Details
| Original language | English |
|---|---|
| Pages (from-to) | 4301-4311 |
| Number of pages | 11 |
| Journal | Advanced functional materials |
| Volume | 22 |
| Issue number | 20 |
| Publication status | Published - 23 Oct 2012 |
| Externally published | Yes |
Abstract
Calcium carbonate precipitation proceeds via a complex multistage scenario involving neutral ion clusters as precursors and amorphous phases as intermediates, which finally transform to crystals. Although the existence of stable clusters in solution prior to nucleation has been demonstrated, the molecular mechanisms by which they precipitate are still obscure. Here, direct insight into the processes that drive the transformation of individual clusters into amorphous nanoparticles is provided by progressive colloidal stabilization of different transient states in silica-containing environments. Nucleation of calcium carbonate in the presence of silica can only take place via cluster aggregation at low pH values. At higher pH, prenucleation clusters become colloidally stabilized and cannot aggregate. Nucleation through structural reorganization within the clusters is not observed under these conditions, indicating that this pathway is blocked by kinetic and/or thermodynamic means. The degree of stabilization against nucleation is found to be sufficient to allow for a dramatic enrichment of solutions with prenucleation clusters and enable their isolation into the dry state. This approach renders direct analyses of the clusters by conventional techniques possible and is thus likely to facilitate deeper insight into the chemistry and structure of these elusive species in the future. Under suitable conditions, added silica binds to ion clusters that exist in CaCO 3 solutions prior to nucleation. The resulting colloidal interactions can be tuned to either fully prevent nucleation and isolate the clusters or allow for their gradual transformation into amorphous nanoparticles. The processes underlying homogeneous nucleation of CaCO 3 become decelerated and can be observed experimentally.
Keywords
- calcium carbonate, crystal growth, nucleation, phase transitions, silica
ASJC Scopus subject areas
- Chemistry(all)
- General Chemistry
- Materials Science(all)
- General Materials Science
- Physics and Astronomy(all)
- Condensed Matter Physics
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In: Advanced functional materials, Vol. 22, No. 20, 23.10.2012, p. 4301-4311.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Colloidal stabilization of calcium carbonate prenucleation clusters with silica
AU - Kellermeier, Matthias
AU - Gebauer, Denis
AU - Melero-García, Emilio
AU - Drechsler, Markus
AU - Talmon, Yeshayahu
AU - Kienle, Lorenz
AU - Cölfen, Helmut
AU - García-Ruiz, Juan Manuel
AU - Kunz, Werner
PY - 2012/10/23
Y1 - 2012/10/23
N2 - Calcium carbonate precipitation proceeds via a complex multistage scenario involving neutral ion clusters as precursors and amorphous phases as intermediates, which finally transform to crystals. Although the existence of stable clusters in solution prior to nucleation has been demonstrated, the molecular mechanisms by which they precipitate are still obscure. Here, direct insight into the processes that drive the transformation of individual clusters into amorphous nanoparticles is provided by progressive colloidal stabilization of different transient states in silica-containing environments. Nucleation of calcium carbonate in the presence of silica can only take place via cluster aggregation at low pH values. At higher pH, prenucleation clusters become colloidally stabilized and cannot aggregate. Nucleation through structural reorganization within the clusters is not observed under these conditions, indicating that this pathway is blocked by kinetic and/or thermodynamic means. The degree of stabilization against nucleation is found to be sufficient to allow for a dramatic enrichment of solutions with prenucleation clusters and enable their isolation into the dry state. This approach renders direct analyses of the clusters by conventional techniques possible and is thus likely to facilitate deeper insight into the chemistry and structure of these elusive species in the future. Under suitable conditions, added silica binds to ion clusters that exist in CaCO 3 solutions prior to nucleation. The resulting colloidal interactions can be tuned to either fully prevent nucleation and isolate the clusters or allow for their gradual transformation into amorphous nanoparticles. The processes underlying homogeneous nucleation of CaCO 3 become decelerated and can be observed experimentally.
AB - Calcium carbonate precipitation proceeds via a complex multistage scenario involving neutral ion clusters as precursors and amorphous phases as intermediates, which finally transform to crystals. Although the existence of stable clusters in solution prior to nucleation has been demonstrated, the molecular mechanisms by which they precipitate are still obscure. Here, direct insight into the processes that drive the transformation of individual clusters into amorphous nanoparticles is provided by progressive colloidal stabilization of different transient states in silica-containing environments. Nucleation of calcium carbonate in the presence of silica can only take place via cluster aggregation at low pH values. At higher pH, prenucleation clusters become colloidally stabilized and cannot aggregate. Nucleation through structural reorganization within the clusters is not observed under these conditions, indicating that this pathway is blocked by kinetic and/or thermodynamic means. The degree of stabilization against nucleation is found to be sufficient to allow for a dramatic enrichment of solutions with prenucleation clusters and enable their isolation into the dry state. This approach renders direct analyses of the clusters by conventional techniques possible and is thus likely to facilitate deeper insight into the chemistry and structure of these elusive species in the future. Under suitable conditions, added silica binds to ion clusters that exist in CaCO 3 solutions prior to nucleation. The resulting colloidal interactions can be tuned to either fully prevent nucleation and isolate the clusters or allow for their gradual transformation into amorphous nanoparticles. The processes underlying homogeneous nucleation of CaCO 3 become decelerated and can be observed experimentally.
KW - calcium carbonate
KW - crystal growth
KW - nucleation
KW - phase transitions
KW - silica
UR - http://www.scopus.com/inward/record.url?scp=84867547562&partnerID=8YFLogxK
U2 - 10.1002/adfm.201200953
DO - 10.1002/adfm.201200953
M3 - Article
AN - SCOPUS:84867547562
VL - 22
SP - 4301
EP - 4311
JO - Advanced functional materials
JF - Advanced functional materials
SN - 1616-301X
IS - 20
ER -