Alternatively, we prepared the PTFE plates through the method of discontinuous and continuous irradiation of oxygen-plasma treatment. Then, the plasma treated PTFE plates were photografted in an aqueous 1.5 mol/dm3 NIPAAm solution. The ESCA spectra revealed introduction of groups containing oxygen and NIPAAm onto PTFE plates. The grafted amount of PNIPAAm onto PTFE increased over continuous oxygen plasma irradiation. Further, the grafted amount of PNIPAAm was proportionally effective to the thermosensitivities of the PTFE-g-PNIPAAm plate.