Plasma Modification Research Articles

Altering the percolation threshold of PA66‐copper hybrid in an electroless copper deposition process by surface activation of the polymer

AbstractIn this study, the impact of three different principles of surface activation techniques for polyamide fibers on the formation of conductive percolation during the subsequent electroless copper deposition process was investigated. The techniques used are (1) polyamide complexation using a solution mixture of calcium chloride, ethanol and water, (2) atmospheric plasma surface treatment and (3) grafting of 2‐hydroxyethylmethacrylate by radical induced polymerization. As a result, the percolation threshold was shifted to lower copper contents. The copper content required to form conductive structures was reduced ranged between 59% and 89%, depending on the activation techniques. Furthermore, the deposition time was reduced by 37%–57%, resulting in a faster build‐up of the percolation on the fabric. Changes in wetting behavior and substrate surface topography were identified to be the main reasons for these observations. While all applied surface activation techniques led to higher copper contents compared to unmodified reference, the atmospheric plasma modification led to the highest copper contents during the deposition process and a more uniform appearance of the metallised layer.Highlights Three different fiber surface activation methods are evaluated. Fiber surface activation increases wetting and polymer‐metal adhesion. Activated polymer surface leads to faster copper deposition and percolation. Atmospheric plasma modification is the most efficient technique.

Enhancing the scaling resistance of corrugated polyvinylidene fluoride hydrophobic membrane in membrane distillation: Impact of CF4 plasma modification, pulse flow, and negative pressure

Membrane distillation (MD) is an emerging technology for brine concentration, but plagued by scaling/fouling/wetting in realistic applications. There has been tremendous progress in the mitigation of scaling via chemical modification to reduce the surface energy and hydraulic operation to change flow state in feed channel. But there still lacks an undisputed cognition yet which approach outperforms the others. To address this issue, this study comprehensively investigates the impact of state-of-the-art technologies on scaling mitigation based on a surface corrugated hydrophobic PVDF membrane with high flux and potential for mass production. The technology selected include CF4 plasma modification, pulse flow, and negative feed pressure from both thermodynamic and hydraulic perspectives. CF4 plasma modification resulted in a low surface energy superhydrophobic surface, but the scaling resistance of the membranes was not significantly improved. Pulse flow effectively mitigated scaling, yet the intrusion of calcium sulfate into the membrane matrix still occurred. Negative pressure at the feed channel created a stable air layer, leading to excellent stable vapor flux and distillation conductivity. The results indicated that the hydraulic operation using negative pressure at feed was an efficient approach for scaling mitigation. This study further elucidated the mechanism underlying the scaling resistance of superhydrophobic membranes and underscored the importance of hydraulic factors in enhancing the scaling resistance in MD.

Plasma Surface Treatment and Application of Polyvinyl Alcohol/Polylactic Acid Electrospun Fibrous Hemostatic Membrane

In this study, an improved PVA/PLA fibrous hemostatic membrane was prepared by electrospinning technology combined with air plasma modification. The plasma treatment was used to modify PLA to enhance the interlayer bonding between the PVA and PLA fibrous membranes first, then modify the PVA to improve the hemostatic capacity. The surfaces of the PLA and PVA were oxidized after air plasma treatment, the fibrous diameter was reduced, and roughness was increased. Plasma treatment enhanced the interfacial bond strength of PLA/PVA composite fibrous membrane, and PLA acted as a good mechanical support. Plasma-treated PVA/PLA composite membranes showed an increasing liquid-enrichment capacity of 350% and shortened the coagulation time to 258 s. The hemostatic model of the liver showed that the hemostatic ability of plasma-treated PVA/PLA composite membranes was enhanced by 79% compared to untreated PVA membranes, with a slight improvement over commercially available collagen. The results showed that the plasma-treated PVA/PLA fibers were able to achieve more effective hemostasis, which provides a new strategy for improving the hemostatic performance of hemostatic materials.

Hydrophobization of Cold Plasma Activated Glass Surfaces by Hexamethyldisilazane Treatment.

The objective of this study was to investigate the modification of glass surfaces by the synergistic combination of cold plasma and chemical surface modification techniques. Glass surface hydrophobicity was obtained as a result of various plasma and deposition operational conditions. The mechanisms governing the hydrophobization process were also studied. Glass plates were activated with plasma using different gases (oxygen and argon) at different treatment times, ranging from 30 to 1800 s. Then, the plasma-treated surfaces were exposed to hexamethyldisilazane vapors at different temperatures, i.e., 25, 60, and 100 °C. Complete characterization, including contact angle measurements, surface free energy calculations, 3D profilometry, X-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy, and scanning electron microscopy, was accomplished. It was found that the extent of the hydrophobicity effect depends on both the plasma pre-treatment and the specific conditions of the hexamethyldisilazane deposition process. Plasma activation led to the formation of active sites on the glass surface, which promoted the adsorption and reaction of hexamethyldisilazane species, thereby inducing surface chemical modification. Longer plasma pre-treatment resulted in stronger modification on the glass surface, resulting in changes in the surface roughness. The largest water contact angle of ≈100° was obtained for the surface activated by argon plasma for 1800 s and exposed to hexamethyldisilazane vapors at 25 °C. The changes in the surface properties were caused by the introduction of the hydrophobic trimethylsilyl groups onto the glass surface as well as roughness development.

Air Plasma Modification of Graphite-Based Electrode for Improved Performance of Aqueous Redox Flow Batteries

Graphite felt is widely utilized as a porous carbon electrode in aqueous redox flow batteries (RFBs). However, its inherent hydrophobic nature and limited electrochemical activity present challenges. While the correlation between RFB performance and electrode properties has been extensively studied for vanadium chemistry and other inorganic redox active materials, it remains scarce in literature for organic systems. In this study, we employ air plasma treatment, known for its controllability, solvent-free nature, and short treatment duration, to modify commercially available graphite felt for RFB applications. A comprehensive analysis is conducted to establish correlations between plasma treatment, physical properties, electrochemical characteristics, and overall cell performance in aqueous RFBs. Comparative evaluation reveals a significant enhancement, with treated graphite felt exhibiting an 85% increase in capacity at 140 mA cm−2 compared to its pristine counterpart. By intentionally utilizing authentic RFB electrodes and employing state-of-the-art ferrocyanide posolyte, this study underscores the crucial role of the interface, even for rapid (reversible) redox-active materials utilized in AORFBs.

Designing innovative PAni-based adsorbents for CO2 capture via in-situ nitrogen plasma modification for sustainable development

Carbon dioxide (CO2) capture is a critical strategy in the fight against climate change. By implementing this innovative technology, CO2 emissions from diverse sources will be captured and neutralized, thereby mitigating global warming. For this purpose, novel sorbents were developed in this work by loading TiO2 and ZnO nanofillers into a polyaniline (PAni) system to form PAni–TiO2 (PT) and PAni–ZnO (PZ) composites. Following that, in-situ nitrogen (N2) plasma treatments were applied for 5 min to improve their surface nature and physiochemical properties. The CO2 capture qualities of modified PT and PZ sorbents were investigated, as well as physical assessments of their microstructure, nuclear magnetic resonance (NMR), morphology, contact angle, roughness, electrical optical, reactivity, stability, and adsorption capability, hardness, softness and electrophilicity properties. Bombardment of high-energy plasma species for 5 min was sufficient to optimize the crystallite size and crystallinity degree in both the PT5 and PZ5 systems. These enhancements may be related to the growth of protonated benzoid rings -NH+- as a result of plasma modifications to the structure of PAni and its transformation into emerald salt. In a similar vein, the SEM micrographs, porous topography and hydrophilic nature of the PAni composites varied with respect to the type of nanofillers and plasma level. The plasma treatment provided additional oxygen-containing functional groups as active sites for chemical interactions, including CO2 via chemisorption or physisorption, facilitating further reduction. Additionally, plasma activities assisted in shifting to a rougher surface (i.e.,Ra = 3.83 µm) as well as optimizing the energy band gap (1.57 eV), which can accommodate more CO2 molecules, thereby improving the capture efficiency. Moreover, the findings indicate that PZ5 is more desirable for CO2 adsorption since it possesses a 2.52-fold greater CO2 adsorption energy (-0.079 a.u) than pristine PZ0. In the future, our work opens up exciting new prospects to achieve desired performance from CO2 capturing compounds utilizing plasma technology.

Effect of plasma treatment of Ag/ZnO hybrid photocatalysts on the optical properties and morphology of Ag nanoparticles

Subject of study. This study investigates Ag/ZnO hybrid photocatalysts and the role of silver nanoparticles as the active phase of these hybrid photocatalysts after treatment with low-temperature plasma generated from a dielectric barrier discharge. Aim of study. The aim is to determine how plasma treatment affects the optical properties and morphology of silver nanoparticles in Ag/ZnO hybrid photocatalysts as well as to explore the relationship between plasma-induced morphological changes and the photocatalytic activity of Ag/ZnO in the photodegradation of methyl orange and caffeine. Method. Ag/ZnO hybrid photocatalysts and silver nanoparticle ensembles were treated with dielectric barrier discharge plasma in air at normal pressure. The photocatalytic performances of the original and plasma-treated materials were evaluated through the degradation of methyl orange and caffeine in aqueous solutions under ultraviolet light, and the concentrations of methyl orange and caffeine were measured by spectrophotometry. The effects of plasma modification were analyzed using photoluminescence spectroscopy, spectrophotometry, and atomic force microscopy. Main results. A plasma-induced reduction in the size of silver nanoparticle agglomerates was observed, accompanied by an increase in the number of individual nanoparticles. The nanoparticle size changes were dependent on the energy and duration of plasma treatment. Additionally, the plasma treatment of ZnO-based hybrid photocatalysts led to a marked increase in the fluorescence lifetime of ZnO, contributing to enhanced photocatalytic activity in the degradation of organic pollutants in aqueous media. Practical significance. Improving the efficiency of Ag/ZnO photocatalysts for the removal of organic impurities from aqueous media through photodegradation represents a significant advancement in environmental management.

Comparative study of iodine-doped and undoped pyrrole grafting with plasma on poly (glycerol sebacate) scaffolds and its human dental pulp stem cells compatibility.

This study addresses the morphological and chemical characterization of PGS scaffolds after (6, 12, 18, 24, and 30 min) residence in undoped pyrrole plasma (PGS-PPy) and the evaluation of cell viability with human dental pulp stem cells (hDPSCs). The results were compared with a previous study that used iodine-doped pyrrole (PGS-PPy/I). Analyses through SEM and AFM revealed alterations in the topography and quantity of deposited PPy particles. FTIR spectra of PGS-PPy scaffolds confirmed the presence of characteristic absorption peaks of PPy, with higher intensities observed in the nitrile and -C≡C- groups compared to PGS-PPy/I scaffolds, while raman spectra indicated a lower presence of polaron N+ groups. On the other hand, PGS scaffolds modified with PPy exhibited lower cytotoxicity compared to PGS-PPy/I scaffolds, as evidenced by the Live/Dead assay. Furthermore, the PGS-PPy scaffolds at 6 and 12 min, and particularly the PGS-PPy/I scaffold at 6 min, showed the best results in terms of cell viability by the fifth day of culture. The findings of this study suggest that undoped pyrrole plasma modification for short durations could also be a viable option to enhance the interaction with hDPSCs, especially when the treatment times range between 6 min and 12 min.

Influence of Low-Pressure Oxygen Plasma Modification on the Mechanical and Surface Charactertstics of Epoxy Composites Reinforced by Eco-Friendly Banana /Sisal Fibers

Influence of Low-Pressure Oxygen Plasma Modification on the Mechanical and Surface Charactertstics of Epoxy Composites Reinforced by Eco-Friendly Banana /Sisal Fibers

Enhancement Mechanism of the Difference of Hydrophobicity between Anode and Cathode Active Materials from Spent Lithium-Ion Battery Using Plasma Modification

Enhancement Mechanism of the Difference of Hydrophobicity between Anode and Cathode Active Materials from Spent Lithium-Ion Battery Using Plasma Modification

Effects of various cold plasma atmospheres and external influencing factors on the adsorption of formaldehyde gas by bamboo-based carbon microfibers

To effectively enhance the adsorption performance of gaseous formaldehyde (HCHO) by bamboo-based carbon microfibers (BCMFs), the active oxygen (O) and nitrogen (N)-containing functional groups were rapidly introduced by cold plasma. The effects of plasma time, plasma atmospheres including oxygen (O2), nitrogen (N2), air, and argon (Ar) as well as ambient temperature, flow rate, and initial concentration of gaseous HCHO on the adsorption performance of BCMFs were comprehensively investigated. The typical kinetic, isothermal, and thermodynamic models were also evaluated. The O2-plasma activated BCMFs showed the most serious etching effects among four atmospheres. The adsorption capacities were ranked as BCMF-800-N-10 (203.87 mg g−1) > BCMF-800-Ar-10 (166.26 mg g−1) > BCMF-800-Air-10 (151.28 mg g−1) > BCMF-800-O-10 (144.21 mg g−1), which were 112.99%, 73.69%, 58.04%, and 50.66% higher than the control, respectively. The O–CO and pyrrolic N groups were more easily formed onto BCMF-800-N-10. The Langmuir and the Freundlich models displayed the excellent fitting properties. The optimal kinetic model tended to transfer to the pseudo-second-order from the pseudo-first-order after cold plasma modification. The BCMFs activated by plasma showed a synergistic single/multi-layer adsorption mechanism with a complex physicochemical adsorption. The HCHO adsorption performance was positively correlated with its concentrations but negatively correlated with environmental temperature.

Nanosecond pulsed discharge plasma modified porous polymer adsorbent materials for efficient removal of low‐concentration bisphenol A in liquid

AbstractThe efficient removal of low‐concentration endocrine disruptors is crucial for the protection of the aquatic environment. In this study, porous polymer adsorbent materials were modified by nanosecond pulsed discharge plasma to achieve efficient adsorption of low‐concentration bisphenol A (BPA). The removal efficiency of BPA reached 99% after 10 min of plasma modification at a pulse peak voltage of 28 kV, which increased by 25.8% compared to the raw materials. This enhancement was attributed to the increase of active sites and oxygen‐containing functional groups. The adsorption behaviors of the porous polymer materials were primarily dominated by monolayer chemisorption. Subsequently, comparative experiments further verified the high‐efficiency adsorption performance of porous polymer materials after plasma treatment.

Enhancing CFRP laminates with plasma jet arrays: A study of interlaminar mechanical properties

AbstractThis study delves into the efficacy of plasma jet array treatment in bolstering the interlaminar toughness of Carbon Fiber Reinforced Polymer (CFRP) prepregs, a crucial parameter for their deployment in high‐performance domains. Employing high‐frequency pulsed microsecond plasma jet arrays for surface modification, this research not only demonstrated a 19.49% upsurge in peak load capacity but also a remarkable 29.94% enhancement in Mode I interlaminar fracture toughness, as evident from Double Cantilever Beam (DCB) tests. Furthermore, the surface wettability improvements were underscored by a substantial decrease in water contact angle from 108.33° to 31.45° and a total surface energy augmentation from 12.20 to 64.16 mN/m, post a 1‐min plasma treatment. X‐ray Photoelectron Spectroscopy (XPS) results indicated an appreciable rise in oxygen functionalities, suggesting enhanced resin‐fiber bonding. Additionally, Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM) analyses revealed notable decreases in surface roughness and microscale defects, contributing to smoother surfaces conducive to better adhesive bonding and reduced manufacturing defects. These multifaceted improvements, stemming from alterations in surface chemistry and topography, underpin the significant potential of plasma treatment in advancing CFRP laminate applications requiring superior durability and mechanical resilience.Highlights A plasma jet arrays method to enhance CFRP's interlaminar properties was studied. The influence mechanism of plasma modification was revealed in detail. The interlayer toughening mechanism of CFRP after plasma modification is proposed.

Influence of duoplasmatron ion source plasma treatment on multi-axial knitted structure reinforced glass fiber composites

The present study investigates the impact of glow discharge cold plasma-induced duoplasmatron ion source on the mechanical properties of multi-axial knitted structure reinforced glass fiber composites. Analysis of failure location and mode in bending tests was conducted using the acoustic emission method. The results reveal that the tensile and bending strength of the multi-axial structure reinforced glass fiber composites treated with oxygen/nitrogen plasma had increased by 21.84% and 37.28%, respectively. In contrast, when treated with oxygen/argon plasma, the corresponding enhancements were 17.47% and 24.16%, respectively. These results indicate that oxygen/nitrogen plasma treatment yields superior mechanical properties to oxygen/argon treatment. The accumulated acoustic emission energy in the multi-axial structure reinforced glass fiber composites subjected to oxygen/nitrogen and oxygen/argon treatments was 25.49% and 62.39% lower than untreated samples, respectively. The failure mode observed in the untreated composites was matrix cracking, whereas the composites treated with dual plasma exhibited interface debonding. The dual plasma modification enhanced fiber wettability and surface roughness, facilitating increased contact area between the fiber and matrix and promoting the overall bonding performance between the two components. Taken together, our findings suggest that duoplasmatron ion source treatment enhanced the interface bonding and mechanical properties of the multi-axial structure reinforced glass fiber composites.

Unveiling the Potential of Covalent Organic Framework Electrocatalyst for Enhanced Oxygen Evolution.

The potential for sustainable energy and carbon neutrality has expanded with the development of a highly active electrocatalyst for the oxygen evolution reaction (OER). Covalent Organic Frameworks (COF) have recently garnered attention because of their enormous potential in a number of cutting-edge application sectors, such as gas storage, sensors, fuel cells, and active catalytic supports. A simple and effective COF constructed and integrated by post-alteration plasma modification facilitates high electrocatalytic OER activity under alkaline conditions. Variations in parameters such as voltage and treatment duration have been employed to enhance the factor that demonstrates high OER performance. The overpotential and Tafel slope are the lowest of all when using an optimized parameter, such as plasma treatment for 30 min utilizing 6 kV of voltage, PT-30 COF, measuring 390 mV at a current density of 10 mA.cm-2 and 69 mV.dec-1, respectively, as compared to 652 mV and 235 mV.dec-1 for the Pristine-COF. Our findings provide a method for broadening the scope by post-functionalizing the parent framework for effective water splitting.

Influence of Oxygen/Argon/Nitrogen multi-component plasma modification on interlayer toughening of UHMWPE fiber reinforced composites

The study reveals the influence of glow discharged three gas sources of Oxygen/Argon/Nitrogen plasma modification on interlayer toughening of ultra-high molecular weight polyethylene (UHMWPE) fiber reinforced composite. The failure modes under bending, tensile and interlayer fracture toughness testing were analyzed through acoustic emission (AE) technology. The results showed that Oxygen/Argon/Nitrogen multi-component plasma modified fiber introduced more hydrophilic groups such as hydrogen and hydroxyl groups, and significantly enhanced the binding of fiber and matrix. The GⅠC (Mode-I interlaminar fracture toughness) of multi-component plasma modified composites exhibited increased by 61.67 %, 40.88 % and 18.01 % compared to untreated, Oxygen and Oxygen/Argon plasma, respectively, while GⅡC (Mode-II interlaminar fracture toughness) increased by 38.57 %, 25.57 % and 23.09 %. AE cluster analysis exhibited that multi-component plasma modified composites formed an energy dissipation mechanism dominated by fiber breakage. Additionally, the oxygen, argon, and nitrogen plasma modification have a synergistic effect on interlayer toughening.

Enhancing Graphene Nanoplatelet Reactivity through Low-Temperature Plasma Modification.

Graphene-based materials have great potential for applications in many fields, but their poor dispersion in polar solvents and chemical inertness require improvements. Low-temperature plasma allows the precise modification of materials, improving the physicochemical properties of the surface and thus creating the possibility of their potential use. Plasma treatment offers the possibility of introducing oxygen functional groups simply, rapidly, and in a controlled way. In this work, a systematic investigation of the effect of plasma modification on graphene nanoplatelets has been carried out to determine the optimal plasma parameters, especially the exposure time, for introducing the highest amount of oxygen functional groups on a surface. Different gases (O2, CO2, air, Ar, and C2H4) were used for this purpose. The chemical nature of the introduced oxygen-containing functionalities was characterized by X-ray photoelectron spectroscopy, and the structural properties of the materials were studied by Raman spectroscopy. The plasma-induced changes have been shown to evolve as the surface functionalities observed after plasma treatment are unstable. The immersion of the materials in liquids was carried out to check the reactivity of carbons in postplasma reactions. Stabilization of the material's surface after plasma treatment using CH3COOH was the most effective for introducing oxygen functional groups.

Effect of Non-Thermal Sulfur Hexafluoride Cold Plasma Modification on Surface Properties of Polyoxymethylene.

X-ray photoelectron spectroscopy was employed to reveal the differences in the chemical structure of the topmost layer after plasma modification. It was found out that changes in the surface properties of the polymer could be observed even after 20 seconds of treatment. The surface becomes hydrophobic or superhydrophobic, with the water contact angles up to 160 degrees. Morphological changes and increased roughness can be observed only in the nanoscale, whereas the structure seems to be unaffected in the microscale. As a result of plasma modification a permanent hydrophobic effect was obtained on the polyoxymethylene surface.

Plasma-Enhanced Alginate Pre-Treatment of Short Flax Fibers for Improved Thermo-Mechanical Properties of PLA Composites

This research centered on enhancing the mechanical properties of sustainable composite materials made from short flax fibers. Challenges associated with fiber–matrix adhesion and moisture absorption were systematically addressed. A water–alginate pre-treatment, combined with plasma modification, was employed to stabilize the fibers, ensuring their optimal preparation and improved compatibility with biopolymers. A thorough investigation of the effect of the plasma modulation using a duty cycle (DC) was conducted, and extensive physicochemical and mechanical analyses were performed. These efforts revealed conditions that preserved fiber integrity while significantly improving surface characteristics. Techniques such as optical emission spectroscopy (OES), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and Dynamic Mechanical Analysis (DMA) were utilized, providing a comprehensive understanding of the transformations induced by the plasma treatment. The findings underscored the critical role of alginate and precise plasma settings in enhancing the mechanical properties of the composites. Ultimately, this study made a substantial contribution to the field of eco-friendly materials, showcasing the potential of short flax fibers in sustainable composite applications and setting the stage for future advancements in this area.

Enhanced Photocatalytic Performance of UiO-66-NH2 MOFs by Ar Plasma Modification for Reduction of Cr (VI)

Enhanced Photocatalytic Performance of UiO-66-NH₂ MOFs by Ar Plasma Modification for Reduction of Cr (VI)