NATURAL ORGANIC-INORGANIC COMPOSITE SYSTEMS

The aim of this study is the characterization of selected natural composite systems created as organic-inorganic materials. The study is focused on the characterization of the structure and chemical composition of these systems and on the evaluation of basic mechanical parameters of selected samples, too. The detailed description is presented for the structure of sea shells, which are created by interconnected layers of micron crystals and submicron plates of calcium carbonate. These systems were evaluated by scanning electron microscopy, EDX analysis and nanoindentation. The typical structure of nacre is known as a typical arrangement but the arrangement is different for other types of shells. Individual building blocks can also be found with the dimensions complying with the definition of nanostructured materials. The arrangement of the crystal exhibits a recurring motive - crystals are characterized by their shape, mostly pentagons and hexagons, but also their diameter, height and thickness. The difference between the layers as well as their interconnection is characteristic for different kinds of shells. The aim of the structure and the chemical composition study is to obtain all necessary information for constructing similar systems for use in practice.