SKM 2021 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 3: Polymer Physics

CPP 3.7: Talk

Monday, September 27, 2021, 15:45–16:00, H3

Columnar Stacks of Azobenzene Stars Under Irradiation - Photoisomerization Kinetics and Light-Induced Defects — •Markus Koch, Marina Saphiannikova, and Olga Guskova — Institute Theory of Polymers, IPF Dresden, Germany

Azobenzenes (azo) are a class of molecules that photoisomerize between their trans and cis state, causing dramatic conformational changes. These chromophores are widely used to add light-responsive properties to various microscopic or macroscopic systems. The object of this study is a star-shaped molecule (TrisAzo) containing three azo groups connected via a BTA group. TrisAzo not only has a rich photoisomerization behavior [1]. In polar media, these molecules self-assemble into supramolecular structures, that undergo a reversible morphological transition upon UV-Vis light irradiation [2]. Our study focuses on modeling these systems via fully atomistic MD simulations. In particular, we investigate the effects of UV-Vis light on columnar TrisAzo stacks [3]. Using a detailed simulation approach, we can closely reproduce the photoisomerization kinetics in these systems. Moreover, the results demonstrate how light induces defects in the columns and how this is related to the intermolecular interactions of stacked TrisAzo molecules. We thank the German Research Foundation (DFG) for financial support, project GU 1510/5-1.

[1] M. Koch et al. J. Phys. Chem. B 121 (37), 8854-8867 (2017)

[2] S. Lee et al. Langmuir 29 (19), 5869-5877 (2013)

[3] M. Koch et al. Langmuir 35 (45), 14659-14669 (2019)