title: Multiscale structure of sheet nacre.
abstract: 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.
authors.affiliation: 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.
authors.forename: Marthe
authors.initials: M
authors.lastname: Rousseau
authors.forename: Evelyne
authors.initials: E
authors.lastname: Lopez
authors.forename: Philippe
authors.initials: P
authors.lastname: Stempflé
authors.forename: Marcel
authors.initials: M
authors.lastname: Brendlé
authors.forename: Loïc
authors.initials: L
authors.lastname: Franke
authors.forename: Alain
authors.initials: A
authors.lastname: Guette
authors.forename: Roger
authors.initials: R
authors.lastname: Naslain
authors.forename: Xavier
authors.initials: X
authors.lastname: Bourrat
mesh_terms: 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*
chemical_list: D001672:Biocompatible Materials; D046911:Macromolecular Substances; D014020:Tissue Extracts