Stephan Milles has spent the past two years working on creating a surface structure for the industrially important material aluminum that repels every last drop of water and also greatly delays ice formation. "When a plane flies through clouds, there's a lot to be gained from delaying the process of ice forming on wings, engines and sensor components, even by a few seconds," Milles says. Besides aviation, the aluminum rotor blades on wind turbines, tanks containing liquids in the food industry and measuring instruments also stand to benefit from the 28-year-old researcher's development, which could offer an exciting alternative to existing composite materials and surface coatings. His innovation would do away with the need for any additional chemicals or clean room conditions for texturing the surfaces of materials used in industrial applications.
Milles emphasizes: "The fact that a surface is water-repellent doesn’t mean it will also hinder ice formation - but my structure does both!" Milles points out he's the first to use a special laser-based process to etch a complex micro- and nanostructured texture to achieve the highly sought-after lotus effect. "The main challenge was to start by identifying a structure ten times smaller than a human hair and then etching this even more finely," he explains. Right now, he's working on finding a way of processing large sheets of aluminum cost-effectively: "It takes a laser interference process to finely engrave different surfaces at high speed. A square meter of aluminum will need to be etched in a matter of minutes to make the process viable for industrial use. Other methods would currently take several hours - and, even then, wouldn't create the required micro- and nanometer-sized structure."
Milles is conducting this research into the "fabrication of large areas of two- and three-level multiscaled textures with multifunctional surface properties using laser-based methods" for his doctoral thesis, supervised by the laser expert Prof. Andrés Fabián Lasagni and with the aid of funding from the German Research Foundation (DFG) as part of the Reinhart Koselleck Project. He has already received an award for his groundbreaking work at this year's International Conference on Nature Inspired Surface Engineering in New Jersey, United States, in June.
Technische Universität Dresden| Faculty of Mechanical Science and Engineering (01062 Dresden, Germany)