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Metallic Properties of Conductive Polymers due to Dispersion
Abstract
A review is presented summarizing the (at that time) available basic knowledge about conductive polymers / organic metals, experimental and theoretical results - dispersion, self-organisation, rheology, non-equilibrium thermodynamics, practical applications.
... t variation in the experimental conditions during their preparation may cause different results [42 – 49] and many authors have reported approximate conductivity values. [42,43,50 – 55] For that reason, solid dispersions of intrinsically conductive polymer (ICP) in thermoplastic matrices are generally regarded as thermodynamically unstable systems. [56] Recently, a theory for heterogeneous polymer composites was proposed [56 – 67] on the basis of general non-equilibrium considerations of the chemical reactions, [68] fundamental background of conductive polymeric composites, and LMSC33680 LMSC_044_004 Techset Composition Ltd, Salisbury, U.K. [56,58,59,62 – 67] The main principles of thi ...
... s in the critical zone of instability; (iii) the dispersed or flocculated conductive polymer systems could serve as examples of chaotic (dissipative) structures; (iv) the instability phenomena and the dissipative structures in the conductive polymer composites have common features, namely negative dispersion entropy and positive free Gibbs' energy. [56,62,67] Many experimental observations and theoretical considerations [56 – 67] have revealed that the dispersion (blending) of submicron conductive particles leads to a specific dissipative structure, probably a highly ordered adsorbed monolayer in which, directed by the interfacial energy, a change of dispersion state from a completely ...
... 3 Typical dc conductivity is frequently a result of various electronic transport processes and is ca. 10 -10 2 S/cm for disoriented and oriented PANI-ES (see Fig. 1). 36,44,52,[60][61][62][63][64][65][66][67] For example, this value has been determined for PANI-CSA to vary in the range r dc % 1.0 Â 10 2 -3.5 Â 10 2 S/cm at room temperature. 66,68 The variety of conducting properties makes difficult to investigate completely and correctly by usual experimental methods true charge dynamics along a polymer chain, which can be masked by interchain, interglobular, and other charge transfer processes. ...
The main results of the study of charge transfer in polyaniline modified with sulfuric, hydrochloric, camphorsulfonic, 2-acrylamido-2- methyl-1-propanesulfonic and para-toluenesulfonic acids at various (9.7 - 140 GHz) wavebands EPR obtained in the Institute of Problems of Chemical Physics RAS are summarized. The methods of determining the composition of polarons with different mobility and their main magnetic, relaxation and dynamics parameters from effective EPR spectra are described. The dependences of the nature, electronic relaxation, dynamics of paramagnetic centers, and the charge transfer mechanism on the method of synthesis, the structure of the acid molecule, and the The main results of the study of charge transfer in polyaniline modified with sulfuric, hydrochloric, camphorsulfonic, 2-acrylamido-2- methyl-1-propanesulfonic and para-toluenesulfonic acids at various (9.7 - 140 GHz) wavebands EPR obtained in the Institute of Problems of Chemical Physics RAS are summarized. The methods of determining the composition of polarons with different mobility and their main magnetic, relaxation and dynamics parameters from effective EPR spectra are described. The dependences of the nature, electronic relaxation, dynamics of paramagnetic centers, and the charge transfer mechanism on the method of synthesis, the structure of the acid molecule, and the polyaniline oxidation level are shown.
... So we designed dispersion processes capable of overcoming these extreme surface forces (4). In solvents, we can disperse the conductive polyaniline (or other polymers) down to the primary particle size, ~10-15 nm (5). ...
Organic metals were a euphoric dream in the 1980s and a disappointment in the 1990s. Now they are moving to the marketplace.
This book introduces the principles of electrochemistry with a special emphasis on materials science. This book is clearly organized around the main topic areas comprising electrolytes, electrodes, development of the potential differences in combining electrolytes with electrodes, the electrochemical double layer, mass transport, and charge transfer, making the subject matter more accessible. In the second part, several important areas for materials science are described in more detail. These chapters bridge the gap between the introductory textbooks and the more specialized literature. They feature the electrodeposition of metals and alloys, electrochemistry of oxides and semiconductors, intrinsically conducting polymers, and aspects of nanotechnology with an emphasis on the codeposition of nanoparticles. This book provides a good introduction into electrochemistry for the graduate student. For the research student as well as for the advanced reader there is sufficient information on the basic problems in special chapters. The book is suitable for students and researchers in chemistry, physics, engineering, as well as materials science. - Introduction into electrochemistry - Metal and alloy electrodeposition - Oxides and semiconductors, corrosion - Intrinsically conducting polymers - Codeposition of nanoparticles, multilayers
The new corrosion protection technology with polyaniline, an Organic Metal (conductive polymer), is presented. It is based on an immense surface ennobling and the formation of a passivating metal oxide. The requirements for efficiently working coating systems, comprising the dispersed Organic Metal containing primer, eventually an intercoat, and a top coat, are characterized. An integrated 4-step-method ("scientific engineering") has been developed and is successfully used for the systematic development of such coating systems. The combination of the measurement of the open circuit potential, a new scratch test, EIS and SKP together are a powerful tool for predicting the results of accelerated corrosion tests and real-time corrosion prevention performance. Organic Metal coating systems are out-performing even the best conventional anti-corrosion coating systems.
Conducting polymers have been synthesized before by mixing polymers with metal or graphite powders. But in the case of a new class of materials, the conductivity was an intrinsic property. Therefore, the name intrinsically conducting polymers (ICPs) was recommended. Conducting properties can be achieved by reduction of the neutral state. An example is the poly(dibutoxyphenylenevinylene). A platinum electrode coated with polymer in acetonitrile showed the transition between neutral and oxidized state at +1V versus a platinum quasi-reference electrode and the transition between neutral and reduced state at –1.8V. The reduced state has received much less attention than the oxidized state. The oxidation process is reversible as it is possible to switch between the oxidized and neutral states. Otherwise, oxidation and reduction of conducting polymers are very complex processes. Therefore, the reversibility is limited and depends on the timescale. In a periodic oxidation–reduction cycle, only quasi-stable oxidized and reduced polymers can be expected. During synthesis or in the process of oxidation the chain of the conjugated polymer is positively charged. The charging can reach a degree of up to 25–30%. Anions are intercalated into the polymer structure to compensate the positive charges of the polymer chain. Conducting polymers can be synthesized by following conventional polymer synthesis routes. One can transfer the Ziegler-Natta synthesis of polyethylene to polyacetylene. The Ziegler–Natta catalyst is solved in large excess in an inert solvent with acetylene streaming over the surface. A black film of polyacetylene is formed on the liquid surface.
Polymers are generally insulators, and they have been increasingly used as substitutes for structural materials—such as metals, wood, and ceramics—because they can be produced from cheap raw material; are light in weight, low-temperature processible, and corrosion resistant; and demonstrate high mechanical strength. This chapter discusses the class of intrinsically conducting polymers where the chemical structure can produce, sustain, and assist the motion of charge carriers (electrons and holes) necessary for electrical conduction. For a polymer to be included in this class, it must possess a conjugated backbone, which provides a great degree of delocalization of π-electrons. The overlapping set of molecular orbitals gives reasonable carrier mobility along the polymer chain. The charge carriers must be provided extrinsically by a charge-transfer process, which is generally called “doping”; because pristine polymer contains no charge carriers, p-type and n-type doping of conjugated polymers is carried out by reaction with oxidants and reductants, respectively. To show electronic conduction, a polymeric system must possess both an orbital system, which allows charge carriers to be mobile, and the charge carriers. The various aspects of the stability of electrically conducting polymers (ECPs) are also discussed in the chapter.
The review summarizes the results of the study of emeraldine forms of polyaniline by multifrequency (9.7–140 GHz, 3-cm and 2-mm) wavebands Electron Paramagnetic Resonance (EPR) spectroscopy combined with the spin label and probe, steady-state saturation of spin-packets, and saturation transfer methods. Spin excitations formed in emeraldine form of polyaniline govern structure, magnetic resonance, and electronic properties of the polymer. Conductivity in neutral or weakly doped samples is defined mainly by interchain charge tunneling in the frames of the Kivelson theory. As the doping level increases, this process is replaced by a charge thermal activation transport by molecular-lattice polarons. In heavily doped polyaniline, the dominating is the Mott charge hopping between well-conducting crystalline ravels embedded into amorphous polymer matrix. The main properties of polyaniline are described in the first part. The theoretical background of the magnetic, relaxation, and dynamics study of nonlinear spin carriers transferring a charge in polyaniline is briefly explicated in the second part. An original data obtained in the EPR study of the nature, relaxation, and dynamics of polarons as well as the mechanism of their transfer in polyaniline chemically modified by sulfuric, hydrochloric, camphorsulfonic, 2-acrylamido-2-methyl-1-propanesulfonic, and para-toluenesulfonic acids up to different doping levels are analyzed in the third part. Some examples of utilization of polyaniline in molecular electronics and spintronics are described.
A variety of N,N-diallyl compounds, capable of undergoing cyclopolymerization, are prepared from 1,12-dodecanediamine. Selective monoformylation followed by allylation of the parent diamine afforded N,N-diallyl-N′-formyl-1,12-dodecanediamine which was converted into quaternary ammonium monomers N,N-diallyl-N-benzyl (or p-methoxybenzyl)-N′-formyl-1,12-dodecanediamine by reacting with benzyl- or p-methoxybenzyl chloride. The monomers on homo- and co-cyclopolymerization (with SO2) afforded the cationic polyelectrolytes which on acidic hydrolysis of the formyl group gave water-soluble polyelctrolytes. All the synthesized monomers, polymers, and the starting 1,12-dodecanediamine were used to study the corrosion inhibition of mild steel by gravimetry and electrochemical methods in acidic and saline media at 60°C. The inhibitor molecules (at a concentration of 400 ppm) exhibited inhibition efficiencies (%IE) in the ranges 62%–99% in 1 M HCl, 95%–99% in 4 M HCl, 13%–91% in 7.7 M HCl, 13%–91% in 0.5 M H2SO4, and 75%–90% in 3.5% NaCl. There is a dramatic increase in the IEs by the monomers and polymers in comparison to the parent diamine. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers
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