Regensburg 2007 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 35: SYBM Bioinspired Materials

MM 35.23: Poster

Donnerstag, 29. März 2007, 18:45–20:45, H16

Hardness anisotropy of crystalline α-chitin: An ab-initio based conformational analysis — •Michal Petrov, Martin Friák, Liverios Lymperakis, Jörg Neugebauer, and Dierk Raabe — Max-Planck-Institut für Eisenforschung, Max-Planck-Strasse 1, 402 37, Düsseldorf, Germany

The α-chitin is one of the most abundant biological materials. The complex structure of α-chitin results in a low-weight and high-strength material, which make it a favorable system for potential bio-inspired functional materials applications. In order to gather a deeper understanding of the mechanical properties of α-chitin, study of the elastic properties of pure single-crystalline α-chitin is crucial. We have therefore explored the atomic structure and the hardness anisotropy of crystalline α-chitin. A challenge in identifying the equilibrium structure of α-chitin is the large size of the unit cell consisting of 108 atoms. In order to resolve this complex structure a series of hierarchical approaches/methods is used: A conformational analysis of chitin is performed using computationally fast empirical potentials and tight binding calculations. Based on the conformational analysis a small number of possible atomic configurations could be identified. These structures have then been used as input for accurate ab-initio calculations in order to derive the ground state atomic geometry and the elastic properties of chitin. Finally based on these results we discuss and explain the strong elastic anisotropy of α-chitin in terms of the interplay between covalent and hydrogen bonds.