title: Deformation of liquid-filled calcium alginate capsules in a spinning drop apparatus.
abstract: This paper describes the mechanical properties of thin-walled, liquid-filled calcium alginate capsules by measuring the deformation of these particles in a spinning drop apparatus. By variation of the guluronic acid content of the alginate, the polymerization time and the calcium and alginate concentration we systematically studied the elastic properties of these capsules. In a series of experiments we observed for the first time new types of irreversibly deformed capsules, which can be described by plastic deformation. For comparison purposes, we also investigated liquid-filled calcium alginate particles in squeezing capsule experiments. The qualitative and quantitative results of both experiments in terms of the deformation properties and the surface Young moduli were in good agreement. Furthermore we also investigated liquid-filled calcium alginate particles by NMR microscopy to characterize the capsules in view of their membrane thickness. These results, in combination with the spinning capsule experiments allowed us to measure the kinetics of surface gelation and the mechanism of membrane growing.
authors.affiliation: Department of Physical Chemistry II, Technische Universität Dortmund, 44227 Dortmund, Otto-Hahn-Strasse 6, Germany. sabine.leick@tu-dortmund.de
authors.forename: Sabine
authors.initials: S
authors.lastname: Leick
authors.forename: Stefan
authors.initials: S
authors.lastname: Henning
authors.forename: Patrick
authors.initials: P
authors.lastname: Degen
authors.forename: Dieter
authors.initials: D
authors.lastname: Suter
authors.forename: Heinz
authors.initials: H
authors.lastname: Rehage
mesh_terms: D000464:Alginates / Q000737:chemistry*; D002118:Calcium / Q000737:chemistry*; D002214:Capsules / Q000737:chemistry; D005782:Gels / Q000737:chemistry; D020723:Glucuronic Acid / Q000737:chemistry; D006603:Hexuronic Acids / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D013314:Stress, Mechanical
chemical_list: D000464:Alginates; D002214:Capsules; D005782:Gels; D006603:Hexuronic Acids; D020723:Glucuronic Acid; D002118:Calcium