Berlin 2018 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 20: Poster Session I
CPP 20.54: Poster
Montag, 12. März 2018, 17:30–19:30, Poster A
Morphologies in liquid-liquid dewetting — •Roghayeh Shiri1, Ralf Seemann1, Dirk Peschka2, and Barbara Wagner2 — 1Experimental physics, Saarland University, Saarbrucken, Germany — 2Weierstrass Institute, Mohrenstr 39, Berlin, Germany
We study the dewetting of thin nanometric thin polystyrene (PS) films from liquid polymethyl-methacrylate (PMMA) substrates. In order to induce dewetting the PS/PMMA samples are heated above the glass transition temperature of both polymers. After a few minutes circular holes appear in the PS film and their radii grow with time and finally coalescence leading to a set of droplets on the substrate.
The considered mechanism leading to the symmetry breaking of the initially flat film is called spinodal dewetting, which is initiated due to the growth of thermally activated surface waves. The spinodal rupture of the liquid film results in a dewetting pattern of *hills and gullies* with a certain preferred wavelength λ in both liquid/air and liquid/liquid interfaces leading eventually to the formation of holes after a certain time t. Interestingly, the deformation of the liquid/liquid interface is larger than that of the liquid/air interface due to the lower surface tension. According to theoretical predictions, can the deflection of both interfaces be in phase or antiphase which determines the dewetting pathway.
In this study we experimentally measured the preferred wavelength λ and holes distance and we monitor deformation of interfaces by atomic Force Microscopy. Ultimately, the result of experimental observations will be compared with theoretical modelling.