Icing of wings and propellers is a critical problem for traffic safety in aviation (economic and safety aspect). Ice accumulation leads to airflow disturbances and reduces dynamic lift up to stall. Therefore, strategies for icing prevention and deicing have always played an essential role in the operation of aircraft in climatically critical environments. Various active systems are commercially available for deicing wing sections (mostly the leading edge). Pneumatically supplied, flexible rubber mats (boots) change the surface size when ice is detected by introducing air, thereby blasting it off. Thermal de-icing systems heat critical zones to melt the ice/surface contact zone, causing it to flow off. They are either heated electrically or, in the case of aircraft with jet engines, with bleed air from the engine. To prevent ice accumulation, active chemical anti-ice systems for the wing leading edge are offered for small aircraft. In this case, drilled surfaces at wing areas heavily affected by icing are used to pump an anti-icing fluid from the rear through these holes, thereby creating a film which is intended to prevent water from freezing. This system is currently limited for use on the leading edge of the wing. Each of these systems has disadvantages: Thermal de-icing requires a lot of energy, pneumatic systems have a negative impact on aerodynamics and chemical de-icing leads to an additional weight load and a limited duration of use. 

The aim of this project is to develop resistant, passive and passive/active anti-ice surfaces by combining several key technologies and to extend the field of application to propellers. This extension is not only relevant for manned aviation, but also for unmanned aviation (drones/multicopters). The basis for this is laser structuring using femtosecond lasers, with which it is possible to create fine nanostructures (LIPSS) on the one hand and porous microstructures on the other, which have superhydrophobic properties. In further steps, these structures are to be coated chemically and by means of plasma processes in order to make them durable and additionally ice-repellent. These passive anti-ice surfaces will also be investigated as a passive/active system. For this purpose, micro-channels will be drilled into the structured surfaces by means of lasers in such a way that they can be supplied with various anti-ice fluids from the back of the sample. Compared to existing technologically and ecologically immature systems, this research project will use passive surface modification with the latest technologies to improve the anti-icing properties and the ecological footprint by reducing/substituting glycol. Furthermore, selected anti-ice surfaces will be applied to a propeller blade and tested under dynamic conditions on the rotor test bench in the climatic wind tunnel.