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Rosette‐Shaped Calcite Structures at Surfaces: Mechanistic Implications for CaCO 3 Crystallization
Author(s) -
Yang Sung Ho,
Choi Insung S.
Publication year - 2010
Publication title -
chemistry – an asian journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.18
H-Index - 106
eISSN - 1861-471X
pISSN - 1861-4728
DOI - 10.1002/asia.201000190
Subject(s) - calcite , crystallization , biomineralization , rosette (schizont appearance) , methacrylate , chemical engineering , materials science , amorphous solid , macromolecule , matrix (chemical analysis) , acrylic acid , crystallography , polymer chemistry , chemistry , mineralogy , polymer , composite material , monomer , biochemistry , engineering , immunology , biology
Biomineralization is believed to be achieved by the intimate cooperation of soluble macromolecules and an insoluble matrix at the specific inorganic–organic interface. It has been reported that positively charged matrices play an important role in controlling the structure of CaCO 3 at surfaces, although detailed mechanisms remain unclear. In this work, we studied the transformation from amorphous CaCO 3 to calcite crystals on surfaces by using thin films of poly(2‐(dimethylamino)ethyl methacrylate) (PDMAEMA) and its quaternized form. The positively charged PDMAEMA film was found to possess unique properties for CaCO 3 crystallization: individually separated, single calcite crystals were formed on the PDMAEMA film in the absence of poly(acrylic acid) (PAA), while circularly fused calcite crystals were formed in the presence of PAA. The circularly fused (rosette‐shaped) calcite crystals could be changed from a completely packed rosette to a ring‐shaped, hollow structure by tuning the crystallization conditions. A number of factors, such as reaction time, amount of (NH 4 ) 2 CO 3 , concentration of PAA, and charge of matrix‐films, were varied systematically, and we now propose a mechanism based on these observations.