淡水三角帆蚌贝壳珍珠质的同步辐射XRD研究

Synchrotron XRD Study on the Nacre of Freshwater Bivalve H. cumingii Lea

利用同步辐射XRD研究淡水三角帆蚌贝壳珍珠质的内应力和珍珠质中单个文石板片的微结构,发现淡水三角帆蚌贝壳珍珠质中单个文石板片内存在晶内有机物,且该晶内有机物导致珍珠质层中产生拉应力.这一拉应力沿不同晶向呈现强烈的各向异性,表明晶内有机物在文石板片内很可能以某一特定的方式排列.同步辐射XRD图谱的线形分析进一步证实淡水三角帆蚌贝壳珍珠质中的晶内有机物吸附于文石板片的(002)晶面.这些研究结果将促进珍珠质矿化及强韧化机制的研究,为设计高性能无机有机复合材料及培育珍珠提供科学的根据.

Synchrotron XRD was used to study internal stress of nacre and microstructure of individual nacre tablet in the shell of freshwater bivalve H. cumingii Lea. The diffraction patterns show some biopolymers （intra-crystalline organic matrix） are occluded inside nacre tablets during biomineralization, causing that nacre powder exhibits tensile- like internal stress which is strongly anisotropic along different vectors of the reciprocal lattice. The characteristic of internal stress suggests that the intra-crystalline organic matrix is most probably arranged in the specific form. And line profile analysis which is conducted with the synchrotron XRD patterns of heated and unheated nacre powder samples, further confirms that the intra-crystalline organic matrix is adsorbed on （002） atomic planes of nacre tablets. The findings will facilitate the study on the formation mechanism and the strengthening and toughening mechanism of the nacre and provide theoretical basis for designing new organic-inorganic composite with high performances and cultivating pearl