Atmospheric Plasma Processing Research Articles

Changes in the structure and barrier properties induced by corona atmospheric plasma process applied on wet gelatin layers for packaging film applications

Fish gelatin is a by-product of the agri-food sector, derived from fish processing waste that can be used as or along a packaging material in direct contact with food while maintaining biodegradable properties. The aim of this work was to apply the corona discharge process on fish gelatin hydrogels and to analyse the properties of resulting films after drying. The understanding of changes in the physical or chemical structure of the gelatin layer was focused on at molecular level. Changes in the surface free energy due to corona treatment displayed an increase of the hydrophobicity at highest power tested. Results demonstrated the plasma's species crossed the gelatin layer and induces weak changes. Indeed, the permeability to various gases was maintained even at high power, confirming that corona discharge systems are suitable devices for treating wet hydrogels without significant degradation of the gelatin layer.

Multimodal intelligent approach to low-temperature atmospheric plasma processing of apple slices before drying.

This study presents a comprehensive analysis of the impact of plasma treatment on the browning inhibition. A 30 min plasma treatment resulted in a pronounced decrease in the concentration of flavan-3-ols, which play a pivotal role in antioxidant defense and browning prevention. This significant reduction is likely due to plasma-induced oxidative stress, which can lead to the breakdown of these compounds or their conversion into other phenolic structures. Simultaneously, a slight increase in dihydrochalcones and flavonols was observed, suggesting a selective effect of plasma on different phenolic classes. The increase in these compounds could be attributed to the plasma's ability to induce specific reactions that generate these phenolics from other precursors present in the apples. The reduction in flavan-3-ols may affect the antioxidant capacity and health benefits associated with the apples, while the increase in dihydrochalcones and flavonols could have a positive impact on the flavor profile and potential health-promoting properties. Moreover, these modifications could contribute to the extension of shelf-life and maintenance of sensory qualities, making plasma treatment a valuable tool in the food industry for enhancing product stability and consumer appeal.

Atmospheric Pressure Plasma Functionalization of Sealed PDMS Microfluidics: Application to Capillary Pumping and Enhanced Cell Growth.

Microfluidic devices serve as essential tools across diverse fields like medicine, biotechnology, and chemistry, enabling advancements in analytical techniques, point-of-care diagnostics, microfluidic cell cultures, and organ-on-chip models. While polymeric microfluidics are favoured for their cost-effectiveness and ease of fabrication, their inherent hydrophobic properties necessitate surface functionalization, often post-sealing. Here, we introduce a versatile apparatus for functionalizing sealed microfluidic devices using atmospheric plasma processing, with a focus on PDMS (polydimethylsiloxane) microfluidics. Through meticulous analysis of surface properties and capillary speed, before and after plasma treatment, along with a comparison between vacuum and atmospheric plasma functionalization methods, we demonstrate the efficacy of our approach. Subsequent experimentation within 3D PDMS microfluidic chambers, combining atmospheric pressure plasma treatment with collagen coating to facilitate mesenchymal stem cells (MSCs) growth over five days, reveals enhanced initial cell adhesion and proliferation, highlighting the potential of our method for improving cell-based applications within microfluidic systems.

In-package cold atmospheric plasma processing for shelf-life extension of gilthead seabream (Sparus aurata) fillets.

In-package cold atmospheric plasma (CAP) processing, which refers to the generation of CAP inside a sealed package, enables a local disinfecting reaction, allowing no post-process contamination and extending the shelf-life (SL) of perishable food products, such as fresh fish. In the present study, four in-package CAP treatments, differing in frequency and processing time, were applied on fresh gilthead seabream (Sparus aurata) fillets, prepacked in low-permeability pouches. Fish SL was evaluated during isothermal storage at 2°C, whereas untreated packaged fillets were used as control samples. The SL assessment of the fish fillets was based on microbial enumeration of total aerobic mesophilic count (TMC), total aerobic psychrotrophic count (TPC), Pseudomonas spp., Enterobacteriaceae, and lactic acid bacteria (LAB), pH measurement, determination of color and texture parameters, lipid oxidation, total volatile basic nitrogen (TVB-N) measurement, and sensory evaluation. All CAP treatments were effective against microbial inhibition in fish fillets, especially regarding TMC, TPC, and Pseudomonas spp., resulting in maximum reduction of 1.49, 1.24, and 1.43logCFU/g, respectively, compared to the control samples after 16 days of storage. However, minor effect was observed against Enterobacteriaceae and no effect against LAB. CAP processing did not affect the color and texture parameters of fish fillets, and TVB-N production was slightly reduced in CAP-treated samples; however, lipid oxidation was accelerated, especially at the more intense processing conditions, by a maximum of 75.5%. The results of the study indicated that in-package CAP processing could be effectively applied for inhibiting spoilage during refrigerated storage and extending SL of fresh fish fillets. PRACTICAL APPLICATION: In-package cold atmospheric plasma (CAP) processing was tested on gilthead seabream fillets, a highly perishable product with high commercial potential if its shelf-life can be extended through minimal processing. The food industry could benefit from in-package CAP technology as it is a cost effective nonthermal processing method while preventing post-processing contamination of the products. Although in-package CAP processing has not been extensively tested on fish, this study examined the quality and shelf-life of a highly perishable fish species, and the results could be further used as a reference for processing optimization of the CAP treatments.

Application of Near-Infrared Spectroscopy and Aquaphotomics in Understanding the Water Behavior during Cold Atmospheric Plasma Processing

Plasma-activated water (PAW), obtained by exposing liquid to cold atmospheric plasma (CAP) for a period, has gained widespread attention for its potential as anti-bacterial, anti-infective, anti-cancer and other biological agents. It is important to understand the PAW behavior and express it in a ‘visualization’ form. Near-infrared spectroscopy (NIR) and aquaphotomics were introduced in this study to investigate the PAW spectra to visualize the water molecular species and try to analyze the production and changes of the active substances in PAW. Second-order derivative, PCA and PLS were applied to identify specific peaks to construct the aquagram and reference method for the ROS assay used to prove the spectral results. The results showed that a longer treatment time resulted in greater spectral changes which could be visualized with 12 water matrix coordinates (WAMACS) and the change trends were in accordance with the ROS concentration variations. Furthermore, during PAW sample storage, there were fluctuations in spectral changes, with a general trend of increase, and a gradual decrease in ROS concentration due to active substance reactions in PAW. In conclusion, this study presents a new perspective on examining the water behavior of PAW and offers a new method to explore cold plasma biomedical materials.

Plasma modification of graphene nanoplatelets surfaces

Atmospheric plasma processing, which combines the efficacy of chemical processes and the safety of physical processes, has been used to modify the surface characteristics of graphite-based materials. In this work, two distinct plasma source gases, C4F8 and O2, with the addition of a rotary reactor were used. The effectiveness of modifying the basal plane of intercalated graphite nanoplatelets (GnP) was investigated with various analytical techniques and the visual observation of the dispersion of these plasma-treated GnP in solvents was also reported. It is shown that this low-temperature plasma processing technique can be used to successfully modify the GnP surface without significantly changing the intrinsic structure of the GnP, which is desirable in many applications. With the C4F8 plasma treatment, the immersion characteristics in solvents can be tuned and the functional groups present on the surface can be tailored to produce desired bonding environments. This surface chemistry tunability will provide the needed functionalities in creating graphene-containing composite materials.

Surface Modification of Silicon Carbide Wafers Using Atmospheric Plasma Etching: Effects of Processing Parameters.

Silicon carbide wafer serves as an ideal substrate material for manufacturing semiconductor devices, holding immense potential for the future. However, its ultra-hardness and remarkable chemical inertness pose significant challenges for the surface processing of wafers, and a highly efficient and damage-free method is required to meet the processing requirements. In this study, atmospheric plasma processing was used to conduct point-residence experiments on silicon carbide wafers by varying process parameters such as Ar, CF4, and O2 flow rate, as well as processing power and the distance between the plasma torch and the workpiece. We investigate the effects of these on the surface processing function of atmospheric plasma etching and technique for surface modification of silicon carbide wafers, evaluating the material removal rates. Then, according to the experimentally derived influence law, suitable parameter ranges were selected, and orthogonal experiments were designed to determine the optimal processing parameters that would enable rapid and uniform removal of the wafer surface. The results indicate that the volume removal rate of the plasma on the silicon carbide wafer achieves its maximum when the input power is 550 W, the processing distance between the plasma torch and workpiece is 3.5 mm, and when the Ar, CF4, and O2 flow rates are 15 SLM, 70 SCCM, and 20 SCCM, respectively.

Сушка яблочных чипсов с применением интеллектуальной обработки низкотемпературной атмосферной плазмой

The food industry needs more effective drying procedures that would maintain the quality of the original fruit or vegetable. Infrared drying combined with advanced electrophysical technologies may be a perfect solution. The present research objective was to study the effect of low-temperature atmospheric gas plasma treatment on the drying efficiency of apple slices.
 The research featured apples of the Idared variety (Russia) sliced into pieces of 5, 7, and 10 mm. The experiment involved the parameters of drying kinetics and moisture diffusion. The quality of the apple slices was assessed by the total content of phenols and flavonoids, generalized antiradical activity, color characteristics, and the Fourier transform infrared (FT-IR) spectrum.
 The electropores induced by the cold atmospheric gas plasma processing had a tree-like structure. The pre-treatment reduced the drying time by 18.0, 13.0 and 10.5% for the samples with a thickness of 5, 7, and 10 mm, respectively. The specific energy consumption decreased by 15–18%, depending on the slice thickness. The pre-treatment also increased the total content of phenols, flavonoids, and antiradical activity by 2.5–14.3, 19.1–25.9, and 8.3–35.4%, respectively.
 Therefore, the pre-treatment with cold atmospheric gas plasma reduced the drying time and preserved the original biologically active compounds in dried apple slices.

Influence of atmospheric and vacuum plasma processing on the organic composition of araça-boi (Eugenia stipitata) juice

Cold plasma is a novel non-thermal technology that is still under development. Cold plasma treatment of food products induces a wide range of chemical changes in food compounds, several of which can improve nutritional quality. Understanding the chemical changes caused during plasma treatment is essential to enhance food quality and avoid the formation of undesired compounds. This investigation addressed the influence of two cold plasma technologies, glow discharge plasma and dielectric barrier discharge plasma, on the organic composition of araça-boi (Eugenia stipitata) juice, which is rich in sugars, organic and amino acids. The chemical composition of the juice was assessed by 1H nuclear magnetic resonance coupled with chemometrics. The effects of excitation frequency, processing time, and plasma flow rate were investigated. Glow discharge plasma and dielectric barrier discharge plasma application tended to decrease the concentration of glucose (33%), fructose (31%), malic acid (25%), and amino acids while increasing sucrose content (23%). Overall, plasma processing changed the juices’ alcohol, sugar, and amino acids content, primarily by reducing the concentration of cysteine (33%), alanine (42%), and methionine (43%). However, the dielectric barrier discharge plasma tended to slightly increase the amino acid content (up to 9%) when operating at 200 Hz.

Atmospheric Plasma and UV Polymerisation for Developing Sustainable Anti-Adhesive Polyethylene Terephthalate (PET) Surfaces

Enhancing the hydrophilicity of polymeric materials is an important step for achieving anti-adhesiveness. Thus, in this study, atmospheric plasma as a pre-treatment was combined with a UV grafting process to obtain a durable surface modification on polyethylene terephthalate (PET). The most promising conditions for the atmospheric plasma process were found to be 15 kW power and 4 m/min speed, leading to a contact angle reduction from 70 ± 6° to approximately 30°. However, it was observed that these values increased over time due to the ageing and washing of the PET surface, ultimately causing it to recover its initial contact angle. Therefore, the plasma-pre-treated PET samples were further modified through a UV grafting process using sodium acrylate (NaAc) and 3-sulfopropyl acrylate potassium salts (KAc). The grafted acrylate PET samples exhibited contact angles of 8 ± 3° and 28 ± 13° for NaAc and KAc, respectively, while showing durability in ageing and washing tests. The dry film thicknesses for both samples were found to be 28 ± 2 μm. Finally, the anti-adhesive properties of the NaAc- and KAc-treated surfaces were evaluated using an Escherichia coli expressing YadA, an adhesive protein from Yersinia. The modified PET surfaces were highly effective in reducing bacterial adhesion by more than 90%.

(Invited) Atmospheric Pressure Plasma Treatment of Materials

Technologies based on the use of non-equilibrium plasmas have become virtually irreplaceable in diverse application fields. These range from modification/functionalization of surfaces of medical implants, production of functional thin films or nanostructured materials, light generation, environmental remediation, ozone generation or sterilization/decontamination of surfaces. However, there is a clear trend in the last few decades to substitute low-pressure plasma systems with the ones operated at atmospheric pressure. The interest in atmospheric pressure plasmas is stimulated not only by the decrease in equipment costs by avoiding expensive pumping systems of conventional low-pressure plasma devices but also by the possibility to process objects non-compatible with vacuum conditions. The latter triggered off rapid development of brand new scientific fields – plasma medicine and plasma agriculture.In this work, we briefly review the main operational principles of atmospheric pressure plasma sources, as well as the advantages/drawbacks of atmospheric plasma for a better understanding of the capabilities and limitations of the atmospheric plasma processing technology compared with conventional low-pressure plasma processing technologies. Subsequently, the possible use of two common atmospheric pressure plasma systems - dielectric barrier discharges and atmospheric pressure jets - will be demonstrated on the selected examples. The main emphasis will be given to the issues connected with the control of the wetting/drying/condensation of liquids on plasma-treated polymers, use of plasma pre-treatment on metallization of surfaces or their improved biocompatibility, application of atmospheric pressure plasma for deposition of nanostructured thin films, treatment of seeds with an aim to improve their germination, and last, but not least, the attention will also be devoted to the removal of organic deposits/contaminants, including pathogens, from different types of surfaces.

Investigation into the role of cold atmospheric plasma on the precision grinding of RB-SiC ceramic at room temperature

RB-SiC ceramic is one of the most important and useful materials as optical precision elements in many scientific research fields. In this paper, a novel cold atmospheric plasma (CAP) process via oxygen (O2), which is based on the precision grinding process in surface technology to modify at room temperature for grinding with a combination of plasma oxidation surface modification, is proposed. To identify the performance of the proposed cold atmospheric plasma process via oxygen method on the surface modification of RB-SiC ceramic fabrication of the precision grinding process, precision grinding test was conducted. To reveal the fundamental issue in the grinding of RB-SiC ceramic, surface-modified layer and mathematical model of the grinding trajectory via the point P(Ai, Aj) model analysis were conducted to investigate the effect of the composite process on grinding force and the mechanism of surface material removal in the presence of plasma oxidation. As a result of the method included the kept constant during the precision grinding of the composite process self-adaption-grinding process to avoid the deviation caused by second grinding particle entry. As a summary, we provide a significant cold atmospheric plasma-precision grinding compound process toward the establishment of the basic theory by analyzing the mechanism of the experimental test design and computation. The process and technical difficulties of RB-SiC ceramic and mechanism of surface modified layer material removal during precision grinding were solved.Graphical abstract The single-precision grinding and composite process schematic diagram process of the grinding wheel: (a) Traditional precision grinding process; (b) Cold atmospheric plasma (CAP) via oxygen (O2) based on the precision grinding process.

Removal of chemical and microbial water pollutants by cold plasma combined with Ag/TiO2-rGO nanoparticles

This study aimed to investigate the synergistic effect of the cold atmospheric plasma (CAP) and heterogeneous photocatalytic processes in an aqueous solution to enhance water purification efficacy and reduce the energy cost required by CAP. 0.1% Ag/TiO2-reduced graphene oxide (rGO) nanoparticles (NPs) photo-composite were prepared and fully characterized. Data showed that Ag nanoparticles and the rGO play an important role in increasing the efficiency of the whole treatment process and the photo-composite (0.1% Ag/TiO2-1% rGO at 400 °C) revealed the highest phenol removal rate with excellent reusability. Also, complete inactivation (~ 5log10 reduction) of both E. coli and S. aureus by NPs was observed without CAP exposure, whereas a minimal effect (0.1–0.5 log10) on viruses (Adenovirus (AdV), rotavirus, and ɸX174) was observed after 10 min incubation. Interestingly, the photocatalytic virus inactivation test was promising, as it resulted in > 4.7log10 reduction of AdV at 2 min treatment, whereas < 1log10 could be reduced using only CAP at the same treatment time. Accordingly, we believe that this work could provide new insights into how the synergy between CAP and 0.1% Ag/TiO2-1% rGO photo-composite in aqueous media imposes a great potential for environmental applications, such as water purification and microbial inactivation.

Jet shape analysis and removal function optimization of atmospheric plasma processing applied in optical fabrication

When inductively coupled plasma (ICP) is used as a machining tool, its chemical etching-based processing method has the advantage of no contact stress between the tool and the material, thus without any mechanical damage. In recent years, this issue has been widely concerned in optical fabrication. However, there are many differences between low power ICP jet and conventional ICP jet, one of which is that the former does not easily form a rotation-symmetric removal function due to its obvious pinch effect. In this research, the electromagnetism principle of the plasma pinch effect was analyzed firstly, and the jet shape under the pinch effect was classified. Then, experiment was carried out to investigate the plasma jet shape under the pure Ar and mixed gas of CF4-Ar, and the influence law of the reaction gas on the jet propagation shape was analyzed. Finally, the rotational symmetry of the removal function of plasma jet processing was optimized, and the nozzle design criteria were proposed based on pinch effect.

Combined use of ultrasound-assisted washing with in-package atmospheric cold plasma processing as a novel non-thermal hurdle technology for ready-to-eat blueberry disinfection

Ultrasound (US) has limited disinfection efficacy, and it has been recommended to combine it with chemical disinfectants during fresh produce washing. After washing and before packaging, the disinfection effect of US-assisted washing can be weakened; thus, in-package disinfection is important. As a nutritious fruit, there are no packaged blueberries can be directly eaten. Therefore, in this study, blueberry was selected as the model, and the two most commonly used disinfectants (free chlorine [FC] at 10 ppm and peracetic acid [PAA] at 80 ppm) were combined with low-frequency US (25 kHz) during washing, followed by in-package disinfection using dielectric barrier discharge cold plasma (CP). The disinfection efficacy of US-FC and US-PAA against Escherichia coli O157:H7 and Salmonella Typhimurium was significantly higher than that of US, PAA, or FC alone. The highest disinfection efficacy of CP was observed at the pulse frequency range of 400–800 Hz. For US-FC (1 min) + CP (1 min), an additional 0.86, 0.71, 0.42, and 0.29 log CFU/g of reduction for E. coli O157:H7, S. Typhimurium, aerobic mesophilic counts, and mold and yeast was achieved, respectively, compared with US-FC (2 min) alone. For US-PAA (1 min) + CP (1 min) an additional 0.71, 0.59, 0.32, and 0.21 log CFU/g of reduction was achieved for the above organisms, respectively, compared with US-PAA (2 min) alone. Quality loss (in total color difference, firmness, and anthocyanin content) was not observed after treatment with US-FC + CP, US-PAA + CP, US-FC, or US-PAA. After treatment with US-FC + CP or US-PAA + CP, the reactive oxygen species (ROS) content was significantly lower than that in the other groups, and antioxidant enzyme activity was significantly higher than that in the other groups, suggesting that in-package CP can activate the blueberry antioxidant system to scavenge ROS, thereby lowering the risk of quality loss. US-CP combination not only improves the disinfection efficacy but also lowers quality loss caused by ROS, without prolonging the processing time.

Performance of non-thermal plasma reactor for removal of organic and inorganic chemical residues in aqueous media

In this work, the performance of an atmospheric air-assisted plasma reactor was evaluated for the oxidative degradation of azo (orange G and congo red) and non-azo (crystal violet, and coomassie brilliant blue) textile dyes and removal of hardness in an aqueous medium. Dye degradation efficiency was evaluated at different applied voltages (2–6 kV), pH (2.85–11.44), and initial dye concentrations (5–25 ppm). Nearly 99% degradation efficiency (at 5 ppm concentration) could be achieved in 30 min treatment time for all dyes. Degradation efficiency showed a direct relationship with applied voltage and an inverse relationship with the initial dye concentration. Moreover, higher degradation efficiencies were observed at neutral pH than in the acidic and alkaline ranges. The pseudo-first-order kinetic model exhibited a better correlation coefficient (R2 > 0.90) in explaining the degradation kinetics of dyes. The water hardness was dropped by 55.5% after 60 min of plasma treatment. Also, the crystalline structure and morphology of water samples containing salts before and after the treatments were analyzed using XRD and SEM. The average crystalline size of untreated and plasma-treated samples is calculated to be 197.9 nm and 98.1 nm respectively. The concentration of O3, OH., H2O2, NO2− and ROS species increased linearly with increasing treatment time. The energy yield and energy consumption for degradation and water hardness removal were ∼0.016 g kW/h and ∼0.3932 g kW/h, 1.08*107 J/L, and 2.16*106 J/L respectively. Moreover, atmospheric pressure gliding arc discharge-based air plasma discharge was computationally modeled and electrical characteristics such as electron density, electric potential, electron temperature, absolute electron flux and charged species (positive and negative) density were examined at different applied voltages. Overall, the atmospheric air-assistant cold plasma process shows promising potential for the removal of chemical residues in water.

Effect of atmospheric plasma and rubbing coprocessing on liquid crystal alignment on a polyimide layer

We investigated the effect of combining a rubbing process with an atmospheric plasma process on liquid crystal (LC) alignment on a polyimide layer. When the two processes were used together, the pretilt angles of 2.150° and 2.601° were excellent than when the rubbing-only process was performed. Concerning electro-optical characteristics, the low-power driving voltage was less than 2.5 V and the effective switching voltage was more than 20% lower than for the conventional rubbing-only process. In addition, the thermal stability and alignment characteristics after treatment at 150 °C were superior to those obtained when the atmospheric plasma-only process was used. This study suggests a route to the manufacture of LC displays having better performance and efficiency than achievable with current LC alignment methods.

Synergistic effect of hybrid fillers/ polydimethylsiloxane composites on enhancing thermal conductivity

We used the atmospheric plasma process (APP) to modify the particles of spherical aluminum nitride (AlN), graphene (GN), and multi-walled carbon nanotubes (MWCNTs) in different size. Then, the modified AlN particles, GN, and MWCNTs were added in polydimethylsiloxane (PDMS) as fillers to form hybrid fillers/PDMS composites. The thermal conductivity (k) of the test samples was measured using an instrument that referred to the ASTM D5470-06 standard. Finally, at temperature of the room to 600 °C for the sample, the highest k and pure PDMS were tested by thermogravimetric analysis. The results show that the fillers have good combination and dispersion in the PDMS, which promotes the filler to be overlapped and arranged more closely, resulting in a synergistic effect and a significant increase in the k of the hybrid filler/PDMS composites. The configuration conditions of filler with the highest k are 60 wt% spherical AlN particles, 2 wt% GN, and 2 wt% MWCNTs, and its k can reach 7.02 W/m-K. Furthermore, the hybrid fillers/PDMS with the highest k prepared in this study has superior feasibility under the operating temperature range of 200 °C in addition to a superior k value.

Effect of Glow and Dielectric Barrier Discharges Plasma on Volatile and Non-volatile Chemical Profiling of Camu-Camu Juice

Nuclear magnetic resonance (NMR) is a powerful technique to characterization of taste profile based on organic compounds from foods. Likely, gas chromatography coupled to mass spectrometry (GC-MS) enables the detection of aroma profile of foodstuff. Therefore, the present study aimed to evaluate the influence of two different cold plasma processes (dielectric barrier discharge atmospheric plasma (ACP) and glow discharge plasma (GP)), as well as the effect of different processing conditions on taste and aroma profiles from camu-camu juice. Both ACP and GP processing resulted in modifications on taste and aroma, which were strongly dependent of the frequency of plasma generation, flow rate, and treatment duration. The GP processing resulted in higher influence on camu-camu composition than ACP, which decreased the contents of important flavor compounds while increasing vitamin C and ethanol contents. Moreover, GP during 10 min at 10 mL/min and 20 min at 20 mL/min of plasma flow rate did not present significant effect on the juices composition as a whole (taste and aroma related compounds). The ACP processing presented significant influence on the juices composition at 420 and 530 Hz, while 200 and 960 Hz maintained the overall organic composition. Therefore, the use of NMR and GC-MS coupled to advanced chemometric analysis (data fusion) allowed a deep understand the camu-camu chemical variability submitted to plasma technologies based on taste and aroma compounds. This information indicates that appropriate treatment conditions are important for decontamination while preserving and improving the food characteristics in order to match the consumer demands.

Surface functionalization of thermoset composite for infrared hybrid welding

Fusion assembly is a highly promising technique for joining thermoplastic composite to thermoset composites, enabling the use of both the most affordable composite material and process for each substructure. However, some major challenges need to be addressed such as functionalizing the thermoset composite surface through co-curing with an appropriate thermoplastic interlayer or realizing a fast and robust welding process that meets all quality and mechanical requirements. In this paper, we investigated the potential of polyetheretherketone (PEEK) and its amorphous (PEEK A) and semicristalline (PEEK SC) states as interlayer materials, co-cured onto thermoset composites. A surface preparation involving the atmospheric plasma process demonstrated that both PEEK state materials can be used as interlayer with favorable adhesion properties. The influence of the plasma treatment on surface properties and morphology was also experimentally characterized.