In real life, we have come into contact with many animals and plants, all of which belong to the category of biology. All living things on the earth are made of ideal inorganic or organic substances. Materials used by animals and plants to cast bodies include cellulose, lignin, chitin, protein and nucleic acid. Their structures are very complicated. Some structural materials of many living things are completely unknown to us. Most of these materials are formed at normal temperature and pressure, which can play a unique role. When people fully understand these biological phenomena, they are applied to material science and technology, that is, bionic materials.
Function:
1 One of the earliest bionic materials that was successfully studied was the man-made fiber that imitated the contact feeling between natural fiber and human skin. People have been interested in silkworms or spiders since ancient times. These silks are made in protein, especially silk, which has a warm touch and beautiful luster. Since the 20th century, people have developed various spinning methods of chemical fibers by imitating the spinning process of silkworm, and then developed many new fibers by imitating the wearability of biological fibers, such as milk protein, acrylic fiber, acrylic * * * poly fiber (Toyo Spinning), and the trade name is sparse high hygroscopicity fiber (Asahi Kasei Chemical). The appearance of these products shows that human beings have successfully imitated the fine surface morphology and internal structure of biological fibers. In addition, people have also conducted fruitful research on the silk body of silkworm (Japan Institute of Agricultural Biological Resources) and spider silk (Shimane University, Japan), and researchers are looking forward to making rayon exactly like silk one day.
Animals living on land have lungs, which can separate oxygen in the air, and fish in water have gills, which can separate oxygen dissolved in water and supply it to the body. Imitating this characteristic, people made thin film materials to produce high concentration oxygen and separate ultra-pure water, so as to save energy and achieve the purpose of high separation rate. At present, people are developing materials with functions of animal lungs and fish gills. If they are successfully developed, a new revolution will take place in human activities in the underwater world.
In order to maintain life, organisms can convert all kinds of energy very efficiently, which is a phenomenon that can be seen in the vast biological world. For example, people have studied the luminous mechanism of fireflies, which is due to the efficient conversion of chemical energy into light energy. Although human beings have experienced the charm of nucleic acid, the key of genetic information, in the field of chemistry, and great progress has been made in the research of realizing its function in test tubes, this kind of energy transformation like fireflies is currently impossible for human beings. With the gradual depletion of energy used on the earth, human beings urgently need to seek new energy sources. If we can find materials and methods that can efficiently convert or recombine energy, like some creatures, it will bring hope and light to the future of mankind.
Eggs are the largest cells in animals born in vitro by birds and reptiles. Its shell is calcareous, with egg white and yolk inside. Finks, an American scholar, published an interesting hypothesis that the structure of eggs has a lot to learn from both mechanical and engineering perspectives, and the packaging technology of human beings is dwarfed by it. The formation process of eggshell, like the development process of teeth and bones, is called calcification process, which is related to inorganic and organic interface chemistry. According to related reports, people are studying an artificial bone. It is believed that in the near future, through the research on the molding technology of organic-inorganic composite materials, people will not only learn and adopt the molding method of biological eggshells in packaging technology, but also open up new fields in medicine.
Plants also provide us with many interesting phenomena. For example, our common watermelon is a kind of fruit with high water content. Inspired by it, people developed a super absorbent resin similar to watermelon cellulose. It is made of specially designed polymer materials, which can absorb hundreds to thousands of times more water than its own weight. Now it has been used to recover waste oil, which is economical and efficient. If this material is further improved, the packaging and transportation of liquids in the future may be replaced by a brand-new technology. For example, in the future, drinks will no longer be packed in cups, but only a piece of film.
Plants also have many unique charms in the mechanical properties of composites. For example, from the cross section of bamboo, a kind of tissue called fiber bundles is densely distributed on the surface of bamboo, but the interior of bamboo is very rare, forming a high-strength composite material. However, when bamboo is still a bamboo shoot, this fiber bundle is evenly distributed on the cross section of the bamboo shoot. With the growth of bamboo shoots, the fiber bundles gradually move outward and finally form the best structure. For another example, tree rings are formed by different growth in winter and summer. These processes, which can grow directionally and form high-strength composite materials, have inspired people. Recently, there has been a trend to develop such oriented composites in the polymer world, which is certainly not an easy task. But this growing composite will also be one of the future research directions of composite materials.
Finally, touch the leaves of mimosa with your hands, and it will shrink like an animal. Inspired by this, Ueda of Olympus Company in Japan developed an endoscope that can be inserted into the small intestine. He used an elastic membrane material similar to the surface structure of mimosa leaves in the cylindrical part of the endoscope, which will automatically stretch or bend along the axis under the pressure of intestinal juice, thus keeping the cylindrical part of the endoscope in the same shape as the intestine.
To sum up, bionic materials use artificial polymer materials to imitate the functions from cells to fibers to various organs to the whole organism.