A Focus on our PhD Students – Svenja Pohl

Studying chemistry was not always my goal. I was interested in the natural sciences before I started my studies, but my big dream was to study medicine. Since I did not get a place at University, I started studying chemistry at Saarland University in Germany. At first, it was only planned as an intermediate step on the way to studying medicine, but then the subject fascinated me so much that I completed my Bachelor and Master degrees, and even started my PhD in 2020.

During my Bachelor thesis, I worked in the research group of Professor Guido Kickelbick on stability studies of dyes in commercial encapsulation materials for LEDs. By this time, I was fascinated by systematic and applicationoriented studies. In a student assistant position, I supported Nils Steinbrück in his research, who was at that time a PhD student in Guido Kickelbick’s group. I expanded my knowledge in the field of LED encapsulation, synthesis of hybrid materials and various characterization methods. Besides gaining technical knowledge, I was able to participate in the publication of papers, patents, and even a small TV production for a news program on local television about the research in Guido Kickelbick’s group. I completed my studies with a Master thesis on polyphenylsilsesquioxanes with thermoplastic properties. These compounds are synthesized by the sol-gel process and form so-called melting gels. The Master thesis was the basis of a publication which was recently published in Macromolecules and of which I am very proud.

About eight months ago I started my PhD in Guido Kickelbick’s research group. The topic of my thesis is again melting gels. These interesting compounds are organic-inorganic hybrid materials prepared from di- and trialkoxysilanes via a sol-gel process. At room temperature, the materials are transparent and glassy, and at elevated temperature they can be reversibly melted. If the temperature is raised further, the materials cure irreversibly. Depending on the organic substituents at the silicon atom and the composition of the alkoxysilanes, properties

such as the refractive index, hardness or viscosity can be adjusted using controlled conditions and knowledge of the reactivity of the individual components. This variation in properties, as well as their high-temperature stability, transparency, and discoloration resistance make them extremely interesting for optoelectronic applications. My goal is to synthesize melting gels with different properties by varying the monomers and to investigate the influence of the organic substituents on the structure. It is also interesting to work very closely with companies and to keep an eye on direct applications of the materials. At the same time, one can do basic research by studying the structure-property relationships and the chemical processes that occur during synthesis. This multifaceted nature makes the field very exciting and varied.

Looking back, I am very happy to have chosen the path of studying chemistry and I am excited about the experiences I will have as PhD student in the coming years.