The physical and chemical principles of the process of polymeric material surface layer (WW) modification using corona discharge (WK) in an air were discussed. The phenomenon of low temperature plasma formation and the way of its interaction with polymer surface were described. Basic aims of the process of modification with WK were presented as well as the results obtained this way for particular polymers, among others PE, PP, PVC, PET. In case of PE and PP also the composite materials with polyolefine matrix or fiber filler were considered. The possibilities of corona discharge use in graft polymerization were noticed. Also numerous directions of practical use of the changes of polymers' surface layers caused by corona discharge were marked.

Plasticizer migration from plastics, particularly in polar polymers like flexible PVC, poses significant health risks, including endocrine disruption and carcinogenicity. This review article consolidates research on surface modification techniques aimed at suppressing plasticizer migration, which are crucial for minimizing health and environmental hazards. Over the past decade, substantial advancements have been made in this field. Physical irradiation methods, including plasma, ultraviolet, and gamma-ray irradiation—induce surface cross-linking, forming a three-dimensional network that reduces plasticizer migration by up to 80 %, as demonstrated by DEHP loss decreasing from 5.6 to 1.2 mg/cm2 in modified PVC. Chemical grafting techniques covalently attach hydrophilic groups or polymer chains, which interact with plasticizers via hydrogen bonding and van der Waals forces, achieving a 75 % reduction in migration, for example, DEHP leaching from 250 mg to 52 mg. Solution coating methods, particularly protein-based coatings, show exceptional performance with up to 93 % inhibition, reducing DEHP migration from 60 ppm to 4.2 ppm. Despite these achievements, challenges persist in enhancing coating durability, reducing costs, and minimizing environmental risks. Future research directions should focus on improving the long-term stability of coatings, refining experimental methodologies, and establishing robust evaluation standards. This work aims to provide a critical reference for the development of safer plastic applications in healthcare and food packaging industries, offering insights into the design and implementation of effective surface modification strategies to address the ongoing issue of plasticizer migration in plastic materials.

Corona treatment is an essential process used in the flexible packaging industry to improve adhesion on low surface-energy polymers. This paper explores how corona treatment prepares polymers for adhesion, how surface energy correlates to a good bond, forms of measurement and common pitfalls to avoid. By understanding the function of corona treatment and the science of the bond, converters can achieve consistent adhesion in printing, coating and laminating applications.

Polyolefins are widely employed as external skins for flexible packaging, yet their nonpolar, hydrophobic surfaces present challenges for high-resolution, wear-resistant printing. Converters have traditionally relied on surface treatments, such as corona treatment, to increase surface free energy (SFE) and promote compatibility with solvent-based inks. While water-based inks offer sustainability advantages and reduced volatile organic compound exposure over solvent-based inks, their adhesion to polymer substrates is inconsistent and generally not robust. Industry guidelines suggest SFE differentials between ink and substrate are the only factor influencing adhesion; however, this factor may not completely describe the ink-substrate interactions. The adhesion performance of water-based inks was evaluated on polyethylene, ethylene acrylic acid copolymer, ethylene vinyl alcohol copolymer, and polyamide. Polymer films were examined pre- and post-corona treatment to assess changes in surface energy, chemistry, and topography on ink printability and durability. To achieve acceptable print durability, these polymers all required corona treatment, leading to chemical and morphological modifications to the film surface. Results demonstrated that surface chemistry and topography are stronger indicators of water-based ink adhesion than SFE alone. These findings establish a framework for optimizing the durability of water-based inks on polyolefins and related substrates through targeted surface treatment strategies.

Corona treatment is commonly used in industry to enhance the surface-free energy of plastic films. However, corona treatment may cause some undesirable effects affecting further processing, such as sealing. In this paper, we deeply analyze the corona treatment effect on selected properties of various polymer films commonly used in packaging applications. The films were treated at two power levels (100 W and 300 W), and the experimental design included surface characterization and mechanical testing to assess changes in wettability, chemical structure, and seal strength. The Owens–Wendt approach confirmed the corona treatment effect by static contact angle measurement and surface free energy calculation. Next, their seal strength was evaluated in relation to surface energy and chemical structure changes. FTIR spectroscopy was used to identify functional groups potentially affected by corona treatment. The results indicate that the impact of corona treatment is material-dependent. In general, corona treatment at a lower level increases the seal strength, while corona treatment at a higher power level is related to a decrease in seal strength. The study highlights the importance of optimizing corona treatment parameters for specific materials to enhance seal performance without compromising surface integrity.

This is all about dynes. The dyne level of a material is called its surface energy. If the liquid has a dyne level lower than the material's surface energy, then the liquid will spread out over its entire surface in a uniform wet layer. If the ink's dyne level is equal to or higher than a material's dyne level, the liquid will become cohesive and tend to remain in droplets. So, dyne level refers to the measurement of surface energy of a material or substrate and can be a good indicator of our chances for successful adhesion. Different chemistries of adhesives are required for bonding substrates depending on their dyne level which is evident when applying a coating to a paper based product versus plastic or glass. Coatings on some materials might adhere quickly or beadup like water on glass if not compatible. Typically, lower dyne levels of 30 or less indicate that a liquid adhesive would bead-up on the surface, compared to higher dyne levels of 38 or more which indicate reasonable bonding properties. While this is one indicator of successful bonding compatibility, it does not guarantee reliable surface adhesion. But there are different means to improve adhesion based on surface preparation, improved adhesives or a combination of both.

The popularity of surface engineering has increased significantly over the past 10 years. This is usually owed to the fact that, in many instances, no more can be done to improve a material's adhesion performance through manipulation of the bulk material. Due to this, many industrialists and academics are turning their attentions to controlling material surfaces to optimize their properties, including wettability and adhesion. With its numerous benefits, when it comes to materials processing, laser surface engineering is now becoming more widely used to bring about the necessary required surface modifications for a wide range of applications such as biomedical, microbiological, tooling, battery development and for applications in the electronics industry. This Chapter discusses the implementation of lasers for the surface engineering of polymeric materials along with contact angle goniometry and tensiometry, two common methods for analysis of the wettability and adhesion of materials that will lead to the unlocking of new knowledge about wetting and adhesion regimes.

Polymers are widely used in different industries ranging from microelectronics, medical, to space. However, polymer materials are seldom used in their pristine state and need selective surface treatment to induce a specific response which is a challenging and complex task. Adhesion enhancement of polymers is one of the major requirements that can be achieved with ion beam technology at low cost. Surface enhancement involves keeping the bulk properties of materials unchanged and modifying only the surface properties to achieve optimum results. In this chapter, we illustrate the use of ion beam technology to modify the surface properties of polymers for potential biomedical and microelectronics applications. This chapter focuses on effects on the adhesion characteristics of different polymeric materials with various optimizable parameters such as type of ion used, ion energy regime (low to medium to high) and the ion fluence range with respect to singly and multi-charged ion beams.

The surface treatment of plastics as well as metals or ceramics includes a thorough surface cleaning as an essential step prior to adhesive bonding and coating processes. Besides this, surface activation of polymers is often needed because their surface free energy is too low for durable adhesion of a coating or adhesive. In this chapter various types of UV/Ozone sources with different light spectra as well as the influences of spectra and ozone concentration are investigated and compared. Also the surface wetting and adhesive bond strength as a result of UV/Ozone, atmospheric plasma, or corona treatments on thermoset, thermoplastic, and rubber materials are presented. UV/Ozone treatment was found to show an excellent cleaning performance on all kinds of materials, and especially as a very useful technique for surface functionalisation of polymers, resulting in durable adhesion both for adhesives as well as coatings. This chapter is a condensed overview of over 30 years of experiments done with UV/Ozone treatments at The Delft University of Technology.

Adhesion promotion techniques have wide applications in numerous industries for a wide range of plastic parts, and polyolefin films such as those made of PE, PP, and PET. One method used to modify the surface of these and other polymer products to promote adhesion of inks, coatings, adhesives, metallized paper and films, microorganisms or cells is flame plasma treatment. In addition, flame plasma is used to clean the surface of metals and to roughen the surface of paperboard to enhance adhesion of the polyolefin coating. This chapter describes the theory behind hydrocarbon fired flame plasma surface treatment to promote adhesion of water-based inks, coatings, adhesives, labels and other laminates to polyolefin-based substrates. Critical parameters in flame plasma treatment are flame chemistry, flame geometry, plasma output, and distance of the burner from the part. The interrelationship between these variables, and how to control them for optimum surface treatment, are discussed. A completely new patented process design has been developed and successfully implemented providing significantly improved control of the flame chemistry, while at the same time simplifying the process control and mechanical hardware required. In addition, the new design improves the overall efficiency of the flame plasma treatment process by more accurately controlling air/gas chemistry, simplifying the control valve piping, incorporating a variable frequency drive (VFD) combustion air blower to more accurately control and vary the burner firing rate, i.e., amount of plasma generated, and refining the control algorithms.

In this chapter, we present an overview on recent research and development work in the area of atmospheric pressure plasma treatments (APPTs) to generate adhesion-promoting surfaces of polymers used in various applications in automotive, aerospace, packaging, and medical fields. In comparison to the classical “corona treatment” the APPTs provide access to a broader range of industrially interesting surface modifications that are normally better controlled with respect to their physicochemical nature. Thus, application of APPTs may become a superior option for preparing polymer surfaces for adhesive bonding, adhesive-free low-temperature bonding involving homogeneous and heterogeneous substrates, lacquering, or coupling of specific biomolecules, proteins, or cells. APPT technology is, however, not only flexible for tuning surface chemistry but also is flexible with respect to plasma source and equipment design. Versatility of the APPT technology facilitates its integration into a variety of process chains. An example presented here is a hybrid technology combining both APPT and additive manufacturing based on 3D printing processes using fused filament deposition. Inline treatment by quasi-simultaneous execution of printing and APPT can, for instance, increase the adhesion of 3D printed products in print direction (z-Axis) and thus increase the mechanical stability of the printed part. In the medical field such a technology may be attractive for cell growth by promoting treatment of internal surfaces of printed porous scaffolds. In future, products made from biobased or recycled polymers will become increasingly important. APPT technology could become an important enabler for meeting the technical requirements for the adhesion of such products.

Polymers offer a wide range of bulk physical, chemical and mechanical properties, are inexpensive and are relatively easy to synthesize. However, very often these polymer surfaces do not possess properties needed for application in certain external environments which could be one of the limiting factors in their usage. Polymer surface characterization and modification is of fundamental importance for the good functioning of a composite material and plays a key role in determining successful implementation of the polymer. Tailoring of polymer surface properties such as adhesion, wettability, surface roughness and chemical reliability (including heat-soak) is critical for several applications like decorative coatings, protective films, thin film technologies and biomaterials, to name a few. For these reasons, surface modification techniques which can transform these inexpensive materials into highly valuable finished products have become an important part of the polymer and nanocomposite industries. This chapter reviews the importance and applications of polymer surface modification using corona treatment to enhance adhesion by reporting most recent advancements in the field. Novel corona treatment (type of plasma, pressure, and power) and its potential in several applications is briefly discussed in latter part of this chapter.

Surface modification to improve the adhesion property by means of dry methods such as flame, corona and plasma treatments is commonly used for films, foils and paper-based substrates. The corona discharge treatment technology is explored here and elaborated on. Subjecting the substrate to a corona discharge may provide greater wettability, higher surface free energy, and higher adhesion performance due to the introduction of polar functional groups at the uppermost surface. In addition, the surface roughness of polymeric materials may also be altered during the bombardment by the species in the discharge. The applied corona dosage, or referred to as watt density in the industry, also plays a great role in the level of surface modification.

Surface or interfacial phenomena, including wetting, adsorption, adhesion, and dissolution, are of significant interest for daily life as well as for industrial and engineering applications. Surface tension and the Hansen solubility parameter (HSP) both represent similar physical characteristics related to these phenomena. It is therefore interesting to study the relation between them, and in the present work, reported empirical relations between surface tension and HSP are critically investigated. There exists an approximately proportional relation between total surface tension and HSP, although the coefficient obtained in the present work is much smaller than the commonly reported ones. The result is supported by an estimation of the coefficient using a simple physical model. On the other hand, finding correlations between the partial components of surface tension and HSP appears to be difficult as they are measured differently. The uses of databases from which measurements are taken must also be taken into question. As an example, the surface tension components of diiodomethane are investigated, and the validity of the reported values are called into question.