Effect Of Plasma Pretreatment Research Articles

Effect of Plasma pretreatment and Graphene oxide ratios on the transport properties of PVA/PVP membranes for fuel cells

In this study, a novel proton-conducting polymer electrolyte membrane based on a mixture of polyvinyl alcohol (PVA)/polyvinyl pyrrolidone (PVP) (1:1) mixed with different ratios of graphene oxide (GO) and plasma-treated was successfully synthesized. Dielectric barrier dielectric (DBD) plasma was used to treat the prepared samples at various dose rates (2, 4, 6, 7, 8, and 9 min) and at fixed power input (2 kV, 50 kHz). The treated samples (PVA/PVP:GO wt%) were soaked in a solution of styrene and tetrahydrofuran (70:30 wt%) with 5 × 10−3 g of benzoyl peroxide as an initiator in an oven at 60 °C for 12 h and then sulfonated to create protonic membranes (PVA/PVP-g-PSSA:GO). The impacts of graphene oxide (GO) on the physical, chemical, and electrochemical properties of plasma-treated PVA/PVP-g-PSSA:x wt% GO membranes (x = 0, 0.1, 0.2, and 0.3) were investigated using different techniques. SEM results showed a better dispersion of nanocomposite-prepared membranes; whereas the AFM results showed an increase in total roughness with increasing the content of GO. FTIR spectra provide more information about the structural variation arising from the grafting and sulfonation processes to confirm their occurrence. The X-ray diffraction pattern showed that the PVA/PVP-g-PSSA:x wt% GO composite is semi-crystalline. As the level of GO mixing rises, the crystallinity of the mixes decreases. According to the TGA curve, the PVA/PVP-g-PSSA:x wt% GO membranes are chemically stable up to 180 °C which is suitable for proton exchange membrane fuel cells. Water uptake (WU) was also measured and found to decrease from 87.6 to 63.3% at equilibrium with increasing GO content. Ion exchange capacity (IEC) was calculated, and the maximum IEC value was 1.91 meq/g for the PVA/PVP-g-PSSA: 0.3 wt% GO composite membrane. At room temperature, the maximum proton conductivity was 98.9 mS/cm for PVA/PVP-g-PSSA: 0.3 wt% GO membrane. In addition, the same sample recorded a methanol permeability of 1.03 × 10−7 cm2/s, which is much less than that of Nafion NR-212 (1.63 × 10−6 cm2/s). These results imply potential applications for modified polyelectrolytic membranes in fuel cell technology.

Application of Fragrance Microcapsules onto Cotton Fabric after Treatment with Oxygen and Nitrogen Plasma

Cotton fabric was exposed to low-pressure capacitively coupled plasma to enhance the adsorption and adhesion of fragrance microcapsules (FCM). Two plasma-forming gases, namely oxygen (O2) and nitrogen (N2), were investigated. The untreated and plasma-treated samples were investigated for their morphological changes by scanning electron microscopy (SEM), mechanical properties (breaking force, elongation, and flexural rigidity), and wicking properties. The cotton samples were functionalized with FCM and the effect of plasma pretreatment on the adsorption and adhesion of FCM was evaluated using SEM, air permeability, fragrance intensity of unwashed and washed cotton fabrics, and Fourier transform infrared spectroscopy (FTIR). The results show that the plasma containing either of the two gases increased the wicking of the cotton fabric and that the O2 plasma caused a slight etching of the fibers, which increased the tensile strength of the cotton fabric. Both plasma gases caused changes that allowed higher adsorption of FCM. However, the adhesion of FCM was higher on the cotton treated with N2 plasma, as evidenced by a strong fragrance of the functionalized fabric after repeated washing.

The effect of ageing on bonding performance of plasma treated beech wood with urea-formaldehyde adhesive

In the process of wood bonding, the usage of aged and inactivated wooden elements can cause a reduction in mechanical properties of products containing wood-adhesive joints. Treating wood with an atmospheric air plasma represents a sophisticated technique for surface activation. With this regard, to enhance the bondability of normal beech wood (Fagus sylvatica L.) with urea-formaldehyde (UF) adhesive, a dielectric barrier discharge plasma in floating electrode configuration was implemented. In this study, fresh and aged wood specimen both, untreated and plasma treated, were investigated. X-ray photoelectron spectroscopy revealed promotion of carbon-rich species with ageing, but generation of a new functional oxygen-containing functional groups after plasma treatment. Microscopic observations with scanning electron microscope showed no obvious changes in the wood structure after plasma treatment. Surface oxidation consequently improved the wettability of the wood surface with water and UF adhesive. However, this enhanced wettability slightly diminished over time. As shown with dynamic mechanical analysis, the rheological properties of the UF adhesive in wood-adhesive joints were not affected by aging nor by plasma treatment. The positive influence of plasma treatment and negative impact of substrate ageing to the shear strengths of wood lap-joints were determined using an automated bonding evaluation system. Similarly, the negative effect of wood ageing and the positive effect of plasma pre-treatment were reflected in the bending strengths of the produced laminated veneer lumbers. Results showed that plasma treatment of beech wood improves the bonding performance of both fresh and aged wood.Graphic abstract

Electrothermal Modeling and Analysis of Polypyrrole-Coated Wearable E-Textiles.

The inhomogeneity of the resistance of conducting polypyrrole-coated nylon–Lycra and polyester (PET) fabrics and its effects on surface temperature were investigated through a systematic experimental and numerical work including the optimization of coating conditions to determine the lowest resistivity conductive fabrics and establish a correlation between the fabrication conditions and the efficiency and uniformity of Joule heating in conductive textiles. For this purpose, the effects of plasma pre-treatment and molar concentration analysis of the dopant anthraquinone sulfonic acid (AQSA), oxidant ferric chloride, and monomer pyrrole was carried out to establish the conditions to determine the sample with the lowest electrical resistance for generating heat and model the experiments using the finite element modeling (FEM). Both PET and nylon-Lycra underwent atmospheric plasma treatment to functionalize the fabric surface to improve the binding of the polymer and obtain coatings with reduced resistance. Both fabrics were compared in terms of average electrical resistance for both plasma treated and untreated samples. The plasma treatment induced deep black coatings with lower resistance. Then, heat-generating experiments were conducted on the polypyrrole (PPy) coated fabrics with the lowest resistance using a variable power supply to study the distribution and maximum value of the temperature. The joule heating model was developed to predict the heating of the conductive fabrics via finite element analysis. The model was based on the measured electrical resistance at different zones of the coated fabrics. It was shown that, when the fabric was backed with neoprene insulation, it would heat up quicker and more evenly. The average electrical resistance of the PPy-PET sample used was 190 , and a maximum temperature reading of 43 °C was recorded. The model results exhibited good agreement with thermal camera data.

The Effect of Plasma Pretreatment on the Morphology and Properties of Hitus Coatings

Abstract WC coatings prepared by High Target Utilization Sputtering (HITUS), a relatively new technology, were deposited on three types of substrates. These were silicon (111), steel (100Cr6), and ceramic (WC-Co). The influence of RF plasma power pretreatment on final properties of WC coatings was investigated with two interlayer materials for bonding. The morphology, roughness, and mechanical properties of coatings were studied. The relation between plasma RF power and roughness was found. No significant change in mechanical properties was detected with change in plasma RF power. The dependence of nanohardness and scratch behavior on HITUS WC coatings was investigated.

Effect of Plasma Pre-treatment on the Conductivity of Polypyrrole-coated Cotton Fabric

In this research work, the effect of plasma treatment on cotton fabric prior to in-situ polymerization of polypyrrole is studied. Cotton woven fabric samples are, individually, pre-treated with argon and nitrogen plasma. Samples that were pre-treated with argon plasma and then subjected to in-situ polymerization of polypyrrole show higher conductance in comparison with the sample pre-treated with nitrogen plasma. This is attributed to the increased interfacial bonding of the pyrrole ring with the argon functional groups.

Effect of Plasma Pre-Treatment on the Dyeability of Silk Fabric with Metal-Complex Dye

Plasma technology is an effective way to modify the physicochemical properties of silk fabric. This study was a preliminary study to explore the dyeability of silk fabric with metal complex dyes after treated with plasma technology, which may improve the processability and broaden the application of silk fabric. This study investigated the optimal plasma treatment condition and evaluated treated silk fabric in terms of wettability, surface modification and dyeability. It was found that plasma treatment can enhance the wettability and dyeability of silk fabric via the formation of hydrophilic functional groups in the structure of silk fiber.

The Effect of Plasma Pretreatment and Cross-Linking Degree on the Physical and Antimicrobial Properties of Nisin-Coated PVA Films.

Stable antimicrobial nisin layers were prepared on the carrying medium-polyvinyl alcohol (PVA) films, crosslinked by glutaric acid. Surface plasma dielectric coplanar surface barrier discharge (DCSBD) modification of polyvinyl alcohol was used to improve the hydrophilic properties and to provide better adhesion of biologically active peptide-nisin to the polymer. The surface modification of films was studied in correlation to their cross-linking degree. Nisin was attached directly from the salt solution of the commercial product. In order to achieve a stable layer, the initial nisin concentration and the following release were investigated using chromatographic methods. The uniformity and stability of the layers was evaluated by means of zeta potential measurements, and for the surface changes of hydrophilic character, the water contact angle measurements were provided. The nisin long-term stability on the PVA films was confirmed by tricine polyacrylamide gel electrophoresis (SDS-PAGE) and by antimicrobial assay. It was found that PVA can serve as a suitable carrying medium for nisin with tunable properties by plasma treatment and crosslinking degree.

Effects of Plasma Pretreatment on ZnO Deposition by SILAR on SiO2, HfO2, and Glass Substrates

AbstractZinc oxide (ZnO) films are deposited onto glass, silicon oxide, and hafnium oxide substrates via the successive ionic layer adsorption and reaction (SILAR) method. The substrates are subjected to an oxygen plasma treatment prior to the deposition to increase the hydrophilic character of the film surface and improve the morphological and structural properties of the resulting ZnO films. Crystallinity, surface morphology, and thickness of the films with and without the plasma treatment are thoroughly evaluated by multiple characterization techniques. The oxygen plasma treatment increases the substrate's surface roughness significantly which results in an increase in the nucleation sites. The plasma treatment yields thicker films in all the substrates compared with substrates without the plasma treatment. The thickness of the ZnO deposited on glass substrates increases as the rinsing time increases, while the opposite is observed for films deposited on both silicon and hafnium oxide substrates. The higher porosity of the ZnO films grown on silicon dioxide and hafnium dioxide substrates leads to a higher surface area that increases the removal of the deposited ZnO on these substrates with the rinsing during the SILAR deposition, resulting in an overall thickness reduction of the film.

Effect of plasma pretreatment on durability of sol-gel superhydrophobic coatings on laser modified stainless steel substrates

Superhydrophobic surfaces were generated on stainless steel SS 304 substrates, using a combination of physical as well as chemical modification of the surface and tested for use in biomedical applications. Nanosecond pulsed laser was used for physical modification, i.e. creating nanoscaled roughness on the substrates. An additional chemical modification was performed using fluorosilane-based sol-gel nanocomposite coatings to further improve the hydrophobicity. Presently, the key challenge that such surfaces face, is to possess a substantial durability. In this study, a surface activation technique such as plasma pre-treatment was adopted to improve the adhesion of coatings on the laser treated substrates. The coatings deposited using dip coating technique were cured at 150 °C. The surface morphology and the roughness of the processed substrates and the coated samples were characterized using Atomic Force Microscope and Scanning Electron Microscope. The wettability of the surface was monitored and evaluated throughout the study using water contact angle measurements. Weathering tests and scratch resistance measurements using a crockmeter were carried out to evaluate the durability, which revealed that the adhesion could be improved with plasma treatment of the laser textured substrates, prior to coating deposition. Maximum anti-bacterial activity of up to 90% towards the bacterial species Escherichia coli was found on the substrates coated with the fluorosilane-based superhydrophobic coatings for an exposure time of 30 min, without any addition of external anti-bacterial agents. Thus, the preliminary results obtained from the present investigation were found to be promising and were indicative of use of these surfaces for biomedical applications.

Effect of Plasma Pretreatment on Metal Absorption of Cotton Fabrics

In this research work, effect of plasma on metal absorption of cotton fabric is investigated. For this purpose the Air and Nitrogen plasma were used. Cotton samples were treated with the optimum conditions of plasma. Then both treated and untreated samples were inoculated by Silver and Iron metallic salts. The amounts of metal particle on the surface of samples were analyzed using Inductively Coupled Plasma (ICP) and Scanning Electron Microscope (SEM). The results show that, air plasma is more effective as compared with Nitrogen plasma for improving the metal absorption of cotton fabric. It can be concluded that, plasma can be a useful method for improving the sorption active materials properties.

The Effect of Dyeing Properties of Fixing Agent and Plasma Treatment on Silk Fabric Dyed with Natural Dye Extract Obtained from Sambucus Ebulus L. Plant

In this study, the natural dye extracted from the fruits of Sambucus Ebulus L. (Dwarf Elder) was used to dye silk fabric. Prior to the dyeing process, the samples were exposed to oxygen plasma pre-treatment at low frequency for 1 and 5minutes. Following the plasma pre-treatment, the samples were dyed with the natural dye by the use of conventional and microwave dyeing methods. After dyeing procedure, the samples were treated with three different fixing agents. Finally, the effect of plasma pre-treatment and microwave energy, and type of fixing agent as a dyeing procedure on colour fastness to light, rubbing and washing and also the colour strength of the samples were investigated. According to the results, the increase on plasma treatment time and microwave energy increased the colour strength of samples. The fixing agent treatment did not affect much as the colour fastness properties of dyed samples.

Influence of plasma treatment on CNT absorption of cotton fabric and its electrical conductivity and antibacterial activity

In this study, effect of plasma pretreatment on the absorption of carboxilated carbon nanotubes (CNTs) on the surface of cotton fabrics was investigated. Treated samples were characterised using a Raman spectrophotometer. Also, the morphological properties of samples were studied using a scanning electron microscope. Electrical resistance and interactions between CNTs and plasma-treated cotton functional groups at the surface were also evaluated. Antibacterial activity of cotton fabric when modified by low temperature plasma and stabilised with CNTs was also investigated. Results showed a uniform coating of CNTs on the plasma-treated cotton fabric and it was found that the plasma treatment is effective on improving CNTs absorption by cotton fabric. Generally, cotton fabric characterisation, such as antibacterial activity and electrical conductivity, after plasma treatment and loading CNT are improved.

Novel Approaches in Designing Natural/Synthetic Materials for Environmental Applications

This is one of a series of special issues published in this journal, focusing on the latest advances of designing natural or synthetic materials for using them in environmental applications. The designing of materials is one of the most developing sectors of environmental science. Novel materials can be synthesized having the ultimate goal of an environmental application. In this field many parameters play an important role as biodegradability, reuse/regeneration, cost, and environmental-friendly disposal. Other standards will be also taken into account as conditions of synthesis, possible use in columns, and so forth. This issue includes novel approaches in designing either natural or synthetic materials which will have direct application to environmental targets (dyes, heavy metals/ions, phenols, pesticides/insecticides, nuclear pollutants, etc.).Thematerials described can be used either for gas or liquid use (i.e., adsorption). Extra attention and priority will be given to real samples of environmental pollutants (industrial effluents). Various types of works were selected to be published with wide topics. The technique of molecular imprinting was introduced by G. Z. Kyzas et al. for selectively binding of high-added value metals. Yang et al. reported material developments regarding geotechnical engineering, while Y. Zhang et al. extensively describe the synthesis and characterization of star-shaped block copolymer sPCL-bPEG-GA. S.-W.Myoung et al. investigated the thermal barrier coatings in cyclic thermal exposure as well as the effect of plasma pretreatment on their thermal durability, while some other related topics have been also published, such as the unstable temperature distribution in friction stir welding (by S. Aziz et al.), the designing and simulated characteristics of nanosized InSb based heterostructure devices (by T. D. Subash et al.), and the synthesis of raw materials originated from industrial effluents for bioremediation and phytomining (by S. B. Karman et al.). Under the direction of the editorial team, we showcase advances of organic and inorganic based smart materials and their applications in areas of specific interest such as energy, environment, and health. A total of 7 articles are published in this special issue.

Effects of plasma pre-treatment on surface properties of fabric sputtered with copper

Purpose – In this study, the polyester fabrics were treated with low temperature plasma before Cu sputtering. The effect of oxygen gas plasma pre-treatment on the surface structures, electrical properties, and mechanical properties of samples was investigated. The paper aims to discuss these issues. Design/methodology/approach – A laboratory direct current (DC) magnetron sputter coating system was used to deposit the nanoscale copper (Cu) films onto the surface of polyester plain fabric at room temperature. Findings – The crystal structure of the sputtered copper films did not show any obvious change on the O2-plasma-treated fabric, but the surface roughness and surface particle size increased significantly. Improvement in electrical properties of copper films was closely related to the deposition time. The tensile test results indicated that the mechanical properties of the plasma-treated polyester fabrics were also improved after copper coating. Originality/value – The research reports on the functional textiles, and the experiment results and analysis are original. There is a great potential to commercialize such functional textiles.

Plasma Pre-Treatment of Polyethylene Terephthalate Substrate Influence on the Properties of ZnO Thin Film

In this work, the influences of plasma pre-treatment on polyethylene terephthalate (PET) substrate to the properties of ZnO thin film have been carried out. ZnO thin films were successfully grown on PET substrate by spin coating method. In order to study the effects of plasma pre-treatment, a comparison of treated and untreated condition was employed. Water contact angle measurement had been carried out for PET wettability study prior to ZnO thin film coating. Morphology study of ZnO thin film was performed by scanning probe microscope (SPM). Besides, optical study of the ZnO thin film was done by using UV-vis spectrophotometer. All the measured results show that plasma pre-treatment of PET substrate plays an important role in enhancing the wettability of PET and optical properties of the ZnO thin films. In conclusion, pre-treatment of PET surface is essential to produce higher quality ZnO thin film on this particular substrate in which would pave the way for the integration of future devices.

Effect of Plasma Pretreatment on Thermal Durability of Thermal Barrier Coatings in Cyclic Thermal Exposure

Plasma pretreatment on the top and bond coats was performed and its influence on the thermal durability of thermal barrier coating (TBC) system was investigated through cyclic thermal exposure. Two types of bond coat were prepared by different methods, namely, air plasma spray (APS) and high-velocity oxy-fuel (HVOF), and two kinds of feedstock powder were employed for preparing the top coat in APS process. The better thermal durability was achieved in the vertically cracked TBC with the surface modified bond coat or with the bond coat prepared by APS process. The hardness and fracture toughness values of TBCs increased because of densification of the top coat during cyclic thermal exposure, and the bond coat prepared by HVOF process showed higher values than that by APS process. The TBCs with the surface modified bond coat were more efficient in improving adhesive strength than those without plasma pretreatment on the bond coat. The relationship between microstructure evolution and thermomechanical characteristics of TBCs with plasma pretreatment was discussed in cyclic thermal exposure.

Effect of Plasma Pretreatment Followed by Nanoclay Loading on Flame Retardant Properties of Cotton Fabric

In this research work the effect of plasma treatment with nitrogen gas followed by nanoclay treatment on flame retardancy of cotton fabrics is studied. The flame retardancy of the samples was characterized by limiting oxygen index and the char yield. The thermal decomposition behaviors, the chemical structures and morphologies of the fabrics were investigated using thermo gravimetric analysis, Fourier transform infrared and scanning electron microscopy, respectively, and a possible flame retardant mechanism is discussed. It shows that, nitrogen plasma pretreatment has synergistic effect on nanoclay for improving the flame retardant properties of cotton samples.

Effect of plasma pretreatment on adhesion and mechanical properties of sol-gel nanocomposite coatings on polycarbonate

Adhesion of the coatings to the substrate plays a vital role in improving mechanical properties of sol-gel coatings especially when deposited on plastics. In the present study, an attempt was made to study the effect of atmospheric air plasma surface activation on the adhesion of sol-gel nanocomposite coatings on polycarbonate substrate. The sol was synthesized by the hydrolysis and condensation of an epoxy silane (3-Glycidoxypropyl trimethoxy silane) along with titanium tetraisopropoxide. Coatings were deposited on 100 × 100 mm substrates by spray coating and subsequently subjected to UV curing followed by thermal curing at 130 °C for 1 h. One set of the substrates was subjected to atmospheric air plasma surface pretreatment prior to coating deposition. Coating thickness, adhesion as well as mechanical properties like pencil hardness, scratch resistance and taber abrasion resistance were evaluated for coatings deposited over plasma-treated and -untreated surfaces. It was found that plasma surface pretreatment has improved the pencil hardness from H to 2H and adhesion of coatings from 2B to 4B. Results obtained from the above experiments were discussed on the basis of surface modification using plasma pretreatment.

The effect of plasma pre-treatment on NaHCO3 desizing of blended sizes on cotton fabrics

The influence of the He/O2 atmospheric pressure plasma jet pre-treatment on subsequent NaHCO3 desizing of blends of starch phosphate and poly(vinyl alcohol) on cotton fabrics is investigated. Atomic force microscopy and scanning electron microscopy analysis indicate that the surface topography of the samples has significantly changed and the surface roughness increases with an increase in plasma exposure time. X-ray photoelectron spectroscopy analysis shows that a larger number of oxygen-containing polar groups are formed on the sized fabric surface after the plasma treatment. The results of the percent desizing ratio (PDR) indicate that the plasma pretreatment facilitated the blended sizes removal from the cotton fabrics in subsequent NaHCO3 treatment and the PDR increases with prolonging plasma treatment time. The plasma technology is a promising pretreatment for desizing of blended sizes due to dramatically reduced desizing time.