Solid-state phase transformation and self-assembly of amorphous nanoparticles into higher-order mineral structures.
Fiche publication
Date publication
juin 2020
Journal
Journal of the American Chemical Society
Auteurs
Membres identifiés du Cancéropôle Est :
Dr LAURENT Guillaume
Tous les auteurs :
Von Euw S, Azais T, Manichev V, Laurent G, Pehau-Arnaudet G, Rivers M, Murali N, Kelly DJ, Falkowski PG
Lien Pubmed
Résumé
Materials science has been informed by nonclassical pathways to crystallization based on biological processes to fabricate damage-tolerant composite materials. Various biomineralizing taxa, such as stony corals, deposit metastable, magnesium-rich, amorphous calcium carbonate nanoparticles that further assemble and transform into higher-order mineral structures. Here we examine a similar process in abiogenic conditions using synthetic, amorphous calcium magnesium carbonate nanoparticles. Applying a combination of high-resolution imaging and in situ solid-state nuclear magnetic resonance spectroscopy, we reveal the underlying mechanism of the solid-state phase transformation of these amorphous nanoparticles into crystals under aqueous conditions. These amorphous nanoparticles are covered by a hydration shell of bound water molecules. Fast chemical exchanges occur: the hydrogens present within the nanoparticles exchange with the hydrogens from the surface-bound H2O molecules which, in turn, exchange with the hydrogens of the free H2O molecule of the surrounding aqueous medium. This cascade of chemical exchanges is associated with an enhanced mobility of the ions/molecules that compose the nanoparticles which, in turn, allow for their rearrangement into crystalline domains via solid-state transformation. Concurrently, the starting amorphous nanoparticles aggregate, and form ordered mineral structures through crystal growth by particle attachment. Sphere-like aggregates and spindle-shaped structures were respectively formed from relatively low or high weights per volume of the same starting amorphous nanoparticles. These results offer promising prospects for exerting control over such a non-classical pathway to crystallization to design mineral structures that could not be achieved through classical ion-by-ion growth.
Référence
J. Am. Chem. Soc.. 2020 Jun 22;: