Berlin 2012 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 13: Poster: Interfaces and Thin Films

CPP 13.11: Poster

Tuesday, March 27, 2012, 18:15–20:45, Poster A

Deformation and Buckling of Elastic Capsules — •Sebastian Knoche and Jan Kierfeld — TU Dortmund

We investigate the deformation behavior of soft elastic capsules. Based on nonlinear shell theory, a theoretical model for liquid filled capsules hanging from a capillary in a pendant drop geometry is developed, and shape equations are derived.

Their deformation behavior upon (a) changing gravity forces (by changing the phase contrast between liquids) and (b) reducing capsule volume is analyzed numerically. In case (a), the capsule stretches and sags and in case (b) we find a rich bifurcation behavior between buckled shapes; the preferred configurations are deduced from a least-energy principle. Based on theoretical results we develop a fitting procedure which allows us to extract the elastic moduli of the capsule membrane from experimental data.

We use similar methods to analyze the buckling behavior of spherical capsules upon reduction of the capsule volume. By preventing self-intersection for strongly reduced volume, we obtain a complete picture of the buckling process and can follow the transition from the undeformed configuration into the fully buckled state.