Electrically active polymers properties

There is another type of electrically active polymer that is known as the electroconductive polymer, in which polymer chains contain long conjugated double bonds, and this chemical structure adds electroconductive properties to the polymers. In these cases, the electrically induced deformation is considered to have originated from the electrochemical reactions such as the oxidation and reduction of the polymer chain. For the deformation, some additives such as dopants have been known to be necessary for effective actuation. Therefore, the electrical actuation of these materials has been... 

Janet S. S. Wong, University of Illinois, Urbana, Illinois, Scratch Behavior Bernhard Wunderlich, University of Tennessee, Chemical Sciences Division of Oak Ridge National Laboratory, Thermodynamic Properties Albert F. Yee, University of Michigan, Ann Arbor, Michigan, Impact Resistance Peter Zarras, Naval Air Warfare Center Weapons Division (NAWCWD), China Lake, California, Electrically Active Polymers... 

Conjugated polymers, including optically active polymers and dendronized polymers that are very useful in electrical and optical fields and asymmetric catalysis, will continue to attract interest from chemists and materials scientists. It is well anticipated that more and more polymers with interesting structures and properties will be synthesized from the transition metal coupling strategy. 

In order to satisfy the industrial demand, the performance of supercapacitors must be improved and new solutions should be proposed. The development of new materials and new concepts has enabled important breakthroughs during the last years. In this forecast, carbon plays a central role. Due to its low cost, versatility of nanotextural and structural properties, high electrical conductivity, it is the main electrode component. Nanoporous carbons are the active electrode material, whereas carbon blacks or nanotubes can be used for improving the conductivity of electrodes or as support of other active materials, e.g., oxides or electrically conducting polymers. 

Semiconductor and metallic nanoparticles have been extensively studied as active components in wide variety of basic research and technological applications due to their new or improved optical, electric, and magnetic properties compared to their bulk counterparts [1]. Therefore, exploitation of well-known materials in their new nanosized forms is strongly motivated area of research. Prussian Blue [2], an old pigment, is a coordination polymer formed by reaction of either hexacyanoferrate(II) anions with ferric (Fe(III)) cations, or hexacyanoferrate(III) anions with ferrous (Fe(II)) cations [3], According to X-... 

The discovery that doped forms of polypyrroles conduct electrical current has spurred a great deal of synthetic activity related to polypyrroles [216-218], Reviews are available on various aspects of the synthesis and properties of polypyrroles [219,220]. In addition, summaries of important aspects of polypyrroles are included in several reviews on electrically conducting polymers [221-226]. Polypyrrole has been synthesized by chemical polymerization in solution [227-231], chemical vapor deposition (CVD) [232,233], and electrochemical polymerization [234-240]. The polymer structure consists primarily of units derived from the coupling of the pyrrole monomer at the 2,5-positions [Eq. (84)]. However, up to a third of the pyrrole rings in electrochemically prepared polypyrrole are not coupled in this manner [241]. 

Considerable interest has been focused on both polymer-polymer mixtures and mixtures of polymers with low molecular weight solvents. Polymer-solvent systems have been extensively investigated in the solution range where the mixture contains an appreciable amount of solvent. Much less attention has been devoted to systems containing only a small amount of solvent which is then usually called additive. These systems are interesting from both an academic and industrial point of view. In fact, additives are widely used to affect the mechanical, thermal, electrical and optical properties of polymers. The mechanism by which additives become active is important not only because it enables us to understand the properties of the mixture, but also frequently because of its relevance to the pure polymer component. 

The mechanisms of the thermal and photochemical degradation of poly(vinyl chloride) (PVC) continue to be active areas of research in polymer chemistry mainly because its high chemical resistance, comparatively low cost and wide variety of application m e PVC one of the most widely used thermoplastic materials. The wide variety of forms which the material can take includes pastes, lattices, solutions, films, boards and moulded and extruded pieces and depends to a very large extent on the good electrical and mechanical properties of the polymer. In spite of these advantages the even wider application of the material has been restricted by its low thermal and photochemical stability. Thermal instability is a problem since processing of the polymer is carried out at about 200 C and the photochemical instability places a limit on the extent of the outdoor applications which can be developed. 

Today the number of electroactive polymers has grown substantially. There currently exists a wide variety of such materials, ranging from rigid carbon-nanotubes to soft dielectric elastomers. A number of reviews and overviews have been prepared on these and other materials for use as artificial muscles and other applications [1, 2, 7, 10, 11, 13-28]. The next section will provide a survey of the most common electrically activated EAP technologies and provide some pertinent performance values. The remainder of the paper will focus specifically on dielectric elastomers. Several actuation properties for these materials are summarized in Table 1.1 along with other actuation technologies including mammalian muscle. It is important to note that data was recorded for different materials under different conditions so the information provided in the table should only be used as a qualitative comparison tool. 

Most work related to the covalent labeling of proteins with organometallic is related to the development of enzyme or antibody amperometric biosensors. For the majority of redox enzymes, the active center (or redox-aetive cofactors) are buried inside the protein and are therefore electrically inaccessible for direct electron transfer to the electrode surface of an amperometric biosensor. This problem has been resolved by (i) addition of a diffusional redox-active mediator, (ii) covalent tethering of the mediator to the protein, or (iii) immobilization of the protein in a redox-active polymer. Ferrocenyl derivatives have frequently been used in all three formats as mediators because of their almost ideal electrochemical properties. 

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