The Heyn Commemorative Medal, named after the first DGM chairman Emil Heyn (1867–1922), is the highest award given by the DGM. It is awarded for achievements in the field of materials science and materials engineering that have led to significant advances in science, technology, or economics. With the Heyn Commemorative Medal 2025, the DGM honors the life's work of Prof. Dr. Jörg Weißmüller, Hamburg University of Technology.

1) You completed your doctorate under Herbert Gleiter, a pioneer in nanomaterial research. You then worked with John Cahn, one of the most important theorists in materials science. Both Gleiter and Cahn were awarded the Heyn Medal. Which experiences from working with these two influential figures had the greatest impact on your career path, either scientific or personal?

Herbert Gleiter's challenging and motivating teaching style was a highlight of my materials science studies in Saarbrücken. I got to know him as an extremely charismatic and visionary scientist. The conversations in which he recommended topics for my diploma and doctoral theses are unforgettable. I have always considered conveying motivation and enthusiasm to my colleagues to be particularly important, and Herbert Gleiter is a role model in this respect. He provided me with crucial support at several important points in my early career, opening the door to science for me. For this, I am extremely grateful.

It was a special privilege to interact with John Cahn. I consider him to be the most influential figure in materials science. I got to know him as an exceptionally warm person. The clarity, precision, and depth of his science set an unattainable standard for mortal researchers like me. My interactions with John and his colleagues during my time as a visiting scientist at NIST sparked scientific ideas that preoccupy me to this day, 30 years later. These ideas concern capillary effects, coherent equilibria, and the mysterious Cahn-Hilliard residue, for example. Material design and experiments on the elasticity of open systems, another example, play a small but important role in the recently approved BlueMat Cluster of Excellence at the Technical University of Hamburg.

2) Your working methods are described as unconventional, with a keen eye for connections that are not immediately obvious. Could you explain how you develop these new approaches and the role that intuition plays in this process, especially when it comes to new fundamental principles?

For every scientist, isn't the cardinal question, "How do I arrive at a new approach?" For me, it's a process of trial and error. I make lots of attempts on a topic and experience many failures, separated by long periods during which I occupy myself with completely different things. Finally, for no apparent reason, a good idea comes to me. Or not, depending on the topic. A decisive factor is often breaking out of the circularity of one's own thoughts during discussions with colleagues.

3) You have worked at several renowned research institutions around the world, including the CRMC² in Marseille, France; the National Institute of Standards and Technology (NIST) in Gaithersburg, Maryland, USA; the Institute for New Materials (INM) in Saarbrücken, Germany; and the Karlsruhe Research Center (KIT) in Karlsruhe, Germany. Which of these places has had the greatest personal influence on you, and why?

 As you may have noticed, these are all non-university institutions. I felt privileged to be surrounded by colleagues who were comparatively less tied up in the various tasks of the academic treadmill, making them spontaneously available for scientific discussion. After my experience with a rather hierarchical system in France as a young doctoral student, discussing things on an equal footing felt very refreshing in Germany and especially in the USA. Additionally, I had the opportunity to engage in truly inspiring conversations and experiences at all locations.

4) What advice would you give to young materials scientists aspiring to have a career as long and successful as yours? To what extent do such successes depend on chance, the right contacts, or other factors, in your experience?

Life cannot go on without chance. In my case, a permanent position opened up at the newly founded Institute for New Materials right after I finished my doctorate. That was a turning point, even though I later resigned from that position to take a riskier but more exciting temporary position. My advice to young scientists is to explore the topics you enjoy most. Enjoyment is a prerequisite for excellent science, and with that, opportunities will open up for you. Science offers the highest degree of freedom here—you can and must determine what is scientifically significant for yourself, flexibly adapting to the latest findings. Of course, you also have to consider what you can pragmatically expect to achieve and whether you can inspire your colleagues with your work.

We would like to congratulate Professor Jörg Weißmüller once again on receiving this special award. We look forward to honoring him and all of the award winners at DGM Tag 2025, where we will have the opportunity to meet them in person.