Mechano-optical force sensors on a molecular scale

Dr. Robert Göstl, independent research group leader at the DWI – Leibniz-Institute for Interactive Materials, has successfully applied for a research grant from the German-Israeli Foundation for Scientific Research and Development (GIF) in the framework of the Young Scientist Program. This grant allows him to collaborate and exchange ideas with excellent researches at Israelian research institutes and universities. Göstl will also be travelling to Israel for a series of lectures this May.

Göstls field of expertise is the mechanochemistry of molecules. He analyses the impact of mechanical stress on polymers and their three-dimensional architectures. He not only examines the processes in cell-like structures, but also analyses classical materials for composites. Having a suitable tool is crucial for this research on the molecular level. Göstl applies so called molecular mechano-optical force sensors. These sensors react to mechanical stress by changing their optical properties, for example their ability to absorb or emit light.

Robert Göstl examines Diarylethene, a class of chemical molecules, whose structure changes in a light-dependent manner. Diarylethenes reversibly form colored, closed rings upon irradiation with UV light. At the same time, they change their physical and chemical properties. Göstl wants to explore how these colored, closed-ring-shaped Diarylethenes behave under applied mechanical force. He expects the ring structures to re-open under mechanical stress, thus regaining their original structure and losing their color at the same time. The color loss of the molecules would then indicate the impact of the forces applied. In principal, it would also be possible to use other, similar molecules instead of Diarylethenes. However, for Diarylethenes, both the ring- and open-ring structures are stable at room temperature which is not the case for similar molecules.

Göstl expects these modified Diarylethenes to display time-independent mechanochemical changes by modification of their color and therefore to work as force sensors on a molecular level.