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AKB: Biologische Physik

AKB 50: Poster Session "Biological Physics"

AKB 50.89: Poster

Freitag, 12. März 2004, 10:30–13:00, B

Complex Crystal Growth of CaCO₃ controlled by Diblock-Copolymer Solutions — •Antje Reinecke¹, Helmut Cölfen¹, and Hans-Günther Döbereiner^1,2 — ¹Max-Planck-Institut für Kolloid- und Grenzflächenforschung, D-14424 Potsdam — ²Department of Biology, Columbia University, New York, NY 10027

The morphology of CaCO₃ crystals grown from Na₂CO₃ and CaCl₂ solutions in a double jet reactor is extensively modified in the presence of Poly(ethyleneoxide)-block-Poly(methacrylic acid). We observe growth via rod, dumbell and final sphere morphologies using electron and phase-contrast microscopy. It is well known that diblock-copolymer additives influence strongly crystal shapes. However, so far, detailed morphological sequences during crystal growth have not been reported. For the first time, we present a quantitative characterization of crystal shapes and their growth dynamics. Extensive phase-contrast microscopy studies are statistically analyzed to provide the dynamics of shape distributions over time. Electron microscopy gives high resolution images of faceted crystal shapes. We correlate crystal morphology to dynamic free ion concentration measurements using Ca⁺⁺ sensitive electrodes.