Berlin 2008 – wissenschaftliches Programm

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SYMS: Symposium Modern developments in multiphysics materials simulations

SYMS 3: Modern developments in multiphysics materials simulations III

SYMS 3.7: Vortrag

Freitag, 29. Februar 2008, 11:45–12:00, A 053

An ab-initio study of the hydrogen-bond network in crystalline α-chitin — •Michal Petrov, Martin Friák, Liverios Lymperakis, Dierk Raabe, and Jörg Neugebauer — Max-Planck-Institut für Eisenforschung GmbH, Max-Planck-Strasse 1, 402 37, Düsseldorf, Germany

Light, resistant and poly-functional α-chitin is the second most abundant biological polymer. Learning/understanding how nature achieves these properties is crucial to design novel bio-inspired materials. The hydrogen-bond network formed during the crystal packing plays a key role to understand the physical properties of the material such as solubility or elasticity. A deeper understanding of chitin’s unique properties has been long hindered by the lack of detailed ground-state structure information. We have therefore studied the atomic structure of crystalline α-chitin with a special focus on conformational possibilities in the hydrogen bond network. In order to properly address the full complexity of the α-chitin structure a hierarchical multischeme approach has been employed: The configurational space is first searched using force field based molecular dynamics and tight binding calculations. The most promising atomic configurations thus identified are then refined within accurate ab-initio methods. The properties of the hydrogen bond network within the rotational conformational phase space of the side chains and the influence to the energetics of α-chitin are investigated. Analyzing these results the stability of the ground-state structure as well as its strong elastic anisotropy is explained in terms of an intricate interplay between covalent and the hydrogen bonds.