I've been writing an essay on biomimetic materials, only to discover that there really aren't very many. I've made the rule that to qualify the material must objectively use one or more mechanisms found in a biological material and must have a mechanical performance close to, or better than, the biological material. I discount medical scaffolds and prostheses on the grounds that they are either not up to the mechanical performance or are performing a structural task but not really working at the material level. Also, it can't simply be a remanufactured biological material. So although respinning silk dope is not a trivial task, a significant part of the problem has been solved in that it's known that the dope can form liquid crystalline structures., Similarly with casting films of collagen which show liquid crustalline structures. Both these products have excellent mechanical properties. The last criterion is that the materials must be able to be made in useful quantities. This is a bit more difficult to define further, since nanostructures can be quite useful!
The only ones I can find are two versions of nacre and one of wood. The nacre ones are by Bill Clegg, made some years ago (Clegg, W. J., Kendall, K., Alford, N. M., Button, T. W. and Birchall, J. D. (1990). A simple way to make tough ceramics. Nature 347, 455-457) and by Lars Berglund more recently (Walther, A., Bjurhager, I., Malho, J.-M., Ruokolainen, J., Berglund, L. A. and Ikkala, O. (2010). Supramolecular control of stiffness and strength in lightweight high-performance nacre-mimetic paper with fire-shielding properties. Angew. Chem. Int. Ed. 49, 1-7). The wood one was by George Jeronimidis even earlier (Gordon, J. E. and Jeronimidis, G. (1980). Composites with high work of fracture. Philosophical Transactions of the Royal Society A 294, 545-550; Chaplin, R. C., Gordon, J. E. and Jeronimidis, G. (1983). Development of a novel fibrous composite material. USA Patent No 4409274).
Are there any others?
Julian Vincent
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