Abalone Nacre

The dip coating method enabled the synthesis of nanocomposite silica film with the laminated structure of abalone nacre, which is known for its strength,... 

Figure 3. Fracture surface of abalone nacre (matrix removed).

The possibility raised by the work of Taylor and Layman that a polymeric matrix can raise the hardness of a composite material above that of its ceramic microphase has important potential in the design of such materials. Therefore, despite the unfavorable findings described above for abalone nacre, experiments were made to explore this possibility further. In the experiment in which the matrix of a specimen of nacre was replaced with crosslinked PMMA the hardness was little changed, from 149 + 9 to 144 + 12. However, this experiment was inconclusive because the replacement of the matrix was confined to a surface layer and results may have been influenced by... 

A) Influence of storage in vacuum on Knoop hardness number of abalone nacre. (B) Influence of y-irradiation on Knoop hardness number of abalone nacre. 

Fig. 2. Nacre of red abalone shell Halitotis refescens), imaged here by transmission electron microscopy (left), has a bricks-and-mortar structure. The bricks are CaCOs (aragonite) platelets, and the mortar is a composite of macromolecules, including structural proteins and polysaccharides, that form a thin film around the platelets. The three-dimensional structure is depicted on the right [23]...

Fig. 4.20. Scanning electron micrographs showing the dominant deformation mechanisms observed in nacre of abalone. (a) Frictional shding of aragonite platelets in the highly strained region surrounding an indentation. (6) Ligaments of organic material bridging the inter-platelet cracks. Reproduced with permission from Sarikaya et al (1995).

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