Inhomogeneity of Nacre Lamellae on the Nanometer Length Scale
2012-09-05T00:00:00Z (GMT) by
We present experimental evidence of inhomogeneous distribution of organic inclusions within individual aragonitic lamellae forming the nacre layer of mollusk shells. This nanoscale-inhomogeneity is visualized in the Perna canaliculus (green mussel) shells by the aid of high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM) in the tomography mode. Electron tomography reconstructions of the three-dimensional distribution of intracrystalline organic inclusions, ranging in size between 2 to 25 nm, clearly reveal 50 nm wide depletion zones adjacent to the organic sheets between lamellae. The interrelation between the observed fine-scale inhomogeneity of nacre layer and its improved mechanical properties is discussed.