Inorganic Self-Organized Silica Aragonite Biomorphic Composites,
Alina E. Voinescu, Matthias Kellermeier, Anna M. Carnerup, Ann-Kristin Larsson, Didier Touraud, Werner Kunz, Lorenz Kienle,
Arno Pfitzner, and Stephen T. Hyde,
Crystal Growth and Design 8(5)
(2008) 515-521.
Abstract
The pptn. of calcium carbonate in alk. silica solns. results in the formation of complex curvilinear forms if
aragonite formation is encouraged by growth at an elevated temp. (80 DegC). The resulting coralline
self-assembled silica-calcium carbonate particles are "biomorphs", bearing a striking resemblance to natural coral forms.
These materials, comprised of calcium carbonate nanocrystals and an amorphous silica matrix, have a complex ultrastructure,
made of clusters of gathered sheets of variable curvatures formed by successive curling. The nanocrystals within these
"ruled surfaces" are thin, elongated, densely packed needles of aragonite. These clusters are outgrowths from central
saddlelike cores that resemble developable petaloid surfaces. The size, shape, crystallog., and chem. compn. of the
resulting biomorphs were examd. by optical microscopy, field emission SEM (FE-SEM), powder X-ray diffractometry (XRD),
Fourier transform IR spectroscopy (FT-IR), transmission electron microscopy (TEM and HRTEM), and energy dispersive X-ray anal. (EDX).
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