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INTELLIGENTS MATERIALS
Nature & Technology


Currently, many scientists are studying the structure of natural materials and using them as models in their own research, simply because these structures possess such sought-after properties as strength, lightness and elasticity. For example, the inner shell of the abalone is twice as resistant as the ceramics that even advanced technology can produce. Spider silk is five times stronger than steel, and the adhesive that mussels use to moor themselves to rocks maintains its properties even underwater. (1)

Gulgun Akbaba, a member of the Turkish Science and Technology Magazine research and publication group, speaks of the superior characteristics of natural materials and the ways in which we can make use of them:

Traditional ceramic and glass materials have become unable to adapt to new technology, which improves almost with every passing day. Scientists are [now] working to fill this gap. The architectural secrets in the structures in nature have slowly begun to be revealed… In the same way that a mussel shell can repair itself or a wounded shark can repair damage to its skin, the materials used in technology will also be able to renew themselves. These materials are harder, stronger, more resistant and possess superior physical, mechanical, chemical and electromagnetic properties. When leaving and entering the earth's atmosphere, for example, rockets, space stations, and research satellites need to possess lightness and the ability to withstand high temperatures. Work on the giant supersonic passenger carriers planned for intercontinental travel also requires light, heat-resistant materials. In medicine, the production of artificial bone requires materials that combine rubbery consistency with hard structure, and tissue as close as possible to that found in nature. (2)

To produce ceramic, used for a wide range of purposes from construction to electrical equipment, temperatures greater than 1,000-1,500 degrees are generally needed.

Several ceramic materials exist in nature, yet such high temperatures are never used to create them. A mussel, for instance, secretes its shell in a perfect manner at only 4 degrees Centigrade. This example of nature's superior creation drew the attention of Turkish scientist Ilhan Aksay, who turned his thoughts to wondering how we might produce better, stronger, useful and functional ceramics. Examining the internal structures of the shells of a number of sea creatures, Aksay immediately noticed the extraordinary properties of abalone shells. On the subject, he has this to say:

Magnified 300,000 times with an electron microscope, the shell resembles a brick wall, with calcium carbonate “bricks” alternating with a protein “mortar.” Despite calcium carbonate's essentially brittle nature, the shell is extremely strong due to its laminated structure and less brittle than man-made ceramics. Its lamination helps keep cracks from propagating, in roughly the same way that a braided rope doesn't fail when one single strand breaks. (3)

Inspired by such models, Aksay developed a very hard, resistant metallic ceramic of aluminum-boron carbide material. After being tested in various US Army laboratories, this material was used as armor plating for tanks! (4)

In order to produce biomimetic materials, today's scientists are carrying out research at the microscopic level. As one example, Professor Aksay points out that the bioceramic-type materials in bones and teeth are formed at body temperature with a combination of organic materials such as proteins, and yet possess properties much superior to those of man-made ceramics. Encouraged by Aksay's thesis that natural materials' s superior properties stem from connections at the nanometric level (one-millionth of a millimeter), many companies aiming to produce micro-tools at these dimensions have embarked on bio-inspired materials—that is, artificial substances inspired by biological ones. (5)

All too many industrial products and by products, produced under conditions of high pressures and temperatures, contain harmful chemicals. Yet nature produces similar substances under what might be described as “life-friendly” conditions—in water-based solutions, for example, and at room temperature. This represents a distinct advantage for consumers and scientists alike. (6)

Producers of synthetic diamonds, designers of metal alloys, polymer scientists, fiber optic experts, producers of fine ceramic and developers of semi-conductors all find applying biomimetic methods to be the most practical. Natural materials, which can respond to all their needs, also display enormous variety. Therefore, research experts in various fields—from bullet-proof vests to jet engines—imitate the originals found in nature, replicating their superior properties by artificial means.

Man-made materials eventually crack and shatter. This requires replacement or repairs, carried out with adhesives, for instance. But some materials in nature, such as the mussel's shell, can be repaired by the original organisms. Recently, in imitation, scientists have begun development on substances such as polymers and polycyclates, which can renew themselves. In the search to develop strong, self-renewing bio-inspired materials, one natural substance taken as a model is rhinoceros horn. In the 21 st century, such research will form the basis of material science studies. (7)

References:

1. David Perlman, “Business and Nature in Productive, Efficient Harmony,” San Francisco Chronicle , November 30, 1997, p. 5; http://www.biomimicry.org/reviews_text.html
2. Ilhan Aksay, “Malzeme Biliminin Onderlerinden,” (A leading figure in material science) Bilim ve Teknik (Science and Technology Magazine), TUBITAK Publishings, February 2002, p. 92.
3. Billy Goodman, “Mimicking Nature,” Princeton Weekly , Feature-January 28, 1998; http://www.princeton.edu/~cml/html/publicity/PAW19980128/0128feat.htm
4. Ilhan Aksay, “Malzeme Biliminin Onderlerinden,” (A leading figure in material science) Bilim ve Teknik (Science and Technology Magazine), TUBITAK Publishings, February 2002, p. 93.
5. Ilhan Aksay, “Malzeme Biliminin Onderlerinden,” (A leading figure in material science) Bilim ve Teknik (Science and Technology Magazine), TUBITAK Publishings, February 2002, p. 93.
6. Julian Vincent, “Tricks of Nature”, New Scientist , August 17, 1996, vol. 151, no. 2043, p. 38.
7. Ilhan Aksay, “Malzeme Biliminin Onderlerinden,” (A leading figure in material science) Bilim ve Teknik (Science and Technology Magazine), TUBITAK Publishings, February 2002, p. 93.

 
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