Dresden 2026 – wissenschaftliches Programm
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DY: Fachverband Dynamik und Statistische Physik
DY 11: Wetting, Fluidics and Liquids at Interfaces and Surfaces II (joint session CPP/DY)
DY 11.4: Vortrag
Montag, 9. März 2026, 12:15–12:30, ZEU/0260
Equilibrium droplets on deformable substrates exhibit cloaking and demixing at the three-phase contact line — •Khalil Remini1, Ralf Seemann1, Dirk Peschka2, and Barbara Wagner2 — 1Universität des Saarlandes — 2Weierstrass Institute for Applied Analysis and Stochastics
This work examines the equilibrium shape of liquid droplets on viscoelastic PDMS substrates with varying elasticities. By combining atomic force microscopy (AFM) with an initial lift-off step, we reveal not only the top contour of the droplets but also the buried droplet*substrate interface. A second lift-off step provides additional structural details near the three-phase contact line (TPCL), where the interfacial tensions adopt a Neumann balance. Quantitative analysis of the reconstructed 3D droplet shapes shows that non-crosslinked, liquid PDMS molecules are extracted from the elastic network under stress and accumulate as a liquid rim around the droplet base, thereby altering both the droplet shape and the substrate profile close to the TPCL. These liquid molecules also cloak the droplets with a thin film, modifying the effective surface tensions. Furthermore, dewetting experiments demonstrate that this demixed liquid already appears at an early stage of dewetting and remains at an approximately constant amount throughout the process.
Keywords: Sessile droplets; Cloaking; Demixing; Atomic force microscopy; Polydimethylsiloxane