Crystallographic control on the substructure of nacre tablets

摘要: Abstract Nacre tablets of mollusks develop two kinds features when either the calcium carbonate or organic portions are removed: (1) parallel lineations (vermiculations) formed by elongated rods, and (2) hourglass patterns, which appear in high relief etched low if bleached. In untreated tablets, SEM AFM data show that vermiculations correspond to aligned fused aragonite nanogloblules, partly surrounded thin pellicles. EBSD mapping surfaces indicates invariably crystallographic a-axis triangles with b-axis advance {0 1 0} faces during growth tablet. According our interpretation, because molecules expelled from a-axis, where Ca–CO3 bonds shortest. this way, subunits forming nacre merge uninterruptedly, chains whereas sides these chains. Hourglass patterns would be produced preferential adsorption along {0 1 0}, as compared {1 0 0} faces. A model is presented for nanostructure tablets. also existence within nanocrystalline units, twinned on {1 1 0} rest Our study shows dynamics (and bioaragonite general) results interaction at different mutually related levels: nanogranules.