Dresden 2006 – wissenschaftliches Programm

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AKB: Biologische Physik

AKB 40: Poster Session II

AKB 40.2: Poster

Mittwoch, 29. März 2006, 16:30–19:30, P3

Macroscopic crystallographic structure of Strongylocentrotus purpuratus and spisula solidissima by pole figure analysis — •Simone Herth¹, Jeremy K. Bigness², and Robert H. Doremus^1,2 — ¹Rensselaer Nanotechnology Center, Rensselaer Polytechnic Institute, Troy, NY, USA — ²Department of Materials Science and Engineering, Rensselaer Polytechnic Institute, Troy, NY, USA

The shells of sea animals, such as the sea urchin Strongylocentrotus purpuratus and the clam spisula solidissima, provide strong protection against enemies while retaining low weight. In Strongylocentrotus purpuratus the high toughness of the skeleton is achieved by the combination of a strong, but 50 % porous backbone made of the mineral calcite and proteins, which distribute stress concentrations. In contrast, the shell of spisula solidissima consists of the mineral aragonite and has a very low porosity. However, little is known about the macroscopic texture of these surprisingly strong composites, which was studied by a pole figure analysis of an oral and an aboral piece of the sea urchin skeleton and a small part of the clam shell. The sea urchin exhibits a strong texture in only a few crystallographic directions indicating a preferred macroscopic orientation of the calcite planes. The orientation of the planes in the aboral part is slightly more symmetric with about the same degree of texture. In contrast, the texture of the clam shell is very weak.