European breakthrough has potential for self-cleaning sheet metal

Taking inspiration from defence mechanisms found in plants such as the Lotus leaf, the ‘High Throughput Laser Texturing of Self-Cleaning and Antibacterial Surfaces’, or ‘TresClean’ project, harnessed new photonics technology to develop the first fluid-repellent, antibacterial, metal surface.

This new technique will initially be used to create antibacterial surfaces for use in the food production industry, an advance that is expected to increase productivity and reduce costs in factories that process biological food products.

TresClean has used high-power laser cutting devices to create a specifically tailored, rough micro-topography on sheet metal that mimics the surface of the Lotus leaf, causing liquids to be repelled from them. This roughened surface creates miniature pockets of air that minimises the contact area between the surface and a liquid.

Prof Luca Romoli, project coordinator of TresClean said: “In the same way that Lotus leaves keep themselves clean, without the need for cleaning products or chemicals, their jagged, rough surfaces enable water to stay as spherical droplets by preventing ‘spreading’.

“Bacteria do not get a chance to stick because the contact with the metal surface and the liquid is reduced by over 80 per cent. We are looking at an anti-bacterial metal”.

While this replicating approach may currently exist for specific and expensive plastic components, it is said to be a first for self-cleaning metal.

Metal surfaces are textured using innovative industrial photonics devices: high-average power ultrashort-pulsed lasers are used in combination with high-performance scanning heads by utilising a beam delivery method enabling movements of up to 200m/s.TresClean can achieve this surface texturation by cutting areas of 500 square cm in less than 30 minutes.

Prof Romoli estimates that TresClean could have its products ready within two years.

Initially aiming its product at machine parts for the food industry TresClean expected to make a positive impact on productivity.

“Vats in milk factories need to be cleaned every 6-8 hours to avoid the exponential growth of bacteria. This hinders usage and therefore affects output” Romoli said in a statement. “By saving hours per day in cleaning, it will yield an efficiency improvement stemming from fewer sterilisation cycles and less cleaning time within production as a whole. This will also reduce energy consumption as a result of fewer cleaning phases making food production quicker, safer and more profitable.”

Prof Romoli sees the long-term possibilities and implications for other sectors too.

“It is possible that any use of metal that needs to avoid the formation of bacteria will benefit from the TresClean product, such as medical cutting tools, sterile surfaces, dishwashers, or even saucepans.”

Coordinated by the Universitá Degli Studi Di Parma, the consortium includes members from Italy, France, Germany, Spain and the UK and has received a grant of €3,363,091.25 from the Photonics Public Private Partnership under the H2020 Industrial Leadership funding calls.