Models for the nucleation and growth of calcium carbonate

COMP 243

John H Harding,, Colin L Freeman,, Mingjun Yang, mjyang@nano.ku.dk2, David J. Cooke,, James A. Elliott,, Dorothy M Duffy,, Jennifer Lardge5, David Quigley6, and P. M. Rodger, (1) Department of Engineering Materials, University of Sheffield, Mappin St, Sheffield, S1 3JD, United Kingdom, (2) Nano-Science Center, University of Copenhagen, Copenhagen, Denmark, (3) School of Applied Sciences, University of Huddersfield, Huddersfield, United Kingdom, (4) Department of Materials Science and Metallurgy, University of Cambridge, Pembroke Street, Cambridge, CB2 3QZ, United Kingdom, (5) London Centre for Nanotechnology, University College London, London, United Kingdom, (6) Department of Chemistry and Centre for Scientific Computing, University of Warwick, Gibbet Hill Rd, Coventry, CV4 7AL, United Kingdom
The nucleation and growth of calcium carbonate is important in fields from biomineralization through geology to industrial processes. We show how the growth and morphology of calcite can be controlled by organic molecules such as polysaccharides, peptides and proteins or by molecular arrays by calculating absorption energies (for molecules) and interfacial energies (for the arrays). We have considered the nucleation of calcite using mechanisms other that those based on classical nucleation theory. Simulation of nano-particles allows size and shape-dependent properties to be studied directly. The presence and structure of surface water and the effects of organic molecules and arrays are all important in determining their structure. Simulations using metadynamics have shown both that amorphous calcium carbonate is the stable form for small particles and that it is stabilised by proteins. We shall also present results on the interactions of nanoparticles and proteins and their relevance to the structure of egg-shells.

Poster Session
6:00 PM-8:00 PM, Tuesday, August 18, 2009 Walter E. Washington Convention Center -- Ballroom A, Poster

Division of Computers in Chemistry

The 238th ACS National Meeting, Washington, DC, August 16-20, 2009