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A Systematic Examination of the Morphogenesis of Calcium Carbonate in the Presence of a Double‐Hydrophilic Block Copolymer
Author(s) -
Cölfen Helmut,
Qi Limin
Publication year - 2001
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/1521-3765(20010105)7:1<106::aid-chem106>3.0.co;2-d
Subject(s) - materials science , crystallization , calcite , copolymer , polymer , morphology (biology) , chemical engineering , calcium carbonate , crystallite , crystal (programming language) , amorphous solid , ethylene glycol , polymer chemistry , crystallography , mineralogy , composite material , chemistry , biology , computer science , engineering , metallurgy , genetics , programming language
In this paper, a systematic study of the influence of various experimental parameters on the morphology and size of CaCO 3 crystals after room‐temperature crystallization from water in the presence of poly(ethylene glycol)‐ block ‐poly(methacrylic acid) (PEG‐ b ‐PMAA) is presented. The pH of the solution, the block copolymer concentration, and the ratio [polymer]/[CaCO 3 ] turned out to be important parameters for the morphogenesis of CaCO 3 , whereas a moderate increase of the ionic strength (0.016 M ) had no influence. Depending on the experimental conditions, the crystal morphologies can be tuned from calcite rhombohedra via rods, ellipsoids or dumbbells to spheres. A morphology map is presented which allows the prediction of the crystal morphology from a combination of pH, and CaCO 3 and polymer concentration. Morphologies reported in literature for the same system but under different crystallization conditions agree well with the predictions from the morphology map. A closer examination of the growth of polycrystalline macroscopic CaCO 3 spheres by TEM and time‐resolved dynamic light scattering showed that CaCO 3 macrocrystals are formed from strings of aggregated amorphous nanoparticles and then recrystallize as dumbbell‐shaped or spherical calcite macrocrystal.