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DY: Fachverband Dynamik und Statistische Physik

DY 9: Nonlinear dynamics, synchronization and chaos II

DY 9.3: Vortrag

Dienstag, 24. März 2009, 10:45–11:00, ZEU 255

Pattern Formation During Deformation of a Confined Viscoelastic Layer: From a Viscous Liquid to a Soft Elastic Solid. — •Julia Nase^1,2, Anke Lindner¹, and Costantino Creton² — ¹PMMH-ESPCI, Paris, France — ²PPMD-ESPCI, Paris, France

We study pattern formation during tensile deformation of confined viscoelastic layers. The use of a model system (PDMS with different degrees of crosslinking) allows us to go continuously from a viscous liquid to an elastic solid. We observe two distinct regimes of fingering instabilities: a regime called "elastic" with interfacial crack propagation where the fingering wavelength only scales with the film thickness, and a bulk regime called "viscoelastic" where the fingering instability shows a Saffman-Taylor-like behaviour. We find good quantitative agreement with theory in both cases and present a reduced parameter describing the transition between the two regimes and allowing to predict the observed patterns over the whole range of viscoelastic properties.