TEMPLATED GROWTH OF CALCITE, VATERITE AND ARAGONITE CRYSTALS ON SELF-ASSEMBLED MONOLAYERS OF SUBSTITUTED ALKYLTHIOLS ON GOLD

Making use of extensive scanning electron microscopy and the Rietveld analysis of X-ray diffraction profiles, we have studied the morphology , crystal habits and phase compositions of crystals of calcium carbona te grown on modified organic surfaces by precipitation from solution. The studies have been aimed at modeling natural biomineralization proc esses of the ubiquitous mineral forms of CaCO3, viz. calcite, vaterite and aragonite. The parameters that could be controlled and were indee d found to drastically influence the crystallization were the thiol ch ain length, the omega-substituent on the thiol and the temperature at which crystallization was carried out. As many as ten different thiol modified substrates, apart from glass and clean gold surfaces were use d for the templating. Such a heuristic study offers considerable insig ht into the nature of templated crystallization and has implications f or the understanding of biomineralization processes.