caa a22 4500 475764900 CHVBK 20180406123602.0 cr unu---uuuuu 170329e20000201xx s 000 0 eng 10.1007/s003960050028 doi (NATIONALLICENCE)springer-10.1007/s003960050028 Shear-induced deformations of polyamide microcapsules [Elektronische Daten] [A. Walter, H. Rehage, H. Leonhard] The application of microcapsules for technical, cosmetic and pharmaceutical purposes has attracted increased interest in recent years. The design of new capsule types requires a profound knowledge of their mechanical properties. Rheological studies provide interesting information on intrinsic membrane properties and this information can be used to avoid premature release of encapsulated compounds due to the action of external mechanical forces (stirring, swallowing, spreading). In this publication we report a systematic study of polyamide microcapsules. These particles were synthesized by reacting 4-aminomethyl-1,8-diaminooctane and sebacoyl dichloride at the interface between silicone oil and water. Two different experiments were performed to get information on the mechanical properties of the capsule walls. First of all, we used an optical rheometer (rheoscope) to observe the capsule deformation and orientation in shear flow. The polymerization kinetics, relaxation properties, the regime of linear-viscoelastic behavior and the shear modulus of the flat membranes were independently measured in an interfacial rheometer. Both experiments gave complementary results. It turned out that the two-dimensional elongational modulus was about 3-4 times larger than the shear modulus. This result is in fairly good agreement with a theoretical model recently proposed by Barthès-Biesel. Due to the simple synthesis and well-defined structure, polyamide microcapsules can also serve as simple model systems to understand the complicated flow properties of red blood cells. Springer-Verlag Berlin Heidelberg, 2000 Key words Microcapsule nationallicence Interfacial polymerization nationallicence Deformation nationallicence Young's modulus nationallicence Shear modulus nationallicence Walter A. Institut für Umweltanalytik Universität Essen, Universitätsstrasse 3-5 D-45141 Essen, Germany e-mail: anja.walter@uni-essen.de Tel.: +49-201-1833988 Fax: +49-201-1833951, DE aut Rehage H. Institut für Umweltanalytik Universität Essen, Universitätsstrasse 3-5 D-45141 Essen, Germany e-mail: anja.walter@uni-essen.de Tel.: +49-201-1833988 Fax: +49-201-1833951, DE aut Leonhard H. Institut für Umweltanalytik Universität Essen, Universitätsstrasse 3-5 D-45141 Essen, Germany e-mail: anja.walter@uni-essen.de Tel.: +49-201-1833988 Fax: +49-201-1833951, DE aut https://doi.org/10.1007/s003960050028 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s003960050028 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Walter A. Institut für Umweltanalytik Universität Essen, Universitätsstrasse 3-5 D-45141 Essen, Germany e-mail: anja.walter@uni-essen.de Tel.: +49-201-1833988 Fax: +49-201-1833951, DE aut NATIONALLICENCE 700 1- Rehage H. Institut für Umweltanalytik Universität Essen, Universitätsstrasse 3-5 D-45141 Essen, Germany e-mail: anja.walter@uni-essen.de Tel.: +49-201-1833988 Fax: +49-201-1833951, DE aut NATIONALLICENCE 700 1- Leonhard H. Institut für Umweltanalytik Universität Essen, Universitätsstrasse 3-5 D-45141 Essen, Germany e-mail: anja.walter@uni-essen.de Tel.: +49-201-1833988 Fax: +49-201-1833951, DE aut Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer