What is nanotechnology?

Nanotechnology is an applied science, whose purpose is to study the design method, composition, characteristics and application of materials and equipment on the nanometer scale. Nanotechnology is a technical sub-category in many scientific fields, such as biology, physics and chemistry. The National Nanotechnology Initiative of the United States defines it as "an object with the size of 1 to 100 nm, in which unique phenomena with great application value can be understood and manipulated."

Nanotechnology is a cutting-edge technology, but it has been around for a long time. For example, non-stick sludge is the characteristic of lotus surface. The fine structure and roughness of lotus surface are in the nanometer scale range, so it is not easy to absorb sludge and dust. It is natural for lotus to emerge from the mud without being stained, which is better than any cleaning technology of human beings. This nano-structure and self-cleaning physical phenomenon on the surface of lotus is called lotus effect.

Nanotechnology is the study of phenomena and the control of matter on the nanometer scale, especially the extension of the existing technology on the nanometer scale. The world of nanotechnology is a collection of atoms, molecules, polymers, quantum dots and polymers, which is dominated by surface effects, such as van der Waals force, hydrogen bond, charge, ionic bond, valence bond, hydrophobicity, hydrophilicity and quantum tunneling effect, while macro effects such as inertia and turbulence are too small to be ignored. For example, when the ratio of surface area to volume increases sharply, new possibilities of surface-based science such as catalytic chemistry appear.

The continuous exploration of the tiny leads to the birth of new tools, such as atomic force microscope and scanning tunneling microscope. Combined with precise procedures such as electron beam lithography, these devices will enable us to operate and generate nanostructures accurately. Whether nano-materials are made from top to bottom (the main way to reduce the block to nano-scale is to cut, etch and grind the block to get the smallest shape possible (for example, ultra-precision machining, the difficulty is that the obtained microstructure must be accurate). Or made from bottom to top (composed of atoms or molecules), the main methods are chemical synthesis, self-assembly and positional assembly. The difficulty lies in achieving high-efficient and stable quality on the macro level, not just further miniaturization. The quantization of the energy of electrons in an object has also begun to affect the properties of materials. This is the so-called quantum scale effect, which describes the physical properties of electrons in a substance after the scale is greatly reduced. This effect is not caused by the scale change from macro to micro, but it does occupy a very important position on the nanometer scale. When substances are at the nanometer scale, they will be very different from those at the macroscopic scale. For example, opaque substances will become transparent (copper), inert substances will become catalysts (platinum), stable substances will become flammable (aluminum), solids will become liquids (gold) at room temperature, and insulators will become conductors (silicon).

The magic of nanotechnology lies in its quantum and surface phenomena on the nanometer scale, so it may have many important applications and make many interesting materials.

Application of nanotechnology

Nanotechnology has been successfully applied in many fields, including medicine, pharmacy, chemical and biological detection, manufacturing, optics and national defense. This entry is the general outline of nanotechnology application, including the following fields: 1, nanotechnology application in new materials 2, nanotechnology application in microelectronics, electric power and other fields 3, nanotechnology application in manufacturing 4, nanotechnology application in biology, medicine and pharmacy 5, nanotechnology application in chemistry and environmental monitoring 6, nanotechnology application in energy, transportation and other fields 7, nanotechnology application in agriculture 8. Chemical fiber cloth is quite strong, but it has annoying static phenomenon, which can be eliminated by adding a small amount of metal nanoparticles. Using nano-materials, refrigerators can resist bacteria. Sterile tableware and aseptic food packaging products made of nano-materials have come out. By using nano-powder, wastewater can be completely turned into clean water, which fully meets the drinking standards. Nano food is full of color, fragrance and health. The application of nanotechnology can improve the washability of wall coatings by 10 times. Self-cleaning glass and self-cleaning tiles can be made by coating nano-thin layers on the surfaces of glass and tiles without scrubbing at all. Building materials containing nanoparticles can also absorb ultraviolet rays harmful to human body. Nanomaterials can improve the performance of vehicles. Nano-ceramics are expected to become ideal materials for engine parts such as automobiles, ships and airplanes, which can greatly improve the efficiency, working life and reliability of engines. Nanosatellites can provide drivers with traffic information at any time to help them drive safely. The micro drug delivery device made of nanotechnology can carry a certain dose of drugs and reach the focus accurately under the guidance of electromagnetic signals in vitro, which can effectively play a therapeutic role and reduce the adverse reactions of drugs. Micro robots made of nano-materials are smaller than red blood cells. By injecting them into patients' blood vessels, cerebral vascular thrombosis can be dredged. Remove fat and deposits from heart arteries, and also "chew" stones in the urinary system. Nanotechnology will be a good helper for a healthy life. The application prospect of nanotechnology is very broad, and the economic benefit is very huge. American authorities predict that the nanotechnology market will reach144 billion dollars in 20 10, and the application of nanotechnology will far exceed the computer industry in the future. Nano-composite, modification of plastics, rubber and fiber, design and application of nano-functional coating materials will inject new high-tech content into traditional production and products. Experts pointed out that a "material revolution" triggered by nanotechnology will inevitably occur in the fields of textiles, building materials, chemicals, petroleum, automobiles, military equipment and communication equipment. At present, nearly 65,438+000 companies in China have registered nanomaterials and nanotechnology, and more than 65,438+00 production lines for nanomaterials and nanotechnology have been established. Nano-fabrics and clothing have been mass-produced, such as computer work clothes, anti-static clothes, anti-ultraviolet clothes and so on. The new coating with nanotechnology not only improves the washability by more than ten times, but also is nontoxic, harmless and odorless. Nanotechnology is improving and improving people's quality of life.

Nanoscience and technology

Nano-science and technology mainly includes nano-system physics, nano-chemistry, nano-materials, nano-biology, nano-electronics, nano-processing, nano-mechanics and so on.

nanotechnology

Nanoscience and technology is a high-tech subject that studies the motion laws and characteristics of electrons, atoms and molecules in the space of 0. 1nm~ 100nm. Nano-science and technology covers nano-physics, nano-electronics, nano-materials, nano-mechanics, nano-manufacturing, nano-microscope, nano-metrology, nano-chemistry, nano-biology and nano-medicine. Nanotechnology was born on the basis of the combination of modern physics and advanced engineering technology, and it is a high-tech closely related to basic research and application exploration.

Nano antithrombotic Chinese medicine

Traditional Chinese medicine ingredients coated with lipophilic binary nano-synergistic interface will make cardiovascular and cerebrovascular diseases, the number one threat to human health, be treated more effectively, and will make traditional Chinese medicine, an important part of Chinese civilization, go global. Because such nano-Chinese medicine has millions of times the physical activity (therapeutic effect) of ordinary Chinese medicine, it can reach vascular embolism and tissue lesions caused by fat accumulation unimpeded, and dissolve with fat because of its affinity, and release the effective components of treatment at the same time, thus improving the targeting of drugs by millions of times.

Nano-porous membrane

Nano-porous membrane prepared by using binary synergistic nano-interface technology platform will completely solve the problem of deliquescence and shedding of paints and coatings, and can conveniently mass-produce nano waterproof coatings with respiratory function and nano ultrafiltration membranes with reverse dialysis function, which will bring revolutionary changes to human daily life and even seawater desalination technology and fundamentally solve the increasingly serious water shortage problem of human beings.

Nano-repair material

Using nanotechnology, we can also use new principles and new structures to build materials with specific properties or materials that do not exist in nature at the nano level, make biomaterials and bionic materials, and diagnose and repair the damage at the nano level during the process of material destruction. At present, nano-materials have been increasingly used in instruments, cosmetics, medicine, printing, paper making, electronics, communications, construction and military fields.

Nanometer self-cleaning surface treatment and coating

If transparent, oleophobic and hydrophobic nano-material particles are combined on the surface of buildings or on tiles and glass, buildings will not be polluted by oil in the air, and tiles and glass will always be transparent because they will not be stained with water vapor. Any substance attached to the surface, under the irradiation of sunlight, will become a vaporizable gas or a substance that can be easily erased under the catalysis of nano-coatings, so that buildings are no longer always dirty, and bathroom equipment in the family does not need to be cleaned every day. Put this nano-particle into the fabric fiber, and the clothes made will not be stained with dust, which saves a lot of trouble in washing clothes. The biggest ability of oxide nanoparticles is to quickly change color under the action of electric field or light irradiation. Ordinary people wear a color-changing mirror with a slow speed, but the color-changing mirror made of nano-materials is different, and it changes color quickly, so it is better as a protective laser mirror for soldiers.

Novel nano light source and solar energy converter

Billboards made of nano-oxide materials will become more colorful under the action of electricity and light. The biggest use of semiconductor nano-materials is that they can emit various colors of light, can be made into ultra-small laser light sources, and can also absorb the light energy in the sun and directly convert it into electric energy. Once this technology is realized, solar cars and solar houses will become a reality. By then, people's living environment will be better and the air will be fresher.

Nanosensor

Various sensors made of semiconductor nano-materials can sensitively detect the changes of temperature, humidity and atmospheric composition, and have been applied in automobile exhaust and atmospheric environmental protection. Nano-sensing system can be used for early diagnosis of diseases, and durable and human-friendly artificial tissues and organs and devices for vision and rehabilitation can be made by using nano-materials, thus improving the quality of life of patients.

Nano-oriented drugs and skin care products

If guided outside the human body, nano-drugs can be used to block capillaries and starve cancer cells, and the effect of drug treatment will be greatly improved. Nanoparticles can also be used for cell separation or cell staining in human body, and can also be used to carry DNA for gene defect treatment. If the nano-medicine is made into plaster and stuck on the affected area, the medicine can be absorbed directly through the skin without needle injection, thus reducing the infection caused by injection. Drugs or foods that are not easily absorbed by the human body, such as vitamins, are made into nano powder or nano powder suspension, which is easily absorbed by the human body.

Nano-machining technology

For the application of nano-scientific research and its achievements, it is necessary to cut and arrange materials freely at the nano-scale according to people's wishes. This technology is called nano-machining technology. In fact, on the one hand, nano-machining technology is an important foundation for the application of nano-materials, on the other hand, nano-machining technology also contains many nano-scientific problems that people have not yet understood clearly. For example, in a hole or wire several nanometers thick, the diffusion of atoms is very different from the macro world. Generally speaking, the free path of atomic motion is several microns. At this length, the collision and thermal diffusion of atoms can be ignored. However, in nanopores or nanowires, the diffusion of atoms is mainly accomplished by colliding with the pore wall. For another example, it is generally believed that the friction between objects in mutual movement mainly comes from the unevenness of the surface of the objects, that is, the smoother the surface of the objects, the smaller the friction between them. In the nano-world, the surface of materials is so small that the atoms on the surfaces of the two materials are so close that the atoms on the surfaces of the two materials will be chemically bonded, resulting in resistance to mutual movement. Therefore, in the nano-world, all processing technologies must be considered at the level of atomic size.

Nanoelectronic component

Nanomachining technology can integrate different materials. It has the function of a chip, which can detect electromagnetic wave and light wave (including visible light, infrared light and ultraviolet light) signals and execute computer instructions. If this integrated device is installed on the satellite, the weight of the satellite can be greatly reduced. At present, people are already considering using "Bird" satellite to partially replace the existing satellite system. If nano-integrated devices are used on satellites, the "Bird" satellite will be smaller, easier to launch and lower in cost.

Application of carbon nanotubes

Carbon nanotubes are a very unique material, and scientists all over the world are trying to study it. It is a cage-like "fiber" formed by curling one or several layers of carbon atoms in graphite, with a hollow inside and an outer diameter of only a few to several tens of nanometers.

This material is light but strong. Its density is 1/6 of steel, but its strength is 100 times of steel. It's best to use this light, soft and very strong material to make bulletproof vests. If carbon nanotubes are used as rope, it is the only rope that can be hoisted from the moon to the surface of the earth without being broken by its own weight. If it is used as an elevator from the earth to the moon, it will be easy for people to settle on the moon. The thin tip of nanotubes can easily emit electrons, which can be used as an electron gun and can be made into a wall-mounted TV screen with a thickness of several centimeters, which is a new direction of TV manufacturing.

Application of ultra-high physical activity nano-materials

Imagine that a "nanoparticle" only contains hundreds or thousands of atoms and molecules. According to general experience, the distance between atoms is about 0.2 nm. It can be estimated that in a cubic "particle" with the size of 1 nm, only five atoms can be arranged on each side, which can accommodate 125 atoms in total, but 98 of them are on the surface. As we know, the atoms on the surface are only influenced by atoms from the inside. Therefore, they can easily react with external gases, fluids and even solid atoms, which means that they are very active. Experiments show that if copper or aluminum is made into several nanoparticles, it will burn and explode when it meets air. Some people think that the solid fuel made of nano-particle powder will have greater thrust and can be used as solid fuel for new rockets and high explosives. In addition, the use of nano-metal particle powder as catalyst can accelerate the chemical reaction process and greatly improve the yield of chemical synthesis.

Nano-high strength material

If the metal nano-material particle powder is made into a block metal material, it will become very strong, ten times stronger than ordinary metal, and at the same time it can be as elastic as rubber. People fantasize that in the next century, nano-steel and nano-aluminum with such magical properties will be produced one day. The weight of cars, planes or ships made of this material will be reduced to110. By then, the weight of a motorcycle will become only 20 ~ 30 kilograms. The most commonly used ceramic materials in people's daily life are hard and brittle. It just means it can be used as a tool for cutting metal, and brittleness means it can't stand impact. Another advantage of ceramics is its high temperature resistance, which does not deform at the high temperature of 10000℃. At present, ceramics made of nano-ceramic powder have shown certain plasticity. Once this problem is completely solved, it will play a great role in the automobile engine, completely get rid of the engine cooling system, make the engine work at a higher temperature, the car will run faster and the plane will fly higher.

Nano-single electron element

If free-moving electrons are trapped in a small nanoparticle, or in a very thin short metal wire only a few nanometers wide, very wonderful things will happen. Because the movement of electrons in particles is limited, the electronic state that can continuously have any momentum below Fermi momentum becomes only a certain momentum value, that is, the electronic momentum or energy is quantized. The most direct result of free electron energy quantization is that a voltage is applied across the metal particles, and when the voltage is appropriate, the metal particles conduct electricity; When the voltage is inappropriate, the metal particles are not conductive. In this way, ohm's law, which is regarded as a classic in the macro world, is no longer valid in the nano world. There is another strange phenomenon. When the metal nanoparticles gain an extra electron from the external circuit, the metal particles are negatively charged, and its coulomb force is enough to repel the next electron from the external circuit to the metal particles, which cuts off the continuity of current, which reminds people whether an electronic device controlled by electrons can be invented, that is, a so-called single-electron device. The size of a single electronic device is very small. Once realized, by integrating them into computer chips, the capacity and computing speed of computers will be improved by millions of times.

Nano-laser and high-density information storage

In fact, the captured electrons are not so "honest". According to the laws of quantum mechanics, sometimes it can escape through the prison "wall". On the one hand, this phenomenon indicates that the logic units in the new generation of chips will have no wire connection, so a new design is needed to make a single electronic device into an integrated circuit. On the other hand, it will make the action of the chip uncontrollable. In the final analysis, in this case, electrons should be regarded as "waves" rather than particles. Therefore, although electronic devices have been realized in the laboratory, it will take time for them to be really used in industry. Another contribution of electrons trapped in small size is that they will make the material emit strong light. "Quantum dot array laser" or "cascade laser" is small in size, but its luminous intensity is high. They can be driven to emit blue light or green light with very low voltage, and the storage density of optical discs can be increased several times when used for reading and writing. If we use small quantum dots that "trap" atoms to store data and make quantum disks, the storage degree can be improved by thousands of times, which will bring a revolution to information storage technology.

Extended reading:

1265438+The first 20 years of the 20th century is a crucial period for the development of nanotechnology. Due to the special properties of nano-materials, the application of nano-technology and nano-materials in various fields of industrial production can bring about changes in product performance or improve performance to a great extent. Using nanotechnology to transform traditional industries, especially heavy industries, will bring new opportunities and have great room for expansion. After the development from scratch, nanotechnology has initially formed a large-scale industry. Affected by the international financial crisis, the development of nano-material technology and the sales speed of products have slowed down. At the same time, due to the potential negative impact on human health and the environment, the development of this industry may slow down, but the market scale of nano-materials will be considerable in the future. By 20 15, the global sales of nanotechnology and products will reach $2.5 trillion. The economic recession has the greatest impact on the automobile, construction and some electronic industries, but it is not expected to have much impact on health care and life sciences. Among nanomaterials, carbon nanotubes and ceramic nanoparticles are widely used in automobile and construction industries, so they are greatly affected by economic recession. Among the nano-intermediates, the fields of nanocomposites and coatings are most affected by the economic downturn. Compared with the United States and Europe, the sales of composite nanotechnology products have increased rapidly in the Asia-Pacific region. The United States and Europe account for more than two-thirds of all nano-materials sales, but by 20 15, their market share will drop by 2-3%.