Voinescu, Alina E. and Touraud, Didier and Lecker, Alois and Pfitzner, Arno and Kienle, Lorenz and Kunz, Werner (2008) Initiation of Vaterite-Aragonite CaCO3 Particles from Silicate-Casein Sols. JOURNAL OF PHYSICAL CHEMISTRY C, 112 (45). pp. 17499-17506. ISSN 1932-7447,
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P-31 NMR difference spectra of sodium caseinate sols with and without silicate ions provide direct evidence of interactions between silicate ions and casein serine phosphate groups. The addition of Ca2+ to sodium caseinate solution without silicate ions and, subsequently, the diffusion of atmospheric CO2 to the resulting mixture do not lead to CaCO3 mineralization, whereas comparable experiments in the presence of silicate ions induce the precipitation of hemispherical three-component microstructures composed of silica, casein, and calcium carbonate. Apparently, the silicate-protein interaction plays a role as promoter for calcium carbonate mineralization in aqueous sols. X-ray diffraction (XRD) and Fourier-transform infrared (FTIR) analyses reveal that vaterite is the crystalline phase of the composites. The observed materials are flat on one side and curved outward on the other side. In time, the flat surface cracks to display a star-like shape. Occasionally, in the center of the crack, layer-by-layer sphere-like particles grow, probably due to a secondary nucleation. These spheres are composed of a large number of two-dimensional aragonitic sheets, which are densely packed and form a multilayered structure.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | NUCLEAR-MAGNETIC-RESONANCE; CALCIUM-CARBONATE; MICELLES; MILK; PRECIPITATION; PROTEINS; LYSOZYME; MODEL; ACID; BIOMINERALIZATION; |
| Subjects: | 500 Science > 540 Chemistry & allied sciences |
| Divisions: | Chemistry and Pharmacy > Institut für Anorganische Chemie > Chair Prof. Dr. Arno Pfitzner Chemistry and Pharmacy > Institut für Physikalische und Theoretische Chemie > Chair of Chemistry VI - Physical Chemistry (Solution Chemistry) > Prof. Dr. Werner Kunz |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 19 Oct 2020 07:09 |
| Last Modified: | 19 Oct 2020 07:09 |
| URI: | https://pred.uni-regensburg.de/id/eprint/30061 |
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