Conductive polymers or, more precisely, intrinsically conducting polymers icps are organic. Conducting polymers, fundamentals and applications. The name refers to its conceptual construction from polymerization of acetylene to give a chain with repeating olefin groups. As its name implies, this polymer molecule is built from smaller molecules of acetylene, the substance that burns in welders torches.
Polyphenylenes and other conductive polymers properties. To explain the conduction mechanism in conducting polymers, a new model called soliton model was intro duced by a. As synthesized conductive polymers exhibit very low conductivities. Pdf conducting polymers and their applications researchgate. Polyacetylene polymer an overview sciencedirect topics. Introduction polymers plastic shape our lives because polymers can be shaped. In general a half filled valence band, formed from a continuous delocalized. Enhanced stability of conductive polyacetylene in ladderlike surface. Comparative photos of printed samples of commercial pedot ink. When silvery films of the semiconducting polymer, transpolyacetylene, ch x, are exposed to chlorine, bromine, or iodine vapour, uptake of halogen occurs, and the conductivity increases markedly over seven orders of magnitude in the case of iodine to give, depending on the extent of halogenation, silvery or silveryblack films, some of which have a remarkably high conductivity at room.
Effect on conductivity of polyacetylene and polyaniline after doping. However, there are at least four major classes of semiconducting polymers that have been developed so far. Polyaniline is one of the most important conducting polymers, along with polypyr role and poly3,4ethylenedioxythiophene. This book deals with the practical fundamentals and applications of conducting polymers. We shall highlight some specific examples of such systems and discuss some of their potential applications. The synthesis and p and ndoping of polyacetylene, chx, the prototype conducting polymer or synthetic metal is described together with a qualitative description of its band structure and changes in band structure on doping to yield posive and negative solitons. Ch x are exposed to chlorine, bromine, or iodine vapor, uptake of halogen occurs. The metathesis polymerization of 7,8bistrifluoromethyltricyclo4. New for conducting polymers solitons, polarons, bipolarons. A study of the electrical conductivity of the halogen doped transpolyacetylene system, ch x, is reported. Polypphenylene vinylene ppv and its soluble derivatives have emerged as the prototypical electroluminescent semiconducting polymers.
The chemistry nobel prize in 2000 was awarded for the. Today, poly3alkylthiophenes are the archetypical materials for solar cells and transistors. The first observation of the shiny lustrous polyacetylene film the search for conducting polymers, incidentally, goes back to the days of natta of the zieglernatta. Conductive organic polymers associated with a protic solvent may also be selfdoped. The concepts discussed in this chapter are referred to throughout the other chapters, and should be a good primer for newcomers to this field as well as a reference to the literature for others. These are polymers with alternating single and double carboncarbon bonds in their chains. Metalinsulator transition in organic systems, department of physics, hebrew university, jerusalem, israel, 20 october 1972. First, we explain its structure by means of the tight binding approximation and the peierls distortion. Lecture on intrinsically conducting polymers on textiles en. Since the discovery of the first conducting polymer, polyacetylene in 1977. Conductive polymerbased membranes, conducting polymers in sensor design, conducting polymer aerogels, coating of conducting polymers on natural cellulosic fibers, electrical properties of polymer lightemitting devices, exfoliated nanocomposites based on polyaniline and tungsten disulfide, phenylenevinylene systems. Conducting polymer research dates b ack to the 1960s, wh en pohl, katon, and their co workers, first synthesized and characterized semiconducti ng polymers 3.
Linearbackbone polymer blacks polyacetylene, polypyrrole, polyindole and polyaniline and their copolymers are the main class of conductive polymers. With the invention of conductive polyacetylene in the 1970s, conducting polymers have received significant attention from. Chapter 1 provides an introduction to the field of conductive polymers. In its linear form it precipitates as a black, air sensitive, infusible and intractable powder out of solution and can. The properties that make these conductors attractive include a wide range of electrical conductivity, which can be achieved by doping, while maintaining mechanical flexibility and high thermal stability. Other conducting polymers naturally, interest soon turned to other conjugated polymers such as polypphenylene, polypyrrole, polythiophene and polyaniline, and their. The electrical conductivity will be realised by doping these polymers. Maybe not, but it is the major driving force behind most research that tries to design plastics fit for electronic applications. Other conjugated polymers, such as polyaniline pani, poly3.
Design, synthesis, and control of conducting polymer. On the other hand, doping of polymer leads to the formation. Organic polymers are normally insulators, it can be presumed that conducting polymers must have an unusual structure. Synthesis and characterization of conducting polymer. Conducting polymers have garnered a great deal of attention since the discovery of metallic conductivity in polyacetylene in the 1970s by hideki shirakawa, alan heeger, and alan macdiarmid, a feat leading to their 2000 nobel prize in chemistry. Indeed, a number of theoretical studies have shown that coplanarity along the chain r orbitals leads to better electrical propertieskld and nonlinear optical properties. What links here related changes upload file special pages permanent link. Shirakawa, heeger and macdiarmids work on conducting polyacetylene led to a theoretical revolution, and the development of. Conducting onedimensional organic salts, industrial affiliates program in physical electronics, university of illinois, urbana, illinois, 18. Polyacetylene, structurally the simplest conjugated polymer, exhibits the highest conductivity among conjugated polymers but also very low stability. The behavior of the halogenated polyacetylene is like that of a series of. In 1976, alan macdiarmid, hideki shirakawa and alan heeger discovered the conditions to dope the icps over a full range from insulator to metal, in particular for polyacetylene nobel prize in chemistry in 2000. This compound is conceptually important, as the discovery of polyacetylene and its high conductivity upon doping helped to launch the field of organic. Conducting polymers encyclopedia of life support systems.
Typically conventional polymers such as plastics, rubbers, etc. Conductive polymers applications for electronic devices. The following 19 files are in this category, out of 19 total. Polyacetylene is type of conjugated polymer, could become highly electrically conductive after undergoing a structural modification process called doping. Polymer basics long chain like molecular structure where repeated molecular units are connected by covalent bonds polymers used as insulators eg.
Conducting polymers have received a lot of attention, with the invention of conductive polyacetylene. Polyaniline was first described in the mid19th century by henry letheby, who. They are oligomeric or polymeric materials composed of phenylene rings and related units such as naphthalene, anthracene or heteroaromatic rings such as pyrrole and thiophene, which are connected to one another through carboncarbon single bonds or. Suarezherrera encyclopedia of life support systems eolss happens inside the polymeric material and the insulating neutral polymer is converted into an ionic complex consisting of a polymeric cation chemical reaction 1, or anion. Conducting polymers intrinsically conducting polymers icps are. Conducting polymers are known to mechanically respond to electrochemical stimuli and. Conductive polymers have seen great advancement during the last two decades. However, a few intrinsically conducting polymers icps exist that have alternating single and double bonds along the polymer backbone conjugated bonds or that are composed of aromatic rings such as phenylene, naphthalene, anthracene, pyrrole, and thiophene which are connected to one another through carboncarbon single. Both luck and insight played roles in the discovery of the first conducting polymer, a form of the material called polyacetylene. Written from a pedagogical point of view and at a very basic level, it provides a thorough grounding in cps ideal for further work, as a reference, or as a supplementary course text. If you continue browsing the site, you agree to the use of cookies on this website. In contrast, typically doping in the polyacetylene derived conductive polymers involves actually oxidizing the compound. Pdf during the past two decades, both fundamental and applied research in.
This book is comprised of 12 chapters and begins with an introduction to a few basic principles of polymer chemistry and solidstate physics, followed by an overview of chargetransfer salts and conducting polymers other than polyacetylene and a historical background on polyacetylene and a general description of its properties. The perspective is that of a chemist who is also interested in the physics of conductive polymers. It is not until an electron is removed from the valence band pdoping or added to the conduction band ndoping, which is far less common does a conducting polymer become highly conductive. Synthesis of asymmetric starbranched polymers having two polyacetylene arms by means of living anionic polymerization using 1,1diphenylethylene derivatives. The effect of this oxidation or reduction on polymer is called doping, i.
Doping p or n generates charge carriers which move in an electric field. Unesco eolss sample chapters electrochemistry conducting polymers marco f. For example, metal cables are coated in plastic to insulate them. Melanin is the classic example of both types of doping, being both an oxidized polyacetylene and likewise commonly being hydrated.
Polyacetylene polythiophene polypyrrole polyaniline polypphenylenevinylene n nh n n h n s some conjugated polymers can be made conductive. Precursor routes to conducting polymers from the ring. Electronic polymers insulators semiconductors metals superconductors. Examples of intrinsically conducting polymers are polyacetylene, polyaniline and polypyrrole. Synthesis of electrically conducting organic polymers. Box 4 explains the use of the chemical approach to prepare conducting composites. Conducting organic polymers also show great promise in other areas, such as solar cell technology and the production of flexible integrated circuit boards. Intrinsically conducting polymers icps have been the subject of intense research.