Dresden 2020 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 88: Responsive and Adaptive Systems

CPP 88.2: Talk

Thursday, March 19, 2020, 09:45–10:00, ZEU 114

Deformation of Azo-Polymer Droplets by Light: Modeling the Effects of Light on Glassy Azobenzene Materials — •Markus Koch, Marina Saphiannikova, and Olga Guskova — Institute Theory of Polymers, IPF Dresden, Germany

Azobenzene (azo) is the most widespread light-responsive molecule due to its well-studied trans-cis photoisomerization mechanism. This compound has gained prominence due to the possibility to create surface relief gratings in azo-polymer materials using light interference patterns. However, it remains an open question how light induces mechanical stresses in the material. To study this process we consider a model system: a droplet composed of PMMA with azobenzene side chains, exposed to linearly polarized UV-Vis light. Experiments demonstrate, that such droplets deform along the polarization direction [1]. Here, using all-atom MD simulations two different approaches are applied: In the first case, the angle-dependent photoisomerization of azobenzene is simulated explicitly. In the second case, an effective orientation potential acts on the azo groups [2]. We demonstrate that both approaches lead to the reorientation of azobenzene in the polymer matrix and discuss the induced deformation of the droplet.

We thank the German Research Foundation (DFG) for financial support, project GU 1510/3-1.

[1] Loebner, S. et al., J. Phys. Chem. B, 122 (6), 2001-2009 (2018)

[2] Toshchevikov, V. et al. J. Phys. Chem. Lett., 8 (5), 1094-1098 (2017)