Microwave Air Jet Plasma

It is used for efficient processing, heating, drying or material transformation.

High efficiency, process reliability and complete customization.

Yes, Kerone offers fully customized engineering solutions.

Food, chemical, pharma, biomass, rubber, textile and more.

Kerone ensures high product quality through strict engineering standards, advanced testing procedures, and precision-controlled manufacturing systems.

The reactive species in plasma modify surface chemistry by creating polar functional groups (hydroxyl, carbonyl, amine groups) that significantly increase surface energy and improve wetting and adhesion.

Yes, the combination of reactive oxygen and nitrogen species, UV radiation, and charged particles in the plasma effectively inactivates bacteria, viruses, fungi, and spores on surfaces.

Yes, Kerone offers automated scanning plasma systems that can be integrated in line with packaging, printing, bonding, and manufacturing production lines.

A microwave air jet plasma generates a complex mixture of excited oxygen and nitrogen species, ozone, hydroxyl radicals, and ultraviolet photons, collectively referred to as reactive oxygen and nitrogen species (RONS). These species interact with a material's surface by breaking and reforming surface chemical bonds, introducing polar functional groups, and in some cases etching a thin top layer of organic contamination. The specific mix of species generated depends on gas composition, flow rate, and microwave power, which is why Kerone's systems offer tunable gas and power settings to match the reactive chemistry to the target material and desired surface modification outcome.

Surface activation typically increases rapidly during the first few seconds of plasma exposure as reactive species saturate available bonding sites, then the rate of additional improvement slows as the surface approaches a chemically modified equilibrium state. Excessive treatment time can sometimes degrade results by over-etching the surface or generating low molecular weight oxidized material that can migrate back to the surface and reduce adhesion performance, an effect sometimes called weak boundary layer formation. Optimal treatment time is therefore material-specific and is typically determined through trial runs measuring surface energy or contact angle at several exposure durations before settling on a production parameter.

Yes, plasma treatment is frequently used as one stage within a multi-step surface preparation sequence rather than as a standalone process. It is commonly positioned immediately before printing, coating, or bonding operations since plasma-activated surfaces have a limited window before surface energy begins to decay back toward baseline, particularly on polymer substrates. Combining plasma activation with mechanical cleaning or solvent wiping beforehand removes gross contamination that plasma alone is not designed to handle, while the plasma step then provides the final chemical activation needed for strong adhesion in the downstream process.

Effective treatment distance depends on the specific plasma jet design, but most atmospheric microwave plasma jets operate with the plasma plume contacting or positioned within a few millimeters to a few centimeters of the substrate surface, since plasma reactive species recombine and lose effectiveness as distance from the source increases. Line speed compatibility depends on the required treatment dose, meaning higher line speeds may need multiple plasma heads or increased power to deliver equivalent surface activation within the shorter dwell time. Kerone configures jet spacing, scanning pattern, and power settings based on the target line speed and substrate width during system design.

Vegetative bacteria and many viruses are generally inactivated relatively quickly by plasma exposure because reactive oxygen species and UV radiation readily damage their cell membranes and genetic material. Bacterial spores and certain fungal structures are more resistant due to protective protein coats and reduced water content, typically requiring longer exposure times or higher reactive species concentration to achieve the same log-reduction in viable organisms. Validation of any plasma sterilisation process should include challenge testing with the specific organism types relevant to the application, since claiming broad-spectrum effectiveness without species-specific validation data would not meet most regulatory expectations.

The primary maintenance items are the microwave generator and the gas delivery and nozzle components that direct the plasma jet toward the substrate. Nozzle and waveguide surfaces should be periodically inspected for any deposit buildup from the process atmosphere, since contamination at the plasma exit point can distort the jet shape and reduce treatment uniformity. Gas flow controllers and filters require routine calibration checks to ensure consistent gas composition reaches the plasma zone, since drift in flow rate directly affects reactive species concentration and therefore treatment effectiveness on the production line.

Beyond the well-established polymer film and packaging adhesion market, microwave air jet plasma is increasingly used in biomedical device surface preparation, textile finishing for improved dye uptake and water repellency, and electronics manufacturing for fine cleaning of circuit boards before soldering or encapsulation. Food contact surface decontamination is another emerging area, where the chemical-free nature of plasma treatment is attractive compared to wet chemical sanitizers. Each of these applications requires its own validation of treatment parameters, since the target surface chemistry and acceptable processing window differ significantly between, for example, a medical implant surface and a food packaging film.