Arrangement of intra-crystalline organic matrix in nacre from red abalone: A view by high-resolution synchrotron powder diffraction combined with SEM observation

Abstract

In the present study, we combine high-resolution synchrotron powder diffraction with SEM to shed additional light on the arrangement of an intra-crystalline organic matrix in the nacre from red abalone. SEM observation and synchrotron diffraction analysis show that an intra-crystalline organic matrix exists inside nacre tablets and is adsorbed on the (002) atomic plane in an isolated form. Most probably, the intra-crystalline organic matrix is nacrein and its atomic groups are connected with the (012) atomic plane. The findings provide a new understanding of the arrangement of intra-crystalline organic matrices and may facilitate studies on the formation mechanism and the strengthening and toughening mechanism of the nacre. It is worth pointing out that the new experimental method in this present paper can be extended to nanostructural research of other biominerals.