Coatings

Functional surfaces through modification, functionalization and coatings

Functional surfaces provide products and materials from a wide range of technical fields with new properties. Some important properties of materials, e.g. wettability, adhesiveness, biocompatibility, adhesion properties or tribological properties, depend only on the chemistry and topography of its surface. Other important material characteristics such as mechanical properties or processability are determined by the material used. By appropriate surface modifications, it is possible to obtain materials with a new property profile and thus to enable new applications.

We equip surfaces of plastics, ceramics or metals with new properties by applying thin layers or generating defined functions on its surfaces and develop functional coatings with e.g. non-stick and antimicrobial properties, barrier coatings, biocompatible and bioactive surfaces and functional sensor coatings.

Wide range of surface modificiation and coating technologies

For this, we use variousgas phase processes (plasma, PVD, CVD processes), wet-chemical processes (dipping, blade coating, spraying, spin coating) and combined processes – from laboratory to pilot scale.

Offer from process to sample coating

For all coatings we offer the development of a complete process – from the coating, process development and scaling up to the sample coating. We will be pleased to make you an individual offer.

  • Hydrophobic/Hydrophilic
  • Biobased coatings
  • Photocatalytic activity
  • Sensor coatings
  • Anti-icing coatings
  • Anti-stick coatings
  • Anti-scratch/anti-wear
  • Antimicrobial/antifouling
  • Barrier
  • Adhesion promoter/interlayer/bonding
  • Metallization of surfaces
  • Friction reducing
  • Biologization for improved cell adhesion
  • Drug release
  • Therapeutic coatings
  • Anti-fogging

Functions

 

Anti-ice coatings

Plasma coatings, embossed or printed structures can be used to protect surfaces against ice formation. Examples of applications include aircraft wings or wind turbine rotor blades protected against icing. The IGB has also developed an easy-to-use self-adhesive anti-icing film.

 

Hydrophobic finish with biobased chitosan

At Fraunhofer IGB, we have developed chitosan-based water-repellent finishes that could replace PFAS finishes in the leisure textiles sector in the future. The technology has already been implemented on a larger scale and the coatings are also transferable to other materials, e.g. cardboard and paper.

 

Anti-fogging

Functional anti-fogging coatings using low-pressure plasma processes can be used to prevent a disturbing visual impression caused by condensation of water droplets. The deposition can be done on flat substrates as well as on 3D parts.

 

Barrier layers

At Fraunhofer IGB, we produce barrier layers that enhance the barrier effect of the plastic polyethylene terephthalate (PET) against water vapor and oxygen by a factor of more than 1000 compared to the untreated material.

 

Dehesive layers for improved removal of residual contents from packaging systems

In most cases, fluid products such as food or personal care products cannot be completely removed from their packaging. At Fraunhofer IGB, we develop surface modifications for packaging materials that reduce the adhesion of filling goods.

 

Wettability of biomaterials: Hydrophilization of hard contact lenses

The surface of contact lenses can be modified in order to achieve improved comfort and an almost closed film of lachrymal fluid can form. At the same time the formation of protein-containing deposits is reduced. The procedure can be transferred to all polymer surfaces requiring good wettability which come into contact with body fluids, such as stents and catheters.

 

Antimicrobial coatings

To prevent biofilm formation, we are investigating the effect of naturally occurring antimicrobially active compounds such as plant extracts, cationic peptides and enzymes. We develop coating systems for long-term and targeted release and, especially in the case of biomolecules, for preserving their function over a longer period of time.

 

 

Biologization of surfaces for improved cell adhesion

The colonization of surfaces with biological cells is important in cell culture technology or for the ingrowth of prosthetic implants. We develop strategies for the biologization of surfaces and modify biopolymers such as heparin, gelatine, hyaluronic acid so that they bind covalently or adsorptively to plastic or metal surfaces.

Another topic is to avoid uncontrolled protein adsorption.

 

Improved wound healing

We develop surface modifications or formulations to positively influence wound healing after skin injuries. By binding amino groups, surfaces are modified in such a way that primary human skin cells adhere and grow better. In addition, particle-based formulations can help to release active ingredients in wound dressings.

 

Improved adhesion properties

The adhesion between the substrate and an overlying layer plays a decisive role in bonding, printing and coatings such as painting and metallization. Several factors influence the adhesion properties and minimal surface contamination can drastically reduce adhesion values. In order to achieve good adhesion performance, the pre-treatment of surfaces using plasma technology proved to be an alternative to conventional procedures.

Materials/Substrates

 

Parylene coatings

We achieve friction-reducing and chemical-resistant finishes with parylene coatings. Poly(para-xylylene), or parylene for short, is produced in a vacuum using a CVD process. Parylene can be used to coat a wide variety of substrate materials: from metals, plastics and elastomers to plants, insects and archaeological artifacts. As the process is characterized by excellent gap mobility, porous substrates such as paper and membranes can also be coated.



 

PFAS substitution via new materials and coatings

With our expertise in polymers, surfaces and coating technologies, we offer customers solutions that can be implemented quickly for the substitution of PFAS. Examples include hydrophobic finishes with non-stick plasma polymers as well as friction-reducing and chemical-resistant finishes (parylene, hydrocarbon/silicon organic-based plasma coatings).

 

Hydrophobic finish with biobased chitosan

At Fraunhofer IGB, we have developed chitosan-based water-repellent finishes that could replace PFAS finishes in the leisure textiles sector in the future. The technology has already been implemented on a larger scale and the coatings are also transferable to other materials, e.g. cardboard and paper.

 

Plasma finishing of foils and textiles

The application areas of films for packaging or surface protection bring with them a great need for customized surface finishes. These include coatings with gas permeation barriers, but also the chemical finishing of surfaces to adjust wetting properties or bondability.

 

Coatings for gas /
liquids sensors

We develop selective coatings for gas sensors to selectively detect different gases and substances:

  • Environmental gases (NOx, SO2)
  • Volatile organic compounds (VOCs)
  • Other difficult to measure molecules

 

 

Coatings for biosensors and arrays

We functionalize the surface of biosensors for the detection of biological components:

  • Biochips / microarrays
  • Immustick
  • RiFS

Technologies for modification and coating of surfaces

At Fraunhofer IGB, we use a wide range of different methods for modifying and coating surfaces. Our processes include various coating methods from the gas phase (plasma processes, PVD, CVD processes) and liquid phase (dipping, blade coating, spraying, spin coating) – from laboratory to pilot scale.

 

Process and plant development

The many issues for which coating processes are developed at Fraunhofer IGB are not limited to small laboratory systems. Thanks to the good instrumental equipment, scaling concepts such as continuous treatment of fiber and roll goods can also be implemented.

Our coating technologies

Wet-chemical processes

Wet-chemical processes are based on the fact that the molecules used for coating are applied from a liquid solvent.

At Fraunhofer IGB, we use processes such as dipping, doctoring, spraying and spin-coating for coating from the liquid phase.

Processes from the gas phase: PVD, CVD

PVD – Physical vapor deposition

PVD stands for a range of methods for thin film deposition. Atoms or molecules of the material to be deposited are transferred to the substrate via a vacuum without chemical transformation.

CVD – Chemical vapor deposition

Here we have developed a CVD process for parylene coating. Coatings from a few 100 nm to a few 10 µm can be produced. 

 

Gas phase processes: plasma technology

Stent coating in plasma.
Stent coating in plasma.

Plasma technology represents a focal point of our coating processes from the gas phase.  Plasma processing is nowadays one of the most important tools in thin film and surface treatment technologies, and thus plays a key role in manufacturing of many innovative products. The used plasmas are low temperature, low-to-medium pressure ones, enabling a gentle and controlled surface processing.

Versatile plasma technology

This way we are able to etch surfaces, e.g. to clean them, or to graft new chemical functionalities onto the surface. It is also possible to polymerize a thin film onto the surface, providing such functions as as scratch-resistance, dirt-repellency, or corrosion protection. By controlling the gas composition, power and other process parameters, a broad spectrum of chemical, physical and biological surface modifications is attainable.

Thanks to their effects, we have also developed effective processes for the plasma treatment of water with micropollutants and for the cleaning and disinfection of surfaces and even for the preservation of cultural assets.

Equipment

  • Diverse PECVD plants
  • Parylene coating plant
  • Magnetron sputtering system
  • Dip coater
  • Spin coater
  • Devices for spray coating
  • Polymer and particle analysis methods
  • Surface analytics

Services

  • Development of coatings and surface functionalizations on custom materials and geometries
  • Analysis of coatings and surfaces

Roll-to-roll processes: R2R coating and structuring

roll-to-roll coating
© Fraunhofer IGB
Roll-to-roll coating of films.

For coating and surface functionalization of web materials such as foils and textiles, at Fraunhofer IGB we use plasma, wet-chemical and combined processes. Applying our V340-GKM system from PINK GmbH Thermosysteme, for example, we carry out R2R sample coatings with up to 430 mm external width on behalf of our customers.

Furthermore, the R2R coating of e.g. foils can be combined with additional structuring via hot embossing processes. We would be pleased to discuss with you on site how we can also realize your desired coating.

Our focus

  • Barrier coatings (oxygen, water vapor, oil barrier)
  • Protective coatings (hydro-/oleophobic, anti-fog, dirt-repellent, anti-corrosive, scratch-resistant)
  •  Self-adhesive anti-ice film

Process development

For R2R coating of web material, we use plasma, wet-chemical and combined processes. With our V340-GKM system from PINK GmbH Thermosysteme, for example, we carry out R2R sample coatings with an outer width of up to 430 mm on behalf of customers.

 

 

Furthermore, the R2R coating of e.g. foils can be combined with additional R2R structuring via hot embossing.