Hugo Geiger Prize 2024

The Bavarian Ministry of Economic Affairs, Regional Development and Energy (StMWi) and the Fraunhofer-Gesellschaft awarded the Hugo Geiger Prize for the best dissertations in applied research to three next-generation researchers, one each from Freising, Munich and Aachen. The winners were chosen for their innovative ideas and applied doctoral work completed in close collaboration with a Fraunhofer institute. The Fraunhofer Founder Award was also presented for a spin-off with an active, successful market presence.

Thermoformable plastic alternative made from cellulose

Over 90 percent of the 414 million metric tons of plastic produced worldwide in 2023 originated with fossil raw materials. Bio-based plastics made from plants like corn or wood account for just 0.7 percent of production volume, as their material properties are inferior to those of conventional plastics. The chemical processes used to improve flexibility often cause the natural structure of the cellulose to be lost, which also impairs biodegradability. Dr. Kerstin Müller developed a physical approach to make thermoformable plastic out of plant-derived cellulose. Müller uses polylactic acid molecules to create more space and flexibility between the cellulose molecules. To do this, she dissolves the cellulose in an ionic liquid and binds the molecules with those in polylactic acid. As part of her dissertation, Müller also translated her method into an industrial process, demonstrating its practical applicability. The thermoformable and biodegradable new material is suitable for uses including products in the agricultural sector, such as tube-style tree protectors or planters.

Slurry-based 3D-printing of ceramic casting cores

In casting technology, 3D printing of sand cores is already part of mass production, where it is used to produce increasingly complex components for uses in fields such as aerospace and medical engineering. During the process of casting in molten metal, the casting cores model the internal cavities inside cast components. They are mechanically removed once the casting is complete. The issue is that these increasingly intricate cores need to withstand the heavy mechanical and thermal stresses arising during the process. For her doctorate, Dr. Patricia Erhard advanced the methods used for 3D printing of casting cores: Instead of sand, she uses a ceramic suspension that allows for finer surface structures, greater temperature stability and high strength during the subsequent sintering process. This opens up new possibilities for the design of intricate interior structures in cast components. To mechanically remove the cast cores in the end, Erhard built snap-off points into the inside that destroy the core as it cools.

Next step in the evolution of high-performance fiber lasers and laser diodes

From the energy sector to medical engineering, the semiconductor industry and telecommunications, lasers are an integral part of many technologies today. The goal of Dr. Sarah Klein’s doctoral work was to increase the efficiency and durability of high-performance fiber lasers and laser diodes used in industrial applications such as welding and medical processes and make them less susceptible to errors. To do this, she incorporated the resonator mirrors for the fiber lasers, which amplify the radiation, directly into the fiber. This is made possible through the use of fiber Bragg gratings (FBGs). This approach simplifies the structure and increases robustness. Previously, the mirrors were attached externally and required laborious and time-consuming adjustment. Klein also studied frequency stabilization of laser diodes with an eye to harnessing their power more efficiently. New FBG techniques can reduce spectral emission bandwidth, thereby increasing the lasers’ brilliance. The findings from her dissertation will contribute to innovative fiber and diode lasers that can be used more efficiently and with greater versatility across a range of industries and in future technologies such as laser-based inertial fusion.