Berlin 2015 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 15: P1: Interfaces and Thin Films

CPP 15.12: Poster

Montag, 16. März 2015, 16:00–19:00, Poster A

Shape and Wrinkle Analysis of deflated Elastic Capsules — •Jonas Hegemann, Sebastian Knoche, and Jan Kierfeld — TU Dortmund, 44221 Dortmund, Germany

Elastic capsules, prepared from droplets or bubbles attached to a capillary (as in a pendant drop tensiometer), can be deflated by suction through the capillary. We study this deflation and show that a combined analysis of the shape and wrinkling characteristics enables us to determine the elastic properties in situ. Shape contours are analyzed and fitted using shape equations derived from nonlinear membrane- shell theory to give the elastic modulus, Poisson ratio and stress distribution of the membrane. We include wrinkles, which generically form upon deflation, within the shape analysis. Measuring the wavelength of wrinkles and using the calculated stress distribution gives the bending stiffness of the membrane. We compare this method with previous approaches using the Laplace-Young equation and illustrate the method on polymerized octadecyltrichlorosilane (OTS) capsules. Our results are in agreement with the available rheological data.