Kellermeier, Matthias and Melero-Garcia, Emilio and Glaab, Fabian and Eiblmeier, Josef and Kienle, Lorenz and Rachel, Reinhard and Kunz, Werner and Manuel Garcia-Ruiz, Juan (2012) Growth Behavior and Kinetics of Self-Assembled Silica-Carbonate Biomorphs. CHEMISTRY-A EUROPEAN JOURNAL, 18 (8). pp. 2272-2282. ISSN 0947-6539, 1521-3765
Full text not available from this repository. (Request a copy)Abstract
Upon slow crystallization from silica-containing solutions or gels at elevated pH, alkaline-earth carbonates spontaneously self-assemble into remarkable nanocrystalline ultrastructures. These so-called silica biomorphs exhibit curved morphologies beyond crystallographic symmetry and ordered textures reminiscent of the hierarchical design found in many biominerals. The formation of these fascinating materials is thought to be driven by a dynamic coupling of the components speciations in solution, which causes concerted autocatalytic mineralization of silica-stabilized nanocrystals over hours. In the present work, we have studied the precipitation kinetics of this unique system by determining growth rates of individual aggregates using video microscopy, and correlated the results with time-dependent data on the concentration of metal ions and pH acquired online during crystallization. In this manner, insight to the evolution of chemical conditions during growth was gained. It is shown that crystallization proceeds linearly with time and is essentially reaction controlled, which fits well in the proposed morphogenetic scenario, and thus, indirectly supports it. Measurements of the silica concentration in solution, combined with analyses of crystal aggregates isolated at distinct stages of morphogenesis, further demonstrate that the fraction of silica coprecipitated with carbonate during active growth is rather small. We discuss our findings with respect to the role of silica in the formation of biomorphs, and moreover, prove that the external silica skins that occasionally sheath the aggregates-previously supposed to be involved in the growth mechanism originate from secondary precipitation after growth is already terminated.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | BARIUM CARBONATE; RICH ENVIRONMENTS; CRYSTALS; PRECIPITATION; MORPHOLOGY; ARAGONITE; NACRE; CRYSTALLIZATION; MINERALIZATION; NANOCRYSTALS; barium; biomimetic synthesis; biomorphs; kinetics; self-assembly; silica |
| Subjects: | 500 Science > 540 Chemistry & allied sciences 500 Science > 570 Life sciences |
| Divisions: | Biology, Preclinical Medicine > Institut für Biochemie, Genetik und Mikrobiologie > Lehrstuhl für Mikrobiologie (Archaeenzentrum) > Prof. Dr. Reinhard Rachel 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 May 2020 11:12 |
| Last Modified: | 19 May 2020 11:12 |
| URI: | https://pred.uni-regensburg.de/id/eprint/19279 |
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