Dresden 2003 – wissenschaftliches Programm
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CPP: Chemische Physik und Polymerphysik
CPP 2: Colloide, Nanopartikel und Kapseln
CPP 2.6: Vortrag
Montag, 24. März 2003, 11:30–11:45, ZEU/260
Nucleation and Growth of CaCO3 Minerals in Presence of Polymer Additives Studied by Small-Angle Synchrotron X-ray Scattering — •Andriy Fomenko1, Hitoshi Endo2, Sven Hoffmann3, and Dieter Richter1 — 1Institute for Solid State Research, Research Center Jülich, Germany — 2Max-Planck-Institute of Colloids and Interfaces, Gölm — 3Dubble CRG, European Synchrotron Radiation Facility, B. P. 220, F-38043 Grenoble Cedex, France
The process of nucleation and growth of calcium carbonate (CaCO3) in presence of double-hydrophilic block copolymer poly(ethylenglycol)-block-poly(methacrylic acid) was studied by small-angle X-ray scattering (SAXS). The SAXS technique offers the opportunity to follow the process of mineralisation in details by time resolved experiments, where the high intensity of synchrotron radiation allows a much higher time resolution and a largely reduced scattering volume. These properties allow the exploration of the early stages of the CaCO3 precipitation.
The mineralisation process was started by exposing a CaCl2 solution to a CO2 gas atmosphere. The precipitation reaction was followed by SAXS over a time period of about four hours with a time resolution of one minute. The CaCl2 concentration in solution was varied over two orders of magnitude at a given weight fraction of the polymer (3 wt.%). The direct comparison of precipitation reactions with and without the double-hydrophilic polymer confirms that the time-scale of the CaCO3 mineralisation is strongly affected by the polymer as well as the morphology of CaCO3 [1].
[1] H. Cölfen and L. Qi, Chem. Eur. J. 7, 106 (2001)