Berlin 2024 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 52: Focus Session: Wetting on Adaptive Substrates III (joint session CPP/DY/O)

DY 52.5: Vortrag

Freitag, 22. März 2024, 10:45–11:00, H 0110

Light-Triggered Manipulations of Droplets All in One: Reversible Wetting, Transport, Splitting, and Merging — •Maren Umlandt, Nino Lomadze, and Svetlana Santer — University of Potsdam, Potsdam, Germany

We report on light-triggered droplet manipulation such as reversible wetting, splitting, merging, and transport [1]. The unique feature is that the changes in the wetting properties of anisotropic liquids adsorbed on photo-switchable films can be triggered by application of optical stimuli, which lead to changes in the morphology of the surfaces. The adaptive films consist of an azobenzene-containing surfactant attached to oppositely charged polymer chains. Under exposure to irradiation with light, the azobenzene photo-isomerizes between trans- and cis-states, resulting in changes in surface energy and orientation of surfactant tails in film [2]. The increase in the surface temperature due to absorption of light by the azobenzene groups [3] enables diverse processes of droplet manipulation. Using a moving light spot, we demonstrate the locomotion of the droplet over macroscopic distances. Our findings could lead to the application of a programmable workbench for manipulating and operating an ensemble of droplets.

We thanks for funding DFG and RFBR.

[1] Umlandt, M. et al. ACS Applied Materials & Interfaces 2022 14 (36), 41412-41420 [2] Arya, P. et al. J. Chem. Phys. 2020, 152, 024904 [3] Zakharov, A. V.et al. Phys. Rev. E 2017, 96, 052705

Keywords: photoresponsive surfaces; wetting/dewetting; droplet motion; splitting/merging; azobenzene surfactant