Corona Plasma Treatment Research Articles

Corona discharge plasma for green de-inking of inkjet printer ink

This work features a new corona discharge plasma technology for de-inking yellow, blue, and red colors on various papers. This work was developed to minimize the chemical and environmental impacts of de-inking processes. A nonchemical contribution, operating at room temperature and atmospheric pressure, reduces the environmental impact of the process. The deinkability factor (DEMLab) values for all papers are determined with the optimal assessment results provided by a 36-mm variation gap at 2-min (blue) and 10-min (yellow and red) plasma exposure times, followed by applied voltages of 20 kV (yellow), 16 kV (blue), and 20 kV (red). The corona discharge plasma led to 48.58% (yellow printed paper), 64.11% (blue printed paper), and 41.11% (red printed paper) deinkability without altering the physical properties of the paper itself. The change in the tensile strength for the plasma-exposed paper was relatively little, less than 10%, compared to that of common recycling. The tensile strength of the untreated white paper was 5065 ± 487.44 N/mm2, and that of the plasma-treated printed paper was 4593 ± 248.47 N/mm2. It appears that there is little impact on the physicochemical properties of paper induced by the corona plasma treatment during the de-inking process.

TiO2-N/Polystyrene photocatalyst-combined Corona Plasma Treatment for Methylene Blue Degradation

<span>This study employed the corona plasma method combined with TiO<sub>2</sub>-N/PS photocatalyst to degrade dye pollutants. The plasma reactor consisted of two needle-shaped stainless steel electrodes connected to a voltage of 8 kV. Methylene blue (MB) solution was used as a model pollutant with varied initial concentrations of 10, 50, and 100 ppm. The degradation efficiency was evaluated based on the absorbance of the degraded MB solution measured using a UV-Vis spectrophotometer. The results exhibited that the longer plasma treatment duration caused the absorbance value of the degraded MB to decrease, and then the MB degradation efficiency increased. MB-10 demonstrated a maximum degradation efficiency of 99.40% after plasma treatment for 30 minutes. Meanwhile, MB-50 and MB-100 reached maximum degradation efficiencies of 95.29 and 86.55% efficiency after plasma treatment for 60 minutes. The greater initial MB concentration caused the longer degradation process. Furthermore, the results revealed no increase in degradation efficiency due to the addition of TiO<sub>2</sub>-N/PS photocatalyst into the plasma treatment. The degradation efficiencies of MB-10, MB-50, and MB-100 under TiO<sub>2</sub>-N/PS-combined plasma treatment for 30 min were 94.48, 81.57, and 5.22%, respectively. This suggests the possibility that the UV light generated during the plasma process cannot activate the TiO<sub>2</sub>-N/PS photocatalyst.</span>

Investigation of surface properties of biocomposite materials modified by corona plasma treatment

Studies aimed at determining the features of printing on biocomposite polymer materials were carried out. It has been found that the untreated composite films have a low adhesion strength at the composite film-paint interface, the surface tension did not exceed 28 mN/m, and the contact wetting angle was greater than 80 degrees. When the surface is activated by the "corona" discharge method, the adhesion properties appear to a greater extent, and with an increase in the processing stress of the "corona" discharge, the adhesion strength also increases. Thus, in a 25 kV surface treatment, the surface tension for the test composites was estimated to be above 40 mN/m and the contact wetting angle was less than 45 degrees. For BHA based on LDPE and TPC of various bases (corn, pea, rice), adhesion strength was evaluated in the range from 2.9 to 3.5 N/cm2, for PCM based on LDPE and ORD - 29 N/cm2. The result of this work is an increase in surface tension due to the appearance of polar groups on the surface of composite films, in particular oxygen-containing C-O and C = O, as confirmed by Fourier IR spectroscopy. Although the adhesion strength at the film-paint interface is increased when the surface of the composite films is activated, it has been observed that for LDPE-based BHC and thermoplastic starch, the adhesion properties are not constant and decrease over time. After two weeks, adhesion strength was evaluated, on average, 1.4 N/cm2. Most likely, BHCs do not transition to the electret state when the surface is activated by "corona" discharge, and external factors such as temperature and humidity act, as a result of which the number of polar groups on the surface decreases. On the contrary, a slight decrease in adhesion strength from 29 to 27 N/cm2 was observed for PCM based on LDPE and OPD, which is due to the chemical nature of the starting components.

FT-IR Spectral Model of Polyester-Cotton Fabrics with Corona Plasma Treatment using Artificial Neural Networks (ANNs)

<p class="Abstract">Corona plasma technology has been studied as a surface modification for the adhesive bonding of polymers. Although corona plasma (C.P.) is becoming more popular in nanotechnology, the influence of corona plasma treatment parameters on the FT-IR spectra is a problem that has yet to be addressed. The purpose of this study is to use an artificial neural network to study the influence of corona plasma (C.P.) treatment parameters on textile polymer and evaluate the ability of this model to predict FT-IR spectral information from FT-IR measurements. In this study, polymers were modified under various corona plasma treatment conditions. We investigated FT-IR spectra information of polymers from FT-IR measurements by varying corona plasma treatment variables. We used three input parameters in this study: wavenumber, voltage, and exposure time—two output parameters: fabric roughness with SEM according to the degree of smoothness and percent transmission with FT-IR. The novel aspect of this study is that we used ANN to model the plasma treatment on polyester-cotton fabrics and the FT-IR spectra accurately enough for the first time. According to this study, the model that used four nodes (neurons) in the hidden layer, three input parameters (x<sub>1</sub>,x<sub>2</sub>,x<sub>3</sub>), and 20 iterations is appropriate for determining fabric surface roughness (S.R.) and percent transmission (T%). Based on this research, the values of R<sup>2</sup> for determining fabric surface roughness (S.R.) and percent transmission (T%) were 99.79 percent and 67.18 percent, respectively. The results showed that the developed ANNs could accurately predict the experimental data in detail. This study is significant because it uses artificial intelligence to calculate and simulate the FT-IR spectra and fabric surface roughness of plasma treatment on textile fabrics. This study's scientific application is that it will help experts, researchers, and engineers understand the implications of plasma on the chemical structure of textile materials.</p>

Surface modification of SiC to improve joint strength via a Corona plasma treatment

The high mechanical and chemical properties of SiC make it difficult to texture and modify its surface using such conventional methods as mechanical machining and wet etching. Among possible alternative strategies, Atmospheric Pressure Plasmas (APPs) could be used, cutting cost and time, but much still has to be understood about their feasibility for the surface treatment of ceramic materials.In this work, the effectiveness of a commercial corona discharge system in modifying the surface of SiC has been evaluated, focusing on its positive effect on the joint strength of adhesively bonded plasma-treated SiC.The objective of the study has been to observe the surface changes, in terms of chemical composition and texture, that take place as a result of exposure to corona plasma and to compare the obtained results with previous studies on laser and low-pressure plasma textured SiC samples. These very first results, derived from characterization and mechanical testing, suggest that this approach could be a promising alternative.

Rapid, Simple, and Inexpensive Spatial Patterning of Wettability in Microfluidic Devices for Double Emulsion Generation.

Water-in-oil-in-water (w/o/w) double emulsion (DE) encapsulation has been widely used as a promising platform technology for various applications in the fields of food, cosmetics, pharmacy, chemical engineering, materials science, and synthetic biology. Unfortunately, DEs formed by conventional emulsion generation approaches in most cases are highly polydisperse, making them less desirable for quantitative assays, controlled biomaterial synthesis, and entrapped ingredient release. Microfluidic devices can generate monodisperse DEs with controllable size, morphology, and production rate, but these generally require multistep fabrication processes and use of different solvents or bulky external instrumentation to pattern channel wettability. To overcome these limitations, we propose a rapid, simple, and inexpensive method to spatially pattern wettability in microfluidic devices for the continuous generation of monodisperse DEs. This is achieved by applying corona-plasma treatment to a select zone of the microchannel surface aided by a custom-designed corona resistance microchannel to strictly confine the plasma-treatment zone in a single polydimethylsiloxane (PDMS) microfluidic device. The properties of PDMS channel surfaces and key microchannel regions for DE generation are characterized under different levels of treatment. The size, shell thickness, and number of inner cores of generated DEs are shown to be highly controllable by tuning the phase flow rate ratios. Using DEs as templates, we successfully achieve a one-step generation and collection of gelatin microgels. Additionally, we demonstrate the biological capability of generated DEs by flow cytometric screening of the encapsulation and growth of yeast cells within DEs. We expect that the proposed approach will be widely used to create microfluidic devices with more complex wettability patterns.

Investigation of the Impact of Cold Plasma Treatment on the Chemical Composition and Wettability of Medical Grade Polyvinylchloride

The impact of the Corona, dielectric barrier discharge, and low pressure radiofrequency air plasmas on the chemical composition and wettability of medical grade polyvinylchloride was investigated. Corona plasma treatment exerted the most pronounced increase in the hydrophilization of polyvinylchloride. The specific energy of adhesion of the pristine and plasma-treated Polyvinylchloride (PVC) tubing is reported. Plasma treatment increased markedly the specific free surface energy of PVC. The kinetics of hydrophobic recovery following plasma treatment was explored. The time evolution of the apparent contact angle under the hydrophobic recovery is satisfactorily described by the exponential fitting. Energy-dispersive X-ray spectroscopy of the chemical composition of the near-surface layers of the plasma-treated catheters revealed their oxidation. The effect of the hydrophobic recovery hardly correlated with oxidation of the polymer surface, which is irreversible and it is reasonably attributed to the bulk mobility of polymer chains.

Development of electrospun nanofibers having novel morphologies via corona plasma treatment

Development of electrospun nanofibers having novel morphologies via corona plasma treatment

Corona plasma modification of polyamide 66 for the design of textile delivery systems for cosmetic therapy

Cosmetic and medical applications of technical textiles are a research expanding field. One of the added values of these new materials would be that they are suitable to contain and release active ingredients in a controlled manner. The influence of the initial state of the surface of polyamide 6.6 (PA66) fibers on the wetting properties of the fibers as well as on the incorporation of caffeine on the fibers and on its release kinetics from the fibers has been investigated. Comparison between industrially-finished PA66 fabrics and laboratory washed fabrics has been done to carry out this study. Furthermore, surface modification of the PA66 fibers by low temperature plasma has been studied regarding the modification of the physical, chemical and topographical properties of the textile fibers. Corona plasma treatment has been investigated to achieve surface modification in the first nanometers of polymer fibers surface in order to modulate the incorporation and the release of caffeine. It has been demonstrated that both initial state of the PA66 surface and prior plasma treatment of the PA66 fibers before the active principle incorporation condition caffeine release kinetics from the textile fibers. The final release percentage increases linearly with the C–O and CO functional groups incorporated by plasma on the surface. It has also been established that the release amounts of caffeine achieved after 8h from the PA66 fabric are in the same order of magnitude than topical doses of commercial gel-based formulations.

Superior Performance of LiFePO4 Aqueous Dispersions via Corona Treatment and Surface Energy Optimization

In lithium-ion battery electrode processing, obtaining good wetting and adhesion of the electrode dispersion to the current collector foil is essential for achieving high capacity and good long-term performance. The surface tension of LiFePO4 aqueous dispersions is much higher than the surface energy of untreated Al foil due to the high surface tension of water (72.8 mN/m), which causes inferior wetting during the coating step. In this work it has been shown that the surface energy of Al foil is significantly increased by corona plasma treatment. Consequently, the wetting and adhesion of the LiFePO4 aqueous dispersion to the Al foil are dramatically improved, as evidenced by contact angle measurements, adhesion energy calculations and interfacial tension calculations. The LiFePO4 cathodes with corona treated Al foil exhibited superior capacity (∼20 mAh/g improvement) with no increase in capacity fade at 0.5C/−0.5C cycling compared to an identical electrode without treatment.

Influence of Corona Plasma Treatment on Polypropylene and Polyamide 6.6 on the Release of a Model Drug

Low-temperature plasma has been studied for the textile industry as an environmentally friendly alternative to conventional finishing treatments but its biomedical applications are limited. The present work is devoted to analyze how plasma treatment modifies the wetting properties of polypropylene and polyamide 6.6 fabrics and its influence on the drug release from these textile materials. Drug release studies from textiles pre-treated by plasma are unexplored and constitute an innovative research that could provide a new way to develop controlled drug delivery systems. Methods of surface analysis for polypropylene and polyamide 6.6, including contact angle measurements, drop test, SEM, as well as drug release studies, using ketoprofen as a model drug, are considered in this research. Results obtained have shown that the increase of the hydrophilic properties of polypropylene and polyamide fabrics with plasma treatment reverts in a higher release of the model drug studied from plasma-treated fabrics.

Shear Reinforcement of Air Plasma for GFRP-Wood Composite

A study of the effect of air corona plasma treatment on the surface of GFRP (glass-fiber reinforced polymers) has been carried out. The aim is to alter the surface in a manner and scale resulting in stronger shear strength between GFRP and wood. The specimens are exposed to air corona discharge with the irradiation time and power being variables. Goniometry is employed to determine the contact angle of GFRP surface. The results show that the plasma treatment leads to the surface contact angle decreasing significantly. The shear strength of shear test specimens using isocyanate adhesive is stronger than that of specimens using epoxy adhesive. The interface of the GFRP-wood composites is also studied by using Fourier transform infrared spectroscopic (FTIR).

The gas barrier coating of 3-aminopropyltriethoxysilane on polypropylene film

Nonporous films were formed on polypropylene (PP) films using 3-aminopropyltriethoxysilane (APTEOS) as the only precursor. The PP film was modified by corona-plasma treatment to provide appropriate adhesion between coating layer and substrate. Gas permeation properties of coating films were evaluated, and the influences of water ratio and film storing time on the gas permeability were investigated. Structural and surface properties of coating layers were characterized by 29Si-NMR, FT-IR, and contact angle analyzer. The APTEOS coating films exhibit much higher barrier properties than PP film. The permeability coefficient of APTEOS coating film with water ratio of 3 is 0.011Barrer for nitrogen, 0.044Barrer for oxygen, and 0.002Barrer for carbon dioxide, while each permeability coefficient of PP bare film is 0.233, 0.858, and 2.886Barrer, respectively. The gas permeability coefficient is increased slowly along with storage time. Although additionally formed siloxane network may lead to a higher inorganic network density, the enhancement of gas permeability during storing period is largely attributed to film-swelling effect by the water vapor from atmosphere.

Preparation of silica-based hybrid materials coated on polypropylene film

In this study, silica-based organic–inorganic hybrid coating materials were prepared by the sol–gel method. Tertaethoxysilane and polyvinyl alcohol were used as the inorganic and organic compounds, respectively. The substrate polypropylene film surface was modified by corona-plasma treatment to provide appropriate adhesion between the coating material and the polymer base film. A silane.coupling agent of vinyltriethoxysilane was also used to improve the adhesion between the base film and the coated layer. The effects of vinyltriethoxysilane in the hybrid materials were investigated using Fourier transform infrared analyses and X-ray diffraction. The vinyl group of vinyltriethoxysilane increased the hydrophobicity of the hybrid materials. The polypropylene films coated with the hybrid materials were characterized by examining their morphology, optical transparency and oxygen permeability. The results showed that the formation of hydrogen bonds between polyvinyl alcohol and the other compounds affected the microstructure of the coating solution and the final oxygen permeation property. Further, although the presence ofvinyltriethoxysilane in the hybrid coating solution could improve adhesion between the coated layer and the polymer base film, it deteriorates the effectiveness of the barrier to prevent of oxygen permeation through the coated film. However, the coated film maintained visible transparency and even enhanced the transmission of long wavelength visible-light owing to refractive index matching.