Application Prospects of Conductive Polymers

Research field.

1 In the common concept, metal is a good conductor of electricity, and plastic is non-conductive and is often used as an insulating material. However, the 2000 Nobel Prize in Chemistry has changed this traditional concept. Polymers such as plastics can be made conductive like metals, and they can be made into new materials with various special properties. In fact, there were reports in this area 20 years ago. The Japanese chemist Jieki Shirakawa and others called it an organic polymer for electrical transmission. 1313,4,1, said coffee 17,8, now scientists claim that It is a conductive polymer conductive molecule, 0 is also Xiao, 618 or synthetic metal 87 plus 6068. Now this new discovery has many important applications, and has attracted close attention of chemist physicist materialist electronics biologists , It is expected that like FUllerene chemical samples, with the advancement of extensive practical application, many new technologies, new materials and new industrial groups will be produced, and the future chemical industry will be greatly influenced and many new challenges will be raised.

2 conductive polymer and conductive mechanism From the perspective of structural chemistry to understand, the so-called polymer is the molecular structure of the long-chain polymers continue to repeat. Plastic is a type of wire insulation that is typically not used to conduct current. In addition to this, like rubber fibers are also polymers, their structure is the same as plastics, and all chemical bonds are saturated, so they can not conduct electricity, and they are used as tire cloths or daily necessities. Because these materials are mostly plastic or elastic, they are all flexible polymer materials. Since 1860, Parks, such as the first exhibition of artificial plastics at the London International Exposition in the United Kingdom, has overrepeated the plasticity of plastic for over 100 years, ignoring the development of other properties.

In terms of classification, polymers can be classified into inorganic polymers and organic polymers. After 1973, Mark Dermity, professor of chemistry at the University of Pennsylvania, Philadelphia, USA, 18 melons 18; 1 directly engaged in inorganic polymer sulfur nitride 81 film research. Prior to this, in 1971, Bai Yingshu, who was far away in Japan, conducted research on organic polymer polyacetylene 01. Although the subjects of the two studies are different, their interests are like making polymers into electrical conductors.

From the analysis of the conductive mechanism, when polyacetylene becomes a conductor, it must imitate the metal, that is, the electrons of the polymer must be able to move freely instead of being bound to the atom. In other words, the first condition for the polymer to become metallic is that the polymer must have a conjugated double bond, that is, the polymer molecule is composed of alternating single and double bonds; secondly, to increase the conductivity, the author must be briefed on Zhang Wengen. Born in 1959 in 1982, Associate Professor of Shaanxi Normal University graduated in the direction of the history of chemistry and methodological methods to remove some of the electrons similar to the hole or add part of the electrons, which can be done by redox doping.

To polyacetylene, to make it meet the first condition of conduction, it must be made into a kind of flat molecule. At this time, the bond atoms are 52 hybrids, the bond angle is 120 degrees, and the other, 2 tracks can be The conjugated molecules are formed side by side, so this polymer should have two different isomers, cis and trans. Bai Yingshu discovered that a new method can be used to synthesize polyacetylene, and the ratio of the cis and trans structures can be controlled on the black polyacetylene film that appears on the top of the reactor. Things are caused by accidental experiments.

Bai Yingshu is directly engaged in organic semiconductor research at the Institute of Resources Science at Tokyo Institute of Technology. He often uses polyacetylene black powder, and its synthesis can be achieved with Ziegler Natta, an eglerNatta desensitizer. The secondary research institute added a catalyst thousand times higher than the normal concentration to the reactor. As a result, the synthesized polyacetylene was not a powder in the usual case, but formed a silver film. It was this mistake that should not have occurred that inspired Bai Yingshu. The metal luster film could conduct electricity. They reacted at different temperatures and the result was a copper-colored film. The former was trans-polyacetylene, and the latter was cis-block. Later, they used acetylene as a raw material, and under the action of 4 people off 3 catalysts, successfully synthesized and separated these two kinds of plastic films with high elasticity, and measured their electrical conductivity. Bodybuilding.

In 1976, when Mark Dermity learned of Bai Yingshu's discovery, he invited Bai to go to the United States for joint research. They exposed the polyacetylene film to 133.31 iodine vapor or bromine vapor at room temperature for oxidation modification 10, inorganic semiconductor doping. It is clear to Bai Yingshu that the optical properties of polyacetylenes will change during the oxidation process, and Mark Dermid suggested that the physicist Hager 1 priest 7186 of the University of California, Santa Barbara, be taught to measure the electrical conductivity. As a result, polyacetylene silver films doped with iodine atoms or bromine atoms increased the conductivity of trans-polyacetylene by tens of thousands of times, reaching a value of 0.5, 1.1977 years. They jointly published the paper and disclosed the great discovery. In the same year, Bai Yingshu demonstrated the experimental fact that plastics can conduct electricity at the International Academic Conference of the New York Academy of Sciences.

Following polyacetylene, scientists have discovered and prepared many conductive polymers by studying other conjugated system polymers. Among them, poly-p-phenylpyrrole polyaniline poly(p-phenylenediylene) and other conductive materials can reach 1 order of magnitude. Chemical stability is superior to polyacetylene. Since then, the development in this area has grown by leaps and bounds, and many exciting new applications have emerged.

3 In terms of miraculous efficacy and wide applications, objects can be classified into insulator semiconductor conductors and superconductor species. The former has a conductivity coefficient ranging from small molecules to changes from insulators to semiconductors to conductors. This is currently possible in all substances. This morphological change spans a great deal of excellent application performance, opening a new page for the wide application of polymers such as plastics.

Electronic Devices After 1977, Haig invented an ultra-thin, bendable electronic device light-emitting diode using a conductive polymer, and took the first step in the practical application of conductive polymers. Now, the performance of light-emitting diodes has been developed to be comparable to that of inorganic luminescent materials. The polyacyl polypyrrole polythiophene tubes that have appeared one after another have been commercialized. In 1986, Japan used polythiophene as the field effect. tube. This will be an important breakthrough in the future application of conductive polymers.

Electromagnetic shielding materials Traditional electromagnetic shielding materials are mostly copper, and conductive polymers have anti-static properties, so it can also be used for electromagnetic shielding, and its low cost, no consumption of resources, can be easily used in any area, so high conductivity Molecules are ideal substitutes for electromagnetic shielding materials. They can be used in computer room mobile TV computers and heart pacemakers. Using this feature, people have developed computer screensavers that protect users from electromagnetic radiation. In this regard, polyaniline is considered to be the most promising new material for electromagnetic interference shielding and an ideal material for the manufacture of gas molecular films.

Batteries and Conductive Materials Conductive polymers have the properties of doping and dedoping and can therefore be used as charge and discharge batteries and electrode materials. Japan Bell spinning company has successfully developed polyacetylene plastic batteries, which are light and popular with consumers. In this regard, polypyrrole has a great advantage, it has a higher degree of doping and greater stability, is also very sensitive to changes in electrical information, if you apply the polypyrrole in traditional textiles can make It becomes an electrical conductor, so soluble polypyrrole can be used as a sensitive chemical sensor for monitoring low concentrations of volatile organic compounds; in addition, a polypyrrole capacitor and a flexible liquid crystal light valve have been developed by utilizing its characteristics, and a polypyrrole capacitor industry has also been developed. Has achieved commercialization.

Super-large TV screens are similar to polymers such as plastics, and the conductive polymers are still plastic. Using this feature can provide humans with some amazing screens and form a complete image that needs to be composed of tens of thousands of elements. If one of them is wrong, it will cause the entire Like distortion, this makes the product defective and expensive. The display screen of conductive polymer makes it easy to solve this problem, especially for ultra-large or curved display screens, and the influence of impurities is minimal.

In addition to other applications, changes in the shape of conductive polymers from insulators to semiconductors to conductors can make the cruise missile invisible during flight, and the insulation detonates after approaching the target; using its microwave absorption characteristics, can be made Into various uses of stealth coatings; the use of its anti-corrosion, can be used for rocket ship oil pipeline sewage pipe; use of its electrical properties can be made to glow wallpaper anti-static carpet smart windows, can adjust the room environment according to changes in external conditions, so that The environment in which people live is more comfortable; in addition, conductive polymers can be used in the manufacture of solar cell anti-static photographic film human computer light traffic signs.

Conductive polymers not only have great application value in the fields of scientific experimentation and daily life in the national security national economy industry, but also the huge potential business opportunities that have given birth to many entrepreneurs have focused their attention on the development and application of conductive tube molecular products. . U.S. International Business Machines Corporation, Ministries of Japan and Asahi Kasei Torayi Teijin have begun the process of obtaining new U.S. patents for polymer conductive materials. In 1998, the NesteOyj head office was re-exported, 1 Limited Company, aiming at the application of conducting polymers. The company not only owns a pilot chemical plant for the production of polyaniline components, but also an industrial compounding plant with mixed components. The series of products developed can be used together with other components such as Polypropylene Polypropylene Polystyrene 7, Epoxy Thermoplastic Elastomer, etc. in addition to being used as a single component. Its application range involves construction of antistatic packaging materials. Printed circuit boards made of antistatic flooring materials Textiles Conductive textiles Automotive paints for facades Blasting ducts for the mining industry Intelligent windows for building and automotive industries.

Intelligence Survey 4 Faced with Question and Future Prospects 4.1 Q Although conductive polymers have prepared a beautiful future for the world, there are still many questions in the development process. This new field had not been well solved due to the large-scale application, and the research level of conductive polymers fell into a trough. However, the Nobel Prize in Chemistry in 2000 affirmed the preliminary basic research and theoretical explanations, and also demonstrated the conductivity. The development of polymers is still a research hotspot in the fields of materials and high-tech, and many research results in the near future will predominate in the field of materials in the 21st century.

Although opportunities and challenges coexist today, conductive polymers are far away. The conductive polymer is still not perfect theoretically. Basically, the concept of inorganic semiconductors and doping are still used, and the metal state is not fully achieved. It is necessary to re-establish the synthetic metal approach from the perspective of molecular design. As far as the conductive mechanism is concerned, conductive plastics are doped with semiconductor materials in plastics. The process is a simple composite process. The formation of conductive polymers is a molecular synthesis process and is intrinsically conductive. Therefore, conductive polymers cannot be called conductive plastics. There are essential differences between these two concepts.

In the 1980s, polyacetylene's conductivity coefficient was in the order of 103. After 1986, the highly oriented poly-blocks increased the conductivity by orders of magnitude. After 1988, the scientists brought polyacetylene's conductivity to 105 orders of magnitude, close to that of copper and silver. Conduction at room temperature. Organic polymers can achieve high levels of conductivity, and how they can achieve higher levels, which involves a series of theoretical and technical questions, all require careful research.

At the molecular level, there are still many questions on the self-assembly of self-assembled molecular devices for conductive polymers. At the forefront of conducting polymer life science research, the latest research found that DNA is also conductive, can be combined with conductive polymers and DNA, the use of conductive polymers to create artificial muscles and artificial nerves to promote DNA growth and modification of DNA Although it is predictable that this will be the most important trend in the application of conductive polymer research, the relationship between all human perceptions, including the olfactory sense of skin and muscles, and electrical signals is not yet clear, and further research is needed. .

4.2 Looking at the combination of conductive polymers and nanotechnology, molecular lead molecular circuits, molecular devices and other electronic components can be made, which will promote the development of the world-class industry and open up a broader perspective for thin and lightweight batteries and microdisplays. In the future, high molecular polymer batteries can also be used in electric vehicles to make cars truly zero-pollution; polymer wires can penetrate into every family; and polymer chip heads will surely become the main force in the 21st century material revolution. However, there is still considerable distance between monomolecular and single-molecule electronic devices. If this day can become a reality, it will surely cause a revolution in electronic technology.

It has been found that many conductive polymers have unusual order nonlinear optical properties, and polymers having a polydiacetylene backbone have been proven to have ferromagnetism. In this way, how to study the photoelectromagnetic behavior of high molecular polymers at the molecular level to discuss the relationship between molecular structure and light electromagnetic properties will inevitably lead to the emergence of new generations of functional materials, which will cause major changes in the photonics industry and information science and technology. breakthrough.

In practical applications, conductive polymers are still in breakthrough research and verification. Its performance price, market demand and other aspects can not compete with inorganic materials; its stability also needs to be strengthened; its dedoping 10 has not yet been well resolved; its processing performance and mechanical properties are also worse than engineering plastics. These difficult questions need to be well studied and solved before the application of conductive polymers on a large scale.

5 Conclusion China's research in the field of conductive polymers started in 1978, has been more than 20 years of history, and its research has been in line with international standards. Academician Qian Renyuan from the Institute of Chemistry, Chinese Academy of Sciences, has been conducting research on conducting polymers since the late 1980s and has made outstanding achievements in the research of conducting polypyrrole. Another researcher at the Institute of Chemistry of the Chinese Academy of Sciences Wan Meixiang has studied with Professor Mark Demidity and has been directly involved in the research of the structure and properties of conductive polymers. He has made unique achievements in the magnetic properties of conductive polymers, and he has made nano-tubes that can conduct electricity. . However, compared with Japan and the United States, China's human and material resources in the field of conductive polymers are still far from enough.

We often say that we should use our talents and make the best use of them. For conductive polymers, we do not necessarily require its electrical properties to be completely copper-like, as long as we can use its features to play its role in some special occasions. Therefore, before the conductive polymer is incompletely metallic, as long as it can be positive in terms of light plasticity and high elastic flexibility, especially in conductive doping and dedoping antistatic properties, electrical information sensitivity, microwave absorption, and the like, etc. Development and research, it is not difficult to find a place for conductive polymers.

From this point of view, coupled with the metallization bio-intelligentization of conductive polymers and the molecularization of conductors and components in the future, it is not difficult to imagine the application of materials related to electricity in fields such as chemical physics, electronics and biology, and in daily life. How conductive polymers change our world!

Guo Lin. American and Japanese scientists won the Nobel Prize in chemistry. The Bright Times reported the Nobel Prize for chemistry. China Business News, 10,82000 Xinhua News Agency. US and Japan scientists won the Nobel Prize in chemistry. The sheep’s field is late in the morning. The 2-year Nobel Prize in Chemistry was announced. Science and Technology 0, 12 2000 Nobel Prize winners and their achievements. Middle school chemistry teaching reference Wu Zhongguo. Nobel Prize Winner Yingying Bai. Technology News, Xu Dexin. Conductive polymer goes to the front desk. Scientific Times, 10,1732000 Li Hong, Bi Chongguang. A century-long review of the Nobel Prize in Natural Science. New Horizons Zhang Lian, Zhang Hua. Nobel Prize in Natural Science Award for the Centennial Review of Chemistry. New Zhang Wengen. 16 Yang! Chemistry and Future Chemical Industry. Shanghai Chemical Industry.

Wang Danhong. How plastics become electrical conductors. Scientific Times, 17 Received March 2001