Institute showcases anti-fouling coatings

 A range of anti-fouling 'tuned' films has been developed by the Fraunhofer Institute for Surface Engineering and Thin Films (IST).

The special coatings prevent proteins, salt crystals and calcium carbonate deposits from sticking to the surfaces of plants or system components.

Inventing the films was a challenge, the institute, which is based in Brunswick, Germany, said, because the types of deposits they were created to repel varied depending on the materials used to make equipment and the liquids being processed.

However, scientists at the research centre have now found a way to adapt the coatings for a wide variety of different industrial applications and loads. They have achieved this by 'custom tuning' the structures and surface energy of the coating surfaces.

Surface energy

The surface energy determines to what extent deposits are able to cake on. "The range of properties relating to these layers range from high wear protection through to an extreme anti-fouling effect," said Dr Martin Keunecke, head of department for new tribological coatings at IST.

"With the help of special process technology, we are now able to create practically any desired property."

In addition, he said he was working on internal coatings for pipes. "Now that we understand how to individually configure the layers, the next stage involves tackling the question of how 2 most efficiently produce the coated equipment.

"Anti-fouling already works extremely well for external surfaces, however, internal coating, for example, for pipes is anything but straightforward. For this reason we are now collaborating with industry and research partners to create new manufacturing processes."

Carbon layers

The coatings are made up of carbon and other elements and are just a few micrometers thick, approximately 50 times thinner than a human hair. Extremely hard wearing and durable, carbon layers are characterised by excellent anti-corrosion and anti-wear properties.

Their surface energy can be further reduced by integrating non-metallic elements such as fluorine and silicone, boosting the anti-fouling effect. "Depending on the type and quantity of the elements used, we are able to control the properties of the coatings in a targeted way," said Dr Peter-Jochen Brand, head of department for the Tribology Transfer Centre at IST.

"This is necessary because industrial plants are subjected to a wide range of differing stresses resulting from liquid substances. Just consider milk processing or fruit juice manufacturing in the foods industry ..."

Keunecke and Brand said they believed anti-fouling applications were still in their infancy, so they said they were were expecting fresh momentum from the market as a result of their innovations.

They will be showcasing their coatings and films at the Surface trade fair from April 8-12 in Hanover, Germany.