Regensburg 2025 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

CPP: Fachverband Chemische Physik und Polymerphysik

CPP 31: Responsive and Adaptive Polymers

CPP 31.4: Vortrag

Mittwoch, 19. März 2025, 17:15–17:30, H38

Chain conformation of thermo- and photo-responsive polymers — •Peiran Zhang¹, René Steinbrecher², Cy M. Jeffries³, André Laschewsky², Peter Müller-Buschbaum¹, and Christine M. Papadakis¹ — ¹TUM School of Natural Sciences, Technical University of Munich, Garching, Germany — ²Institute of Chemistry, University of Potsdam, Potsdam-Golm, Germany — ³European Molecular Biology Laboratory, DESY, Hamburg, Germany

Endowing thermoresponsive polymers with additional photoresponsivity is of interest for applications such as drug delivery and soft robotics, owing to the non-invasive nature of these stimuli and the high temporal and local resolution of the photostimulus. The lower critical solution temperature (LCST) behavior in aqueous solution, characterized by a coil-to-globule transition at the cloud point (CP), can be finely tuned by incorporating photoswitches. Among these, azobenzene (AB) is the most widely used due to its pronounced trans-cis isomerization without side reactions. However, due to the weak change of dipole moment, its influence on the CP is only small. To enhance this photo effect, we used various amino acids as flexible linkers between the thermoresponsive backbone and the AB moiety. Dynamic light scattering reveals that a higher AB content leads to a larger shift of the CP, while small-angle X-ray scattering indicates that the amino acid linker reduces the influence of the inherent rigidity of the AB side groups, making the entire polymer chain more flexible. This approach allows adjusting the CP in wide ranges of temperature, thereby enhancing the range of applications.

Keywords: stimuli-responsive polymers; small-angle X-ray scattering