Regensburg 2007 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 35: SYBM Bioinspired Materials
MM 35.17: Poster
Donnerstag, 29. März 2007, 18:45–20:45, H16
Investigation of the Orientation Relationship Between α-Chitin and Calcite in Crustacean Cuticle Using Synchrotron x-ray Diffraction — •Ali Al-Sawalmih1, Helge Fabritius1, Sangbong Yi2, and Dierk Raabe1 — 1Max-Planck-Institut f. Eisenforschung, Max-Planck-Str. 1, 40237 Düsseldorf. — 2Institut für Werkstoffkunde und Werkstofftechnik, Technische Universität Clausthal, 38678 Clausthal-Zellerfeld.
Crustacean cuticle contains α-chitin-protein organic fibers associated with crystallites of calcite and considerable amounts of amorphous calcium carbonate (ACC). In this study, x-ray pole figure analysis was performed to investigate the crystallographic texture (preferred orientation) of the crystalline calcite and α-chitin, with respect to their orientation relationship, in edible crab Cancer pagurus and american lobster Homarus americanus cuticles using synchrotron wide-angle x-ray diffraction (XRD). It was observed that the c-axis of the calcite and the b-axis of the α-chitin are firstly preferentially aligned parallel to each other and secondly oriented along the surface normal. The other axes of the α-chitin and calcite are co-aligned with respect to each other throughout the cuticle plane. The synchrotron x-ray crystallographic texture results gave for the first time a statistical description of the orientation relationship between the organic and inorganic components in arthropod cuticle. This result strongly suggests that the fibrous structure of α-chitin assists the growth of calcite crystals in crustacean cuticle, by functioning directly or indirectly as a template for nucleation and subsequent growth of calcite.