Crystalline Order of a Water/Glycine Film Coadsorbed on the (104) Calcite Surface

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• 作者：Uta Magdans ; Xavier Torrelles ; Klaus Angermund ; Hermann Gies ; Jordi Rius
• 刊名：Langmuir
• 出版年：2007
• 出版时间：April 24, 2007
• 年：2007
• 卷：23
• 期：9
• 页码：4999 - 5004
• 全文大小：247K
• 年卷期：v.23,no.9(April 24, 2007)
• ISSN：1520-5827

文摘

For biomineralization processes, the interaction of the surface of calcite crystals with organic molecules is ofparticular importance. Especially, biologically controlled biomineralization as in exoskeletons of mollusks andechinoderms, e.g., sea urchin with single-crystal-like spines and shells,^1-3 requires molecular control of seed formationand growth process. So far, experiments showing the obvious influence of organic molecules on the morphology andhabit of calcite crystals have demonstrated the molecular dimension of the interaction.^4-7 Details of the kinetics ofgrowth and dissolution of mineral surfaces influenced by additives are available,^8,9 but other experimental data aboutthe structure of the organic/inorganic interface on the atomic scale are rare. On the other hand, complicated organicmacromolecules which are involved in biomineralization are numerous, with only a small fraction solved in structureand function so far.^10-13 Therefore, model systems have to be designed to provide a basic understanding for theinteraction process.¹⁴ Using grazing incidence X-ray diffraction combined with molecular modeling techniques, weshow that glycine molecules order periodically on the calcite (104) face in competition with the solvent water whenexposed to an aqueous solution of the most simple amino acid. In contrast to the general concept of the charge-matchingfit of organic molecules on mineral surfaces,^4,14 glycine is not attached to the calcite surface directly but substitutesfor water molecules in the second hydration layer.