Improved control of CaCO3 precipitation by direct carbon dioxide diffusion:: Application in mesocrystal assembly

We introduce a new crystallization method for CaCO3, via CO2 vapor diffusion into a Ca(OH)(2) solution. This method has the advantage of effectively introducing only the ions needed for crystallization so that the solution ionic strength can be controlled and the influence of spectator ions on crystallization can be studied. As a further advantage, a pH close to biological conditions is approached at the end of the crystallization reaction, and the kinetics of the reaction can be influenced via the initial pressure in the closed crystallization setup. The method was validated for two examples of CaCO3 crystallization via polymer-mediated mesoscale assembly.