Superstructures of Calcium Carbonate Crystals by Oriented Attachment

Gehrke, Nicole; Cölfen, Helmut; Pinna, Nicola; Antonietti, Markus; Nassif, Nadine

doi:10.1021/cg050051d

Cited by 240 publications

(274 citation statements)

References 31 publications

Supporting

Mentioning

251

Contrasting

Unclassified

Order By: Relevance

“…Additives including certain polymers, [28][29][30] small molecules, 31 and the ammonium ion [32][33][34] can uniquely promote the formation of vaterite, and vaterite has been precipitated in microemulsions of CTAB (cetyl trimethylammonium bromide) and water-in-oil microemulsions of sodium dodecyl sulphate (SDS). 35 A microwave-assisted method was applied to produce vaterite with a range of morphologies from water/ethylene glycol mixtures in the presence of the additives CTAB and SDS, 36 while stacks of vaterite platelets were produced on precipitation from a viscous solution of hydroxyethyl cellulose (HEC).…”

Section: Discussionmentioning

confidence: 99%

Calcium carbonate polymorph control using droplet-based microfluidics

2012

View full text Add to dashboard Cite

Calcium carbonate (CaCO 3 ) is one of the most abundant minerals and of high importance in many areas of science including global CO 2 exchange, industrial water treatment energy storage, and the formation of shells and skeletons. Industrially, calcium carbonate is also used in the production of cement, glasses, paints, plastics, rubbers, ceramics, and steel, as well as being a key material in oil refining and iron ore purification. CaCO 3 displays a complex polymorphic behaviour which, despite numerous experiments, remains poorly characterised. In this paper, we report the use of a segmented-flow microfluidic reactor for the controlled precipitation of calcium carbonate and compare the resulting crystal properties with those obtained using both continuous flow microfluidic reactors and conventional bulk methods. Through combination of equal volumes of equimolar aqueous solutions of calcium chloride and sodium carbonate on the picoliter scale, it was possible to achieve excellent definition of both crystal size and size distribution. Furthermore, highly reproducible control over crystal polymorph could be realised, such that pure calcite, pure vaterite, or a mixture of calcite and vaterite could be precipitated depending on the reaction conditions and dropletvolumes employed. In contrast, the crystals precipitated in the continuous flow and bulk systems comprised of a mixture of calcite and vaterite and exhibited a broad distribution of sizes for all reaction conditions investigated.

show abstract

Section: Discussionmentioning

confidence: 99%

Calcium carbonate polymorph control using droplet-based microfluidics

2012

View full text Add to dashboard Cite

show abstract

“…Thus, the conditions under which crystallization occurred in these experiments are (at least roughly) comparable to those prevailing in the titration assays (pH 9.75). Eventually, after two weeks of exposure, the coverslips (now covered with crystals) were removed from the vials and rinsed with distilled water and acetone, followed by drying at 40 C. Two weeks of ripening time were chosen to ensure equilibrium conditions as the gasdiffusion method was shown to be highly dependent on kinetic factors [42,43]. Each amino acid was investigated twice in this manner, using different desiccators (though with identical inner volumes) in order to test reproducibility.…”

Section: Caco 3 Crystallization By Vapor Diffusionmentioning

confidence: 99%

The multiple effects of amino acids on the early stages of calcium carbonate crystallization

Picker¹,

Kellermeier²,

Seto³

et al. 2012

Zeitschrift Für Kristallographie - Crystalline Materials

Self Cite

109

View full text Add to dashboard Cite

Abstract. Proteins have found their way into many of Nature's structures due to their structural stability, diversity in function and composition, and ability to be regulated as well as be regulators themselves. In this study, we investigate the constitutive amino acids that make up some of these proteins which are involved in CaCO 3 mineralization -either in nucleation, crystal growth, or inhibition processes. By assaying all 20 amino acids with vapor diffusion and in situ potentiometric titration, we have found specific amino acids having multiple effects on the early stages of CaCO 3 crystallization. These same amino acids have been independently implicated as constituents in liquid-like precursors that form mineralized tissues, processes believed to be key effects of biomineralization proteins in several biological model systems.

show abstract

“…Such a mechanism has been invoked to explain the nanodomain structure of some inorganically precipitated vaterite samples (e.g. Gehrke et al, 2005;Zhuo et al, 2010). Although our present data is insufficient to definitively rule out this possibility, it is thought that the relatively large-scale crystallographic alignment present within the vaterite, the occasional presence of higher levels of organisation (e.g.…”

Section: Vaterite Nanostructure and Crystallography On The Nanometre mentioning

confidence: 99%