Regensburg 2010 – scientific programme
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BP: Fachverband Biologische Physik
BP 37: Biomaterials
BP 37.3: Talk
Friday, March 26, 2010, 10:45–11:00, H43
The nanostructure of biogenic calcite: a 3D SAXS/WAXS study. — •Christoph Gilow1, Barbara Aichmayer1, Chenghao Li1, Stefan Siegel1, Oskar Paris2, Emil Zolotoyabko3, and Peter Fratzl1 — 1Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, Research Campus Golm, 14424 Potsdam, Germany — 2Institute of Physics, University of Leoben, A-8700 Leoben, Austria — 3Department of Materials Engineering, Technion - Israel Institute of Technology, Haifa 32000, Israel
Biogenic crystals grow in the presence of organic macromolecules which influence their shape and internal structure, often resulting in superior material characteristics. Calcitic prisms from the shell of the Pinna nobilis scatter like single crystals, despite containing significant amounts of intra-crystalline organic macromolecules which cause anisotropic distortions of the calcite unit cells. Individual prisms were investigated by means of 3D wide- and small-angle scattering (SAXS/WAXS) using synchrotron radiation at the µ-Spot beamline, BESSY II, Helmholtz Zentrum Berlin. The SAXS signal was also found to be strongly anisotropic and had a fixed orientation correlation to the WAXS pattern. Additional insights into the nanostructure of calcitic prisms and the organic-mineral interfaces were gained by laboratory SAXS measurements on powdered samples as well as by SEM studies on etched samples. Annealing the prisms at 300∘C, a temperature which was chosen to mainly affect the organic macromolecules, led to substantial structure rearrangements on a nano-scale.