DIPARTIMENTO DI FISICA

"Stability and growth of CaCO3 nano-particles"

 dr. P. Raiteri (Curtin University, Perth, WA)

Giovedi’ 27 gennaio, ore 15.00

Aula C del Dip.to di Fisica (Cittadella Universitaria)
 

Sunto: Calcium carbonate is a ubiquitous mineral that represents one  of the most significant biominerals, a major contributor to carbon sequestration through  geological deposits, and a technological hindrance as a result of scale formation. Amorphous calcium carbonate is intimately involved in the nucleation and growth of this material, yet  much remains undiscovered regarding the atomic detail. Through dynamical simulation  we demonstrate that nucleation of amorphous calcium carbonate follows a nonclassical  pathway. This arises from the addition of ion pairs to clusters exhibiting a consistently exothermic free energy that persists with increasing particle size. Furthermore, the isruption of the surrounding water of solvation by the atomically rough surface reduces 
the barrier to growth to the order of ambient thermal energy, thereby allowing the amorphous phase to grow faster than crystalline polymorphs. Amorphous calcium carbonate nanoparticles are also found to exploit size-dependent water content to render itself  more stable than the favored bulk phase, calcite, below a critical diameter of close to 4 nm.

= Per informazioni: ==================================
prof. Luciano Colombo
Department of Physics - University of Cagliari
Cittadella Universitaria - 09042 Monserrato (Ca), ITALY
Phone +39 070 675 4871 - Fax +39 070 510 171
E-mail: luciano.colombo@dsf.unica.it
URL: http://www.dsf.unica.it/colombo
Skype ID: l.colombo