Regensburg 2022 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
CPP: Fachverband Chemische Physik und Polymerphysik
CPP 12: Poster 1
CPP 12.29: Poster
Montag, 5. September 2022, 18:00–20:00, P1
A combined experimental-theoretical study of azo-SAM restructuring under light stimulus: New insights — Alexey Kopyshev1,2, Amrita Pal1, Svetlana Santer2, and •Olga Guskova1 — 1IPF Dresden, 01069 Dresden, Germany — 2University of Potsdam, 14469 Potsdam, Germany
The topography transformation of the self-assembled (SAM) layers of azobenzene (azo) surfactant [1] on mica is studied using AFM and modeled in all-atom MD simulations. Under blue light, when azo adopts the trans-state, the smooth SAMs are formed. Under UV stimulus due to a shift in equilibrium between trans and cis isomers, a rapid change in the topography of SAMs occurs. Subsequent blue light irradiation leads to the stabilization of SAMs and smoothing of the upper layers. The explanation of the layer restructuring/mass transport is proposed in simulations. First, we observe that the cis isomers diffuse slower within the adsorbed layers. Second, the expulsion of the cis isomers from SAM is detected independently of the layer compositions. Third, the vertical diffusion for trans isomers is negligible, whereas for cis-state it is comparable to diffusion within the layer. Thus, the change in the topography of SAMs under UV light seen in AFM is related to the vertical diffusion of cis azo. The work is supported by DFG (project GU1510/5-1). [1] Titov E. et al. ChemPhotoChem 5 (2021) 926.