History of Conductive Polymers

Nanostructured Conductive Polymers Edited Ali Eftekhari 2010 Wiley Sons, Ltd 

In the midst of this research, MacDiarmid was traveling in Japan and visited the laboratory of Hideki Shirakawa who was studying the Ziegler-Natta-catalyzed polymerization of acetylene. Standard practice was to use a concentration of the organometallic catalyst at the milhmolar level. It is a eatalyst after all. These low concentrations led to the infamous insoluble, intractable, black precipitate, but Shirakawa had discovered that with concentrations closer to molar, he obtained a shiny metallic film coating the wall of the reaction vessel. MacDiarmid returned to Pennsylvania, where he and Heeger quickly arranged to invite Shirakawa for a sabbatical visit. 

When the Holy Grad of copper replacement receded over the horizon, the emphasis in the late 1980s and early 1990s shifted to the optical properties. Since there is typically a large oscillator strength in the HOMO-LUMO transition of imdoped conjugated polymers. 

The semiconductive properties of conjugated polymers are also exploited for application in thin-film organic field-effect transistors (OFETs). The earliest materials examined were polyacetylene [17], polythiophene [18], and an oligomer of thiophene [19]. In these 

There is an additional constraint on the nature of the mixing, namely that the holetransporting p-type phase be continuous to the cathode, while the electron-transporting n-type phase connect to the anode. Controlling the morphology of such bi-continuous networks is the goal of recent research on self-assembled block copolymers. 

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The first and most important event in the history of conducting polymers occurred in 1978 when it was announced that the electrical properties of polyacetylene could be dramatically changed by chemical treatment (Chiang et al, 1978). 

We could compile the stories of polypyirole and other conducting polymers in a similar way, but the polyaniline saga alone provides an excellent illustration of the development of science. In fact, the discovery in the 1970s of polyacetylene— which had no practical importance but helped to arouse the interest of researchers and public alike— was another episode in the history of conducting polymers. Thus, these materials have a long history and— perhaps without any exaggeration—a bright future. 

As the brief history of conducting polymers tells, initially physicists played the dominant role in research of these materials. Naturally, they borrowed names for the species and phenomena from the nomenclature of their own field, as we have already seen in the case of doping. The terms polaron, bipolaron, and sometimes soliton are frequently seen in the literature on conducting polymers. These terms have been borrowed from solid-state physics. By polaron (Fig. 2a) in connection with CPs we mean radical ion introduced by oxidizing or reducing a conducting polymer molecule. The simple molecular orbital theory shows that the charge of a... 

Brief History of Conductive Polymer and Their Composites... 

A lot of fragments of the conducting polymers scientific history can be found in the chemical literature or in Internet articles. There are several specialized chapters in monographs, and also remarks in publications, dealing with early investigations in the special field of the respective paper, including a more or less adequate number of citations. Also anecdotes, dealing with the influence of the human factor in the history of conductive polymers can be found, particularly on the Internet. 

Last but not least, the historical development of conductive polymers from laboratory curiosities of unknown structures to small-scale chemicals of paramount scientific importance to multiton commercial technical products will be presented. Only a few publications until now have dealt with the science history of conductive polymers, and often only parts of the story have been told. The viewpoint of an industrial research group with the backgroimd of more than 25 years of continuous conductive polymer research will be incorporated into the historical description, it is hoped, without expanding this part of the book and ending at the time when PEDOT was commercialized. 

One early program carried out at AUied-Signal, Inc. proposed the use of conductive polymers in remotely readable indicators (210). Conductivity changes induced in the conductive polymer could be read externally and the history of the sample known. Systems designed to detect time—temperature, temperature limit, radiation dosage, mechanical abuse, and chemical exposure were developed. 

Polymer mixtures have attracted some historical interest,320 as have liquid crystalline polymers.321 Several papers have examined the history of conducting polymers322 and of organic superconductors,323,324 the first having been discovered by Jerome in 1980. 

Armand (1994) has briefly summarised the history of polymer electrolytes. A more extensive account can be found in Gray (1991). Wakihara and Yamamoto (1998) describe the development of lithium ion batteries. Sahimi (1994) discusses applications of percolation theory. Early work on conductive composites has been covered by Norman (1970). Subsequent edited volumes by Sichel (1982) and Bhattacharya (1986) deal with carbon- and metal-filled materials respectively. Donnet et al. (1993) cover the science and technology of carbon blacks including their use in composites. GuF (1996) presents a detailed account of conductive polymer composites up to the mid-1990s. Borsenberger and Weiss (1998) discuss semiconductive polymers with non-conjugated backbones in the context of xerography. Bassler (1983) reviews transport in these materials. 

A concise report describing the history and scope of the studies in the area of conducting polymers can be found in Kanatzidis, M. G. Chem. Eng. News, 1990, 68, 49, 36. 

A Brief Overview and History of the Development of Conductive Polymers... 

A review of the history of the development of silicon MEMS shows that production of single devices for mass markets has been the dominant pattern in commercialization. The first products were pressure sensors for the automobile mass market. Next came the accelerometers for the same market, and more recently optical switches and ink-jet printheads. Similar parallels can be seen in the development of conducting polymer devices. Of the wide variety of prototype sensors, actuators, and electrical components that have been demonstrated over the past 10-15 years, only polymer LEDs have been completely commercialized. Smart systems utilizing MEMS and conjugated polymers, which were anticipated to be the killer app, have yet to make their appearance. 

A brief history of research on conducting polymers, with specific emphasis on results in the area of conducting polymers as corrosion-protective coatings is presented. The synthesis and corrosion inhibiting properties of poly(bis(dialkylamino)phenylene vinylenes at isotonic sea water conditions are presented and discussed. 

Polyacetylene remains the archetype of this second class of materials. However, despite a high conductivity, its instability in atmospheric conditions constitutes a major obstacle to practical applications. A milestone in the young history of conjugated polymers is the synthesis of more stable heterocycle-based polymers such as polypyrrole [3] and polythiophene (PT) [4,5] in the early 1980s, together with the discovery that these polymers can be easily obtained in their oxidized conducting form by means of a one-pot single-step electrochemical synthesis. 

What is a polymer This was a controversial question just before synthetic polymers were prepared for the first time, not to speak of "conducting polymers." The character of macromolecules was the topic of fimdamental discussions in the first half of the 20th century—one of the most fascinating scientific debates in the history of chemistry. After Hermann Staudinger s concept of covalent bonds between the building blocks of macromolecules was accepted by the scientific community, the tremendous scientific and industrial development of synthetic polymers got a new and even more expansive dimension. 

Photovoltaic (PV) cells, 23 32-53. See also Photovoltaic materials commercial history of, 23 49—51 conducting polymer applications, 7 541 polymethine dyes in, 20 516—517 selenium, 22 100, 103 spectrum and band gap of, 23 37-39 structure of, 22 220-221 third generation, 23 44 workings of, 23 32-37 Photovoltaic detectors, 19 133, 138 Photovoltaic detectors/arrays/focal planes, 19 163-164... 

A very important electrochemical phenomenon, which is not well understood, is the so-called memory effect. This means that the charging/discharging response of a conducting polymer film depends on the history of previous electrochemical events. Thus, the first voltammetric cycle obtained after the electroactive film has been held in its neutral state differs markedly in shape and peak position from subsequent ones [126]. Obviously, the waiting time in the neutral state of the system is the main factor determining the extent of a relaxation process. During this waiting time, which extends over several decades of time (1-10 s), the polymer slowly relaxes into an equilibrium state. (Fig. 13) After relaxation, the first oxidation wave of the polymer appears at more... 

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