1. Natural nanomaterials
Sea turtles lay eggs on the coast of Florida in the United States, but young sea turtles after birth have to swim to the waters near the United Kingdom to survive and grow up in order to find food. Finally, the turtle will return to the coast of Florida to lay eggs. It takes about 5 to 6 years to go back and forth. Why can sea turtles travel tens of thousands of kilometers? They rely on nano magnetic materials in their heads to guide them accurately.
When biologists study why pigeons, dolphins, butterflies, bees and other creatures never lose their way, they also find that nano materials also exist in these organisms to guide them.
2. Nanometer magnetic material
Most of the nanomaterials used in practice are manufactured artificially. Nanomagnetic materials have very special magnetic properties. Nanoparticles are small in size, with single magnetic domain structure and high coercivity. Magnetic recording materials made of nano magnetic materials not only have good sound quality, image and signal to noise ratio, but also have good recording density ratio γ- Fe2O3 is dozens of times higher. The superparamagnetic strong magnetic nanoparticles can also be made into magnetic liquids, which can be used in electroacoustic devices, damping devices, rotary seals, lubrication, mineral processing and other fields.
3. Nano ceramic materials
In traditional ceramic materials, the grains are not easy to slide, the material is brittle, and the sintering temperature is high. The grain size of nano ceramics is small, and the grains are easy to move on other grains. Therefore, nano ceramic materials have extremely high strength, high toughness and good ductility, which enable nano ceramic materials to be cold worked at room temperature or sub high temperature. If the nano ceramic particles are processed and formed at sub high temperature, and then the surface is annealed, the nano material can become a high-performance ceramic with the surface maintaining the hardness and chemical stability of conventional ceramic materials, while the interior still has the ductility of nano materials.
4. Nano sensor
Nano zirconia, nickel oxide, titanium dioxide and other ceramics are very sensitive to temperature change, infrared ray and automobile exhaust. Therefore, they can be used to make temperature sensors, infrared detectors and automobile exhaust gas detectors. The detection sensitivity is much higher than that of ordinary similar ceramic sensors.
5. Nano tilt functional materials
In the hydrogen oxygen engine for aerospace, the inner surface of the combustion chamber needs to be resistant to high temperature, and its outer surface needs to contact with the coolant. Therefore, the inner surface should be made of ceramics, and the outer surface should be made of metal with good thermal conductivity. However, blocky ceramics and metals are difficult to combine. If the composition of metal and ceramic is gradually and continuously changed during fabrication, so that metal and ceramic "have me in you, and I have you in me", they can finally be combined to form a tilted functional material, which means that the composition changes in them like a tilted ladder. When metal and ceramic nano particles are mixed and sintered according to the requirements of gradual change of their content, they can meet the requirements of high temperature resistance on the side of the combustion chamber and good thermal conductivity on the outside.
6. Nano semiconductor materials
Silicon, gallium arsenide and other semiconductor materials are made into nanomaterials, which have many excellent properties. For example, the quantum tunneling effect in nano semiconductors makes the electronic transport of some semiconductor materials abnormal, and the conductivity decreases. The electrical thermal conductivity also decreases with the decrease of particle size, even negative. These characteristics play an important role in the field of large-scale integrated circuit devices, optoelectronic devices and so on.
Semiconductor nano particles can be used to prepare new solar cells with high photoelectric conversion efficiency, which can work normally even in rainy days. Because the electrons and holes generated by nano semiconductor particles when exposed to light have strong reduction and oxidation capabilities, it can oxidize toxic inorganic substances, degrade most organic substances, and finally generate non-toxic and tasteless carbon dioxide, water, etc., so it can use solar energy to catalyze the decomposition of inorganic substances and organic substances with the help of semiconductor nano particles.
7. Nanocatalytic materials
Nanoparticles are an excellent catalyst, which is due to their small size, large volume fraction on the surface, different chemical bond state and electronic state on the surface from those inside the particles, and incomplete coordination of surface atoms, leading to the increase of active sites on the surface, making them have the basic conditions to be used as catalysts.
Nanoparticles of nickel or copper zinc compounds are excellent catalysts for hydrogenation of some organic compounds, which can replace expensive platinum or palladium catalysts. Nanometer platinum black catalyst can reduce the temperature of ethylene oxidation reaction from 600 ℃ to room temperature.
8. Medical applications
The size of red blood cells in the blood is 6000 ～ 9000 nm, while the nano particles are only a few nanometers in size, which is actually much smaller than red blood cells, so they can move freely in the blood. If a variety of therapeutic nanoparticles are injected into various parts of the human body, the lesions can be examined and treated, which is better than traditional injections and medicines.
The blood compatibility of carbon materials is very good. In the 21st century, artificial heart valves are made by depositing a layer of pyrolytic carbon or diamond-like carbon on the material substrate. However, this deposition process is relatively complex, and generally only applicable to the preparation of hard materials.
Interventional air bags and catheters are generally prepared from highly elastic polyurethane materials. By introducing carbon nanotube materials with high aspect ratio and pure carbon atoms into highly elastic polyurethane, we can make this polymer material maintain its excellent mechanical properties and easy processing and molding characteristics on the one hand, and obtain better blood compatibility on the other hand.
The experimental results show that the degree of hemolysis caused by this nanocomposite will be reduced, and the degree of platelet activation will also be reduced.
Using nanotechnology can make the drug production process more and more refined, and directly use the arrangement of atoms and molecules to manufacture drugs with specific functions on the scale of nanomaterials. Nanometer material particles will make the transportation of drugs in the human body more convenient. After smart drugs wrapped with several layers of nano particles enter the human body, they can actively search and attack cancer cells or repair damaged tissues. New diagnostic instruments using nanotechnology can diagnose various diseases through protein and DNA in a small amount of blood. Through the special properties of nanoparticles, the surface of nanoparticles is modified to form some drug delivery carriers with targeted, controlled release and easy detection, which provide new methods for the treatment of local lesions in the body and open up a new direction for drug development.
9. Nanocomputer
The first electronic computer in the world was born in 1945. It was jointly developed by American universities and the Army Department. It used 18000 electronic tubes in total, with a total weight of 30 t and an area of 170 m2. It can be regarded as a giant. However, it can only complete 5000 operations in 1 s.
After half a century, computer technology has developed rapidly due to the development of integrated circuit technology, microelectronics, information storage technology, computer language and programming technology. Today's computer is small and exquisite. It can be placed on a computer table. Its weight is only one ten thousandth of that of the old ancestors, but its computing speed is far faster than that of the first generation of electronic computers.
If nanotechnology is used to build the components of electronic computers, the computer of the future will be a "molecular computer", which is far more compact than today's computers, and will also bring considerable benefits to society in terms of saving materials and energy.
The card reader that can read the hard disk and the nano material memory chip with a storage capacity of thousands of times of the chip have been put into production. After widely using nano materials, computers can be reduced to "handheld computers".
10. Carbon nanotube
In 1991, Japanese experts prepared a kind of material called "carbon nanotube", which is a tube composed of many hexagonal circular carbon atoms or several coaxial tubes. Both ends of such single-layer and multi-layer tubes are often sealed, as shown in Figure 1.
The diameter and length of such tubes composed of carbon atoms are of nanometer scale, so they are called carbon nanotubes. Its tensile strength is 100 times higher than that of steel, and its conductivity is higher than that of copper.
In the air, the carbon nanotube is heated to about 700 ℃, so that the carbon atoms at the seal on the top of the tube are destroyed by oxidation and become an open carbon nanotube. Then, low melting point metals (such as lead) are evaporated by electron beam and condensed on the open carbon nanotube. Due to the siphon effect, the metal enters the hollow core of the carbon nanotube. Because the diameter of carbon nanotubes is very small, the metal wires formed in the tubes are also very thin, called nanowires. The size effect it produces is superconductivity. Therefore, carbon nanotubes plus nanowires may become a new type of superconductor.
Nanotechnology is still in its infancy in countries around the world. Although the United States, Japan, Germany and other countries have begun to have a foundation, they are still studying, and new theories and technologies are still emerging. China has made great efforts to catch up with the level of advanced countries, and the research team is growing.
11. Home Appliances
The multifunctional nano material plastic made of nano materials has the functions of antibacterial, deodorizing, anti-corrosion, anti-aging, anti ultraviolet, etc. It can be used as the antibacterial and deodorizing plastic in the refrigerator and air conditioner shells.
12. Environmental protection
Nanofilms with unique functions will appear in the field of environmental science. The membrane can detect the pollution caused by chemical and biological agents, and can filter these agents to eliminate the pollution.
13. Textile industry
By adding nano SiO2, nano ZnO and nano SiO2 composite powder materials into the synthetic fiber resin, after spinning and weaving, the underwear and clothing can be made into bactericidal, mildew proof, deodorant and ultraviolet radiation resistant underwear and clothing, can be used to manufacture antibacterial underwear and supplies, and can be made into ultraviolet radiation resistant functional fibers that meet the requirements of national defense industry.
14. Machinery industry
Using nano material technology to coat the metal surface of key mechanical parts with nano powder can improve the wear resistance, hardness and service life of mechanical equipment.