Multiscale structure of sheet nacre.
This work was conducted on Pinctada maxima nacre (mother of pearl) in order to understand its multiscale ordering and the role of the organic matrix in its structure. Intermittent-contact atomic force microscopy with phase detection imaging reveals a nanostructure within the tablet. A continuous organic framework divides each tablet into nanograins. Their shape is supposed to be flat with a mean extension of 45nm. TEM performed in the darkfield mode evidences that at least part of the intracrystalline matrix is crystallized and responds like a 'single crystal'. The tablet is a 'hybrid composite'. The organic matrix is continuous. The mineral phase is thus finely divided still behaving as a single crystal. It is proposed that each tablet results from the coherent aggregation of nanograins keeping strictly the same crystallographic orientation thanks to a hetero-epitaxy mechanism. Finally, high-resolution TEM performed on bridges from one tablet to the next, in the overlying row, did not permit to evidence a mineral lattice but crystallized organic bridges. The same organic bridges were evidenced by SEM in the interlaminar sequence.
Rousseau
Marthe
M
Museum National d'istoire Naturelle, Département des Milieux et Peuplements Aquatiques, UMR 5178 : CNRS-MNHN: Biologie des Organismes Marins et Ecosystèmes, 7, rue Cuvier 75005 Paris, France.
Lopez
Evelyne
E
Stempflé
Philippe
P
Brendlé
Marcel
M
Franke
Loïc
L
Guette
Alain
A
Naslain
Roger
R
Bourrat
Xavier
X
D000818:Animals; D001672:Biocompatible Materials / Q000032:analysis* / Q000737:chemistry*; D003460:Crystallization / Q000379:methods*; D046911:Macromolecular Substances / Q000032:analysis / Q000737:chemistry; D008422:Materials Testing; D008968:Molecular Conformation; D008974:Mollusca / Q000737:chemistry*; D049329:Nanostructures / Q000032:analysis / Q000737:chemistry* / Q000648:ultrastructure*; D013499:Surface Properties; D014020:Tissue Extracts / Q000032:analysis* / Q000737:chemistry*
D001672:Biocompatible Materials; D046911:Macromolecular Substances; D014020:Tissue Extracts