Functional polymer materials

Tailor-made material properties with intelligent adhesives, self-healing coatings and adaptive composites

With the aim of equipping components and materials with additional functionalities, "stimuli-responsive" adhesives, self-healing paint systems or adaptive composites are being developed. Against the background of resource scarcity and increasing pollution of the environment with plastics, polymer materials based on renewable or biodegradable raw materials play a major role. For example, starch-based adhesives are being developed for wood bonding, biocomposites made from biopolymers and natural fibers for the packaging industry or agriculture, and additives made from chitosan for antifouling coatings. Carbon dioxide also plays a role as a raw material and synthesis component in order to relieve the atmosphere of this greenhouse gas. Here we present some of the research topics.

Self-healing coatings


Coatings are often exposed to extreme conditions. The combination of environmental influences, internal stresses and aging phenomena can lead to cracks in the coating, and result into damages (e. g. on ships, wind turbines). This leads to an increased need for repair and thus also to high costs. Fraunhofer IFAM is working on the development and testing of self-healing coatings. One approach pursues the goal of incorporating microencapsulated corrosion protection inhibitors into a coating. If the coating is then damaged, the microcapsules rupture at the site, the healing reagent contained flows out and hardens in the crack. In this way, cracks can be resealed, preventing crack propagation and deep corrosion damage. Another approach is to develop polymers whose molecular structure allows scratches and cracks to self-heal from the coating resin itself.

New polymeric materials: biobased and biodegradable


Companies are feeling pressure from consumers and policymakers to make their products and semi-finished products sustainable. The first step towards a better life cycle assessment is often to replace existing plastics with new polymers that are biobased and/or biodegradable. Fraunhofer IFAM often takes the approach of developing new plastics within the framework of polymer systems already used by companies. This offers the advantages that known material properties can be retained and processing procedures do not have to be changed.

Polymeric materials for medicine and medical technology


More and more polymeric materials are being used in medicine and medical technology that have to meet special requirements. These may include targeted colonization with the body's own cells, antimicrobial properties and high resistance in the biological environment. Test methods are available for this purpose in order to carry out appropriate tests in parallel with material development. These are also used to determine cell toxicity. The parallel use in material development ensures that acceptance tests are passed in a certified laboratory. In addition to the use of polymeric materials in medical instruments, those for operations and for remaining in the body are also being developed. These include, for example, an adhesive system for the residue-free removal of kidney stones, which is being brought to market by our spin-off company Purenum and adhesives for hard and soft tissue surgery. Another focus is on dental materials such as adhesives, composites or 3D printing resins. In this field, we cooperate with numerous doctors and clinics in order to ensure that our products are implemented in practice.

Polymers for the energy industry


A successful energy transition requires innovations in the field of polymeric materials, which play an important role in the generation, transport and storage of renewable energies.

In the future, hydrogen will play a key role as an energy source in the mobility industry, but also in climate-neutral energy supply. In the aerospace industry, hydrogen is usually stored in liquefied form under extremely low temperatures of -253°C. Since weight plays a decisive role in these areas, lightweight materials and in particular carbon fiber reinforced plastics (CFRP) are of particular interest as materials for tank systems. At Fraunhofer IFAM, plastics are being developed which, as lightweight materials or as special barrier coatings, enable the components to be used at extreme temperatures and ensure impermeability to the extremely small hydrogen molecule.

Green hydrogen is an important pillar for the decarbonization of heating and cooling. Organic carrier fluids LOHCs - liquid organic hydrogen carriers are being researched as an alternative for storing and transporting hydrogen. In addition to materials for new tank concepts, polymeric materials are being considered in the TransHyDE Helgoland project as adhesives, barrier layers, sealants and adhesives.

Electrical energy storage systems are indispensable in many technical fields of application. Safety and efficiency are essential factors that the materials used in batteries must meet. At Fraunhofer IFAM, polymeric materials are being researched and developed as components in solid-state batteries.