Back Cover: Hydrogels from Amorphous Calcium Carbonate and Polyacrylic Acid: Bio-Inspired Materials for “Mineral Plastics” (Angew. Chem. Int. Ed. 39/2016)

2016 ◽  
Vol 55 (39) ◽  
pp. 12110-12110
Author(s):  
Shengtong Sun ◽  
Li-Bo Mao ◽  
Zhouyue Lei ◽  
Shu-Hong Yu ◽  
Helmut Cölfen
2004 ◽  
Vol 847 ◽  
Author(s):  
Swaminathan Sindhu ◽  
Parayil K. Ajikumar ◽  
Subbiah Jegadesan ◽  
Suresh Valiyaveettil

ABSTRACTThe present paper describes the mineralization of calcium carbonate at a low temperature (4 °C) and in presence of additives. Aspartic acid immobilized polyacrylic acid (PA-Asp) induced the nucleation of spherical vaterite polymorph at 4 °C. But at room temperature, a thin film of calcite was deposited. Moreover, stable amorphous calcium carbonate was precipitated in presence of magnesium at low temperature. The observed results show that low temperature and presence of additives influence the nucleation, polymorph selectivity and morphology of the precipitated calcium carbonate.


2016 ◽  
Vol 55 (39) ◽  
pp. 11765-11769 ◽  
Author(s):  
Shengtong Sun ◽  
Li-Bo Mao ◽  
Zhouyue Lei ◽  
Shu-Hong Yu ◽  
Helmut Cölfen

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Michika Sawada ◽  
Kandi Sridhar ◽  
Yasuharu Kanda ◽  
Shinya Yamanaka

AbstractWe report a synthesis strategy for pure hydroxyapatite (HAp) using an amorphous calcium carbonate (ACC) colloid as the starting source. Room-temperature phosphorylation and subsequent calcination produce pure HAp via intermediate amorphous calcium phosphate (ACP). The pre-calcined sample undergoes a competitive transformation from ACC to ACP and crystalline calcium carbonate. The water content, ACC concentration, Ca/P molar ratio, and pH during the phosphorylation reaction play crucial roles in the final phase of the crystalline phosphate compound. Pure HAp is formed after ACP is transformed from ACC at a low concentration (1 wt%) of ACC colloid (1.71 < Ca/P < 1.88), whereas Ca/P = 1.51 leads to pure β-tricalcium phosphate. The ACP phases are precursors for calcium phosphate compounds and may determine the final crystalline phase.


2020 ◽  
Vol 22 (4) ◽  
pp. 1900922 ◽  
Author(s):  
Christoph Lauer ◽  
Sebastian Haußmann ◽  
Patrick Schmidt ◽  
Carolin Fischer ◽  
Doreen Rapp ◽  
...  

2008 ◽  
Vol 105 (45) ◽  
pp. 17362-17366 ◽  
Author(s):  
Y. Politi ◽  
R. A. Metzler ◽  
M. Abrecht ◽  
B. Gilbert ◽  
F. H. Wilt ◽  
...  

1997 ◽  
Vol 264 (1380) ◽  
pp. 461-465 ◽  
Author(s):  
Elia Beniash ◽  
Joanna Aizenberg ◽  
Lia Addadi ◽  
Stephen Weiner

2008 ◽  
Vol 72 (1) ◽  
pp. 227-231 ◽  
Author(s):  
M. J. I. Briones ◽  
E. López ◽  
J. Méndez ◽  
J. B. Rodríguez ◽  
L. Gago-Duport

AbstractThe earthworm calciferous gland produces a concentrated suspension of calcium carbonate and in certain species precipitates as concretions of CaCO3, which then enter the soil. Here we investigated the initial stages of CaCO3 formation in the earthworm Lumbricus friendi by means of Fourier transform infrared and electron microscopy techniques (field-emission scanning electron microscopy, transmission electron microscopy, high resolution electron microscopy and selected area electron diffraction). In addition, comparisons between the IR spectra of the water-dissolved carbonic anhydrase (CA) and the glandular secretion (‘milky fluid’) were performed in order to investigate the mechanisms involved in CaCO3 precipitation. Our results strongly suggest that carbonation starts with the dissolved CO2, which is transformed via deprotonation to HCO3-, then to CO32- and finally to amorphous calcium carbonate (ACC). While ACC stabilization takes place under the biological control, further transformation stages leading to calcite concretions seem to be inorganically driven by an Ostwald ripening process.


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