Is nanometer a material or is it processed into nanometer?

Introduction: Many people may have heard of the word "nano", but many people may not know what is nano and what is nano-material. This paper mainly introduces the research status and development prospect of nano-materials, and believes that with the development of science and technology, more and more nano-materials will enter people's lives and benefit mankind.

Nanometer is the transliteration of English namometer, which is the unit of measurement in physics. 1 nanometer is one billionth of 1 meter; It is equivalent to the length of 45 atoms arranged together. In layman's terms, it is equivalent to one tenth of the thickness of hair. Just like millimeters and microns, nano is a concept of scale and has no physical connotation. When a substance reaches the nanometer scale, which is about 1- 100 nanometer, the properties of the substance will suddenly change and special properties will appear. This kind of material with special properties different from the original atoms, molecules and macroscopic substances is called nano-material. If only nano-scale materials have no special properties, they cannot be called nano-materials. In the past, people only paid attention to atoms, molecules or cosmic space, and often ignored this intermediate field, which actually exists in nature in large quantities, but did not realize the performance of this scale range before. Japanese scientists were the first to truly recognize its characteristics and introduce the concept of nano. In 1970s, they prepared ultramicro ions by evaporation, and found that a kind of conductive copper-silver conductor lost its original properties after being made into nano-scale, neither conducting electricity nor conducting heat. The same is true of magnetic materials, such as iron-cobalt alloys. If the size is about 20-30 nanometers, the magnetic domain will become a single magnetic domain, and its magnetism will be 1000 times higher than the original. In the mid-1980s, people formally named this kind of materials as nanomaterials.

In the dynamic 2 1 century, the rapid development of information, biotechnology, energy, environment, advanced manufacturing technology and national defense will inevitably put forward new requirements for materials, and the demand for materials for miniaturization, intelligence, high integration, high-density storage and ultra-high-speed transmission of components will be less and less. Aerospace, new military equipment and advanced manufacturing technology require higher and higher material properties. Innovation of new materials, and new technologies induced on this basis. The innovation of new products will be the most influential strategic research field of social development, economic revitalization and national strength enhancement in the next 10 year, and nano-materials will be one of the key materials to play an important role. Nanomaterials and nanostructures are the most dynamic research objects in the field of new materials, which have a very important impact on the future economic and social development, and are also the most active and close fields in the application of nanotechnology. In recent years, remarkable achievements have been made in nanomaterials and nanostructures. For example, the advent of magnetic nanorod array quantum disks with storage density of 400 grams per square centimeter, high-efficiency nano-array lasers with low cost and adjustable luminous band, nano-structured solar cells and thermoelectric conversion elements with low price and high energy conversion, and ablation-resistant high-strength and high-toughness nano-composite materials used as rail guns and rails have fully demonstrated their great application potential in new pillar industries and high-tech fields of the national economy. As American scientists have estimated, "this tiny substance that people can't see with the naked eye is likely to bring a revolution to various fields." The application of nano-materials and nano-structures will provide new opportunities for how to adjust the layout of pillar industries of the national economy, design new products, form new industries and transform traditional industries to inject high-tech content. The scientific significance of studying nano-materials and nano-structures lies in that it opens up a new realm for people to understand nature and is the source of knowledge innovation. Because the scale of nanostructure unit (1 ~ 100 μm) is equivalent to many characteristic lengths in matter, such as the de Broglie wavelength of electrons, the coherence length of superconductivity, the thickness of tunneling barrier and the critical size of ferromagnetism, the physical and chemical characteristics of nanomaterials and nanostructures are different from microscopic atoms and molecules and macroscopic objects, thus improving people's ability to explore nature and create knowledge. Discovering new phenomena, understanding new laws, putting forward new concepts and establishing new theories in the field of nano-materials will lay a foundation for building a new framework for the scientific system of nano-materials, and will also greatly enrich the research connotation in new fields such as nano-physics and nano-chemistry. At the turn of the century, high-toughness nano-ceramics and super-strong nano-metals are still important research topics in the field of nano-structure design of nano-materials, heterogeneous, heterogeneous and the combination of different nano-elements (zero-dimensional nanoparticles, one-dimensional nanotubes, nanorods and nanowires). The surface modification of nano-scale elements has become a new hotspot in the research of nano-materials, and people can synthesize new materials with special properties more freely according to their own wishes. Using new physical properties, new principles and new methods to design nanostructured devices and modify traditional nanocomposites is gestating new breakthroughs. 1 shape and trend research The nanotechnology generated in the preparation and application research of nanomaterials is likely to become the dominant technology in the first 20 years of the next century, thus driving the development of nano-industry. At the turn of the century, all advanced countries in the world have rearranged their research on nanomaterials from the perspective of future development strategies. At the critical moment at the turn of the century, it is very important to meet the new challenges, seize the project of nano-materials and cypress structure, and quickly organize scientific and technological personnel to carry out research around the goals set by the state. The achievements of the country where nano-materials were born in recent years and its influence and penetration in various fields have always attracted much attention. In the 1990s, the connotation of nano-materials research has been continuously expanded, and the field has been gradually broadened. An outstanding feature is that basic research and applied research are closely linked, the transformation speed of laboratory results is unexpected, and both basic research and applied research have made important progress. Nano-cu materials with grain size of 50urn have been successfully prepared in the United States, and the hardness is five times higher than that of coarse-grained cu. The yield stress of palladium with grain size of 7urn is five times that of coarse-grained palladium. Plasticization of high-strength intermetallic compounds has always attracted people's attention, and nanocrystallization of grains brings hope to solve this problem. According to the development trend of nano-materials and its important position in the development of high technology in the century, the governments of developed countries in the world are deploying research plans of 10 to 15 nano-technology. 1998, the National Foundation of the United States (NSF) invited the national scientific and technological circles to bid for the synthesis, processing and application of nano-functional materials as an important basic research project. Nanotechnology is also an important research object in several projects of darpa (National Advanced Technology Research Department) in the United States. In recent years, Japan has made various plans for the research of nanotechnology, such as ogala plan, erato plan, and the basic principle and device utilization research plan of quantum functional devices. 1997 investment in nanotechnology1280,000 USD. The German Ministry of Science and Technology has helped the federal government to make plans for developing nanotechnology from 1995 to 20 10 and 15. The British government has invested a lot of money in the research of nanotechnology; 1.997 western European investment1.200 million USD. According to the latest report of1July 8, 999 in Nature, the application potential of nano-materials has attracted the attention of the White House. US President Bill Clinton personally asked about the research of nano-materials and nano-technology, and decided to increase investment, and the financial support will increase from $250 million to $500 million in the next three years. This shows that the research upsurge of nano-materials and nano-structures will continue to develop in the next century. 2 International Trends and Development Strategies1On July 8, 1999, Nature magazine (400 volumes) published an important news entitled "The US government plans to increase investment to support the rise of nanotechnology". In this article, it is reported that the US government has increased its investment in nanotechnology research from $250 million to $500 million within three years. President Clinton will submit a bill supporting nanotechnology research to Congress for approval in February next year. In order to accelerate the research of nano-materials and technologies in the United States, the White House took temporary emergency measures to increase the funding intensity from the original $654.38+$97 million to $250 million. American Businessweek reported on August 19 that 265438+ 10 years ago, the American government decided to list nanotechnology research as one of the key areas, and American Businessweek listed nanotechnology as three areas that may make important breakthroughs in the 2 1 century (the other two are. At the critical moment when the 20th century is coming to an end, the White House suddenly paid so much attention to nano-materials and technologies for two reasons: First, the German Ministry of Science and Technology made a forecast on the market of nano-technology in 20 1996, which was estimated to reach1440 billion US dollars, and the United States tried to occupy a considerable share in such an attractive market. Williams, head of basic research in the United States, said: the original application of nanotechnology far exceeds the computer industry. The White House Office of Strategic Planning also believes that nanomaterials are the most important part of nanotechnology. In the report of Nature, it is particularly mentioned that the United States has led the world trend in nano-structure assembly system and the preparation and synthesis of nanoparticles with high specific surface area, ranking first in the world in the design and modification of nano-functional coatings and the application of nano-materials in biotechnology, and nano-sized components and nano-solids will also compete with Japan. 1999 In July, UCLA and Hewlett-Packard Company successfully developed the 100urn chip, and the University of Minnesota and Princeton University successfully prepared the quantum disk in 1998. This disk is a nano-array system composed of magnetic nanorods, and the density of 100 bit/s reaches 109 bit/. 1988, the French first discovered the giant magnetoresistance effect. By 1997, nanostructured devices based on giant magnetoresistance have been developed in the United States, which will have important application prospects in magnetic storage, magnetic memory, computer read-write head and so on. Recently, the research department of Kodak Company in the United States has successfully developed a new nano-powder with both pigment and molecular dye functions, which is expected to bring revolutionary changes to color rubber printing. Nano-powder materials are likely to inject new high-tech content into traditional industries and products in the modification of rubber, pigments and ceramic products, and will occupy an important share in the future market. The application of nano-materials in medicine has also attracted people's attention. It is these studies that make the White House realize that nano-materials and technologies will occupy an important strategic position. The second reason is that the field of nanomaterials and technology is the source of knowledge innovation and technological innovation. The discovery of new laws, new principles and the establishment of new theories provide new opportunities for basic science, and the United States plans to monopolize the "boss" position of basic research in this field. 3 Domestic research progress The research of nano-materials in China began in the late 1980s. During the Eighth Five-Year Plan period, "Nanomaterials Science" was included in the national climbing plan. The National Natural Science Foundation of China, China Academy of Sciences and State Education Commission have organized eight major and key projects respectively, and organized relevant scientific and technical personnel to work in various branches of nanomaterials. The National Natural Science Foundation has also funded more than 20 projects, and the national "863" theme of new materials has also started the research on high-tech innovation of nano-materials. After 1996, the application research of nano-materials showed gratifying signs. With the intervention of local governments and some entrepreneurs, the research of nano-materials in China has entered a new situation in which basic research drives applied research. At present, there are more than 60 research groups in China, and more than 600 people are engaged in the basic and applied research of nanomaterials. Among them, the units that undertook major national basic research projects and carried out nano-materials research earlier are: Shanghai Institute of Silicate, China Academy of Sciences, and Nanjing University. Basic and applied research on nanomaterials has also been carried out by the Institute of Solid Physics of China Academy of Sciences, Institute of Metals, Institute of Physics of China University of Science and Technology, Institute of Chemistry of Chinese Academy of Sciences, Tsinghua University, Jilin University, Northeastern University, Xi Jiaotong University, Tianjin University, Qingdao Institute of Chemical Technology, East China Normal University, East China University of Science and Technology, Zhejiang University, Dalian Institute of Chemical Physics of Chinese Academy of Sciences, Changchun Institute of Applied Chemistry, Changchun Institute of Physics and Institute of Photosensitive Chemistry. 10 years, the basic research of nano-materials in China has achieved remarkable and important research results. Many physical and chemical methods have been used to prepare nano-powders of oxides, nitrides, carbides and other compounds of metals and alloys (crystalline, amorphous and nanocrystalline), and corresponding equipment has been established to control the size of nano-particles, making nano-films and blocks. Great progress has been made in the characterization of nano-materials, the formation and elimination of aggregates, surface adsorption and desorption, and the preparation of nano-composite particles and powders. Nano-ceramics with high density, complex shape and superior performance have been successfully developed. It is the first time in the world that nano-alumina grains appear superplastic deformation in the stress concentration area during tensile fatigue. Innovative achievements have been made in giant magnetoresistance effect, magneto-optical effect and spin wave vibration of granular films; It is the first time in the world that the magnetic transition of nano-perovskite particles exceeds that of metal GD. A new nano-composite oxide system was designed and prepared, and its absorption rate in mid-infrared band can reach 92%, which has been applied to infrared thermal fibers. A new method for preparing nano-alloy by amorphous complete crystallization was developed. Abnormal hall-petch effect was found in completely dense nano-alloys. In recent years, China has made great achievements in the research of functional nanomaterials, which has attracted international attention. Firstly, the synthesis of large-area oriented carbon nanotube arrays: the technology of efficiently preparing pure carbon nanotubes by chemical vapor deposition. The pore size of the nanotubes synthesized by this technology is basically the same, about 20 μm, the length is about 100 μm, the nanotube array area reaches 3 mm 3 mm, and its directional arrangement is high, and the spacing of carbon nanotubes is100μ m. This large area oriented carbon nanotube array has an important application prospect in the field emission cathode of flat panel display. This article was published in the American journal Science (65438-0996). The second is the preparation of ultra-long carbon nanotubes: for the first time, ultra-long aligned carbon nanotube arrays with a length of 2 ~ 3 mm were prepared in large quantities. This super-long carbon nanotube is 1 ~ 2 orders of magnitude longer than the existing carbon nanotube. This achievement has been published in the British journal Nature in August, 1998. The Financial Times introduced the work on long nanotubes with the title "Carbon nanotubes enter a long stage". Thirdly, the preparation of nitride nanorods: using carbon nanotubes as templates, one-dimensional nanorods with a diameter of 3 ~ 40 μm and a length of micron order were successfully prepared, and the concept of carbon nanotubes limiting reaction was put forward. This achievement was rated as one of the top ten science and technology news in China by 1998. Fourthly, the successful development of carbon nanotube array on silicon substrate promotes the application of carbon nanotubes in field emission plane and nano-devices. Fifthly, one-dimensional rice wires and cables were successfully prepared. After this research paper was read out at the 4th International Nano Conference held in Sweden from 65438 to 0998, many foreign scientists spoke highly of it. Sixthly, nano-nitrided microcrystals were prepared by benzene thermal method; Non-aqueous solvothermal synthesis technology was discovered, and zinc nitride microcrystals with particle size of 30 μm were prepared at about 300℃ for the first time. Chromium nitride (crn), cobalt phosphide (cop) and antimony sulfide (sbs) nanocrystals were also synthesized from benzene, and the paper was published in Science magazine 1997. Seventh, the nano-diamond is prepared by catalytic pyrolysis; Nano-diamond powder was prepared by catalytic pyrolysis of carbon tetrachloride and sodium in autoclave at medium temperature (70℃). The paper was published in the journal Science at 1998. The American magazine Chemistry and Engineering News also published an article entitled "Straw turns into gold-diamond made of carbon tetrachloride (cc 14)", which was highly praised. China's research on nanomaterials and nanostructures is accumulated on the basis of 65,438+00 years' work. On the basis of the Eighth Five-Year Plan, several nano-material research bases were initially formed. Shanghai Institute of Silicate, Nanjing University, Institute of Solid State Physics, Institute of Metal, Institute of Physics of China University of Science and Technology, Tsinghua University and Institute of Chemistry of Chinese Academy of Sciences constitute important units of basic research on nanomaterials and nanostructures in China. No matter from the perspective and foundation of the research object, or the academic level and applicability of the results, it has made contributions to winning a place in the international arena for China's nano-material research, promoting the development of China's nano-material research and cultivating high-level nano-material research talents. It also plays an important role in connecting basic research and applied research of nano-materials and accelerating the transformation of achievements. At present and in the future, these units are still the backbone of nano-materials and nano-structures research in China. In the past 65,438+00 years, China has established a variety of physical and chemical methods for preparing nano-materials, developed more than 65,438+00 devices for preparing nano-materials, including gas evaporation, magnetron sputtering, laser-induced cvd and plasma-heated gas phase synthesis, and developed chemical precipitation, sol-gel method, microemulsion hydrothermal method, non-aqueous solvent synthesis method and supercritical liquid phase synthesis method. In recent years, according to the development trend of international nano-materials research, many methods for preparing nanostructures (such as nano-ordered array system, mesoporous assembly system, MCM-4 1, etc.) have been developed. Especially self-assembly and molecular self-assembly, template synthesis, carbothermal reduction, droplet epitaxial growth, mesoporous ingrowth and so on. And successfully prepared a variety of quasi-one-dimensional nano-materials and nano-assembly systems. These methods lay a good foundation for further studying the physical properties of nanostructures and quasi-nanomaterials and promoting their application in nanostructured devices. The evaluation methods of nanomaterials and nanostructures are basically complete, reaching the international advanced level at the end of 1990s. To sum up, during the Eighth Five-Year Plan period, China made a number of innovative achievements in nano-materials research, formed a high-level scientific research team, occupied a place in the international arena for basic research, and a new situation appeared in applied development research, which laid the foundation for the sustainable development of nano-materials research in China. In the past 10 years, scientists and technicians in China have published more than 2,400 papers on nanomaterials and nanostructures in academic journals at home and abroad, ranking fifth in the world. Among them, carbon nanotubes and nanoclusters reported in a research report of the Institute of Solids of Max Planck Institute in Germany at the 1998 European Conference on Literature and Information Exchange that China's scientific and technological personnel published more papers than Germany, ranking third in the world, and held many international conferences on nanomaterials and nanostructures. So far, nano-materials research has won 1 National Natural Science Award and 2 National Invention Awards. There are 3 first and second prizes of natural science at the academy and ministerial level, 3 first prizes of invention, and special prize of scientific and technological progress 1 item; 79 patents were applied, of which 50% were invention patents, 6 were officially authorized invention patents, and 6 were achievements-transformed invention patents. In recent years, China nanotechnology workers have published some influential academic papers internationally, which have attracted the attention and praise of international counterparts. Six papers on the preparation of nanomaterials and nanostructures and nearly 20 academic papers (Phys. Rev Lite, J. Ain) have been published in Nature and Science. Chemistry. SOC。 ) The influence factor is above 6, and the influence factor of 365,438+0 is above 3. Articles included in sci and ei account for 59% of the total published papers. 1At the 4th International Conference on Nanomaterials held in Stockholm, Sweden in June, 1998, China's research on nanomaterials was highly praised, pointing out that China has made exciting achievements in the preparation of nanomaterials in recent years. In the summary of the conference, eight countries with good research methods on nanomaterials were selected to speak at the closing ceremony, and China spoke at the conference after the United States, Japan, Germany and Sweden.

4 Nanometer Industry Development Trend

(1) Nanotechnology in the information industry: The information industry not only plays an important role abroad, but also in China. In 2000, China's information industry created a GDP of 580 billion yuan. The application of nanotechnology in information industry is mainly manifested in three aspects: ① network communication, broadband network communication, nano-structured devices, chip technology and high-definition digital display technology. Because both communication, integration and display devices need original devices, the United States has begun to develop them. Now there are single electronic devices, tunneling electronic devices and spin electronic devices, which have been successfully developed in the laboratory and may enter the market in 200 1 year. ② Optoelectronic devices, molecular electronic devices and giant magnetoelectronic devices are still backward in China, but it will take 10 years for these original devices to enter the market. Therefore, China should study these aspects 65,438+05 to 20 years in advance. ③ Research level of key nano-devices in network communication, such as lasers, filters, resonators, micro-capacitors, microelectrodes, etc. It is not backward in China, but also exists in Anhui Province. (4) rheostat, nonlinear resistance, etc. It can be modified by adding zinc oxide nano-materials.

(2) Nanotechnology in environmental industry: Nanotechnology is an irreplaceable technology to degrade 20 nm pollutants in air and 200 nm pollutants in water. To purify the environment, nanotechnology must be used. Now we have successfully prepared a device that can degrade formaldehyde, nitrogen oxides and carbon monoxide, which can reduce harmful gases in the air from 10ppm to 0. 1ppm, and the device has entered the actual production stage. Photocatalytic nano-materials combined with porous beads have been successfully used to degrade organic substances in sewage, and also have a good degradation effect on other organic pollutants such as phenol that are difficult to degrade by traditional technology. In recent years, many companies are committed to transplanting nanotechnology such as photocatalysis into water treatment industry to improve water quality, and have achieved initial results; Nano-combination technology of rare earth cerium oxide and precious metal is also very effective in the transformation of automobile exhaust treatment device. Recently, the preliminary research on controlling algae pollution in freshwater lakes has been successful in the laboratory.

(3) Nanotechnology in energy and environmental protection: Rational utilization of traditional energy and development of new energy are important tasks for China at present and in the future. In the rational utilization of traditional energy sources, there are mainly cleaning agents and combustion improvers, which can make coal burn fully and circulate itself during combustion, reducing sulfur emissions without any auxiliary devices. In addition, there are additives that use nanotechnology to improve gasoline and diesel. In fact, it is a kind of liquid small molecule combustible cluster substance, which has the functions of combustion-supporting and purification. Foreign countries have made rapid progress in developing new energy sources, that is, changing non-combustible gas into combustible gas. At present, energy conversion materials are mainly developed in the world, and China is also doing it, including the conversion of solar energy into electrical energy, thermal energy into electrical energy and chemical energy into electrical energy.

(4) Nano-biomedicine: This is the most potential field after China's entry into WTO. At present, the international pharmaceutical industry is facing a new decision, that is, to develop the pharmaceutical industry on the nanometer scale. Nano-biomedicine is to extract necessary substances from animals and plants, and then combine them on the nano-scale to maximize the curative effect, which is precisely the idea of traditional Chinese medicine. After extracting the essence, a few skeletons, such as sugar and starch, which can be absorbed by human body, are used to release it efficiently and target drugs. Using nanotechnology can improve the performance of traditional drugs.

(5) Nano-new materials: Although nano-new materials are not final products, they are very important. According to American calculations, by the 265438+1930s, 40% of steel and metal materials in automobiles will be replaced by light and high-strength materials, which can save 40% of gasoline and reduce 40% of co2 emissions. This alone will create 1000 billion US dollars in social benefits for the United States of America every year. In addition, there are various functional materials. Glass is transparent, but heavy. Nano-particles are used to improve it and make it lighter, so that this material not only has mechanical properties, but also has other functions, such as changing color and storing light, reflecting various ultraviolet rays and infrared rays, absorbing and storing light, etc.

(6) Transformation of traditional industries by nanotechnology: For China, it is the best opportunity for nanotechnology to cut into traditional industries and combine nanotechnology with technologies in various fields. The first is the household appliances, light industry and electronics industries. Hefei Meiling Group began to develop nano refrigerators from 1996. The folding pvc magnetic refrigerator door seal is not moldy and adopts antibacterial coating. The fruit bowl inside is made of nano-materials. The development of light industry, electronics and household appliances can promote the development of coatings, materials and electronic components. Followed by textiles. Man-made fiber is the development trend of chemical fiber and textile industry. If China textile wants to occupy a favorable position after China's entry into WTO, it must now apply nanotechnology and nanomaterials in all directions. Last year, the application of nanotechnology was mentioned in the TV propaganda about thermal insulation quilt and thermal insulation clothing. Nanotechnology has special functions such as antistatic and flame retardant. When nano-conductive materials are assembled into it, the human body can be shielded under the high voltage of1.654,38+0.000 volts. In this respect, nanotechnology has a broad application prospect in textile industry. The third is the power industry. Using nanotechnology to transform 200,000-volt and 1 10000-volt variable voltage transmission porcelain bottles can improve the electric shock resistance of 1 10000-volt porcelain bottles in all directions, with no frosting on the glaze and excellent other comprehensive properties. Fourthly, coatings and coatings in building materials industry, including various ceramic glazes and inks, can improve product performance with the intervention of nanotechnology.

1On August 20th, 1999, American Businessweek predicted and evaluated life science and biotechnology, nano science and nano technology, and obtaining energy from other planets, and pointed out that this was a new challenge and opportunity for mankind to enter the 2 1 century. Laurel, a Nobel Prize winner, once said: Countries that attached importance to micron in 1970s have all become developed countries now, and countries that attach importance to nanotechnology now are likely to become advanced countries in the next century. Challenges are severe and opportunities are rare. We must pay more attention to the research of nanotechnology, pay attention to the intersection of nanotechnology and other fields, speed up knowledge innovation and technological innovation, and lay a solid foundation for China's economic take-off in the 2 1 century.

Editor's note: The exciting nano-era has arrived, and people's lives will change dramatically immediately. However, we should also be soberly aware that there are not many truly mature nano-materials on the market at present. Academician Bai Chunli, an academician of the Chinese Academy of Sciences, believes that "the real nano era has not yet arrived, and we are welcoming the arrival of the nano era with confidence."

Bai Chunli said, "The development and application level of nano-devices is an important symbol of mankind entering the era of nano-technology." With the development of nanotechnology today, how far is it from the arrival of the nano age? Bai Chunli said, "There is still a lot of basic research in nano-research, and there are still a lot of theoretical problems to be studied on the nano-scale. The development level of nanotechnology is similar to that of computer technology in the 1950s. It will take 30 to 50 years for mankind to finally enter the nano age. In 50 years, nanotechnology may be as popular as computer technology today. "

For nanotechnology, the scientific attitude is to actively participate in and promote the healthy development of this cutting-edge technology in a down-to-earth manner, and not to be commercial speculation or make scientific speculation.