Polyanilines electrical

Soroudi, A., Skrifvars, M., 2012. Electroconductive polyblend fibers of polyamide-6/ pol3fpropylene/polyaniline electrical, morphological, and mechanical characteristics. Polym. Eng. Sci. 52 (7), 1606-1612. http //dx.doi.org/10.1002/pen.23074. 

Functionalized conducting monomers can be deposited on electrode surfaces aiming for covalent attachment or entrapment of sensor components. Electrically conductive polymers (qv), eg, polypyrrole, polyaniline [25233-30-17, and polythiophene/23 2JJ-J4-j5y, can be formed at the anode by electrochemical polymerization. For integration of bioselective compounds or redox polymers into conductive polymers, functionalization of conductive polymer films, whether before or after polymerization, is essential. In Figure 7, a schematic representation of an amperomethc biosensor where the enzyme is covalendy bound to a functionalized conductive polymer, eg, P-amino (polypyrrole) or poly[A/-(4-aminophenyl)-2,2 -dithienyl]pyrrole, is shown. Entrapment of ferrocene-modified GOD within polypyrrole is shown in Figure 7. 

Although polyacetylene has served as an excellent prototype for understanding the chemistry and physics of electrical conductivity in organic polymers, its instabiUty in both the neutral and doped forms precludes any useful appHcation. In contrast to poly acetylene, both polyaniline and polypyrrole are significantly more stable as electrical conductors. When addressing polymer stabiUty it is necessary to know the environmental conditions to which it will be exposed these conditions can vary quite widely. For example, many of the electrode appHcations require long-term chemical and electrochemical stabihty at room temperature while the polymer is immersed in electrolyte. Aerospace appHcations, on the other hand, can have quite severe stabiHty restrictions with testing carried out at elevated temperatures and humidities. 

Fig. 1. (a) Comparison of normalised electrical conductivity of individual MWCNTs (Langer 96 [17], Ebbesen [18]) and bundles of MWCNTs (Langer 94 [19], Song [20]). (b) Temperature dependence of resistivity of different forms (ropes and mats) of SWCNTs [21], and chemically doped conducting polymers, PAc (FeClj-doped polyacetylene [22]) and PAni (camphor sulfonic acid-doped polyaniline [2. ]) [24]. 

There are several reports of Ag nanocomposites with conducting polymers like polyaniline [38] and polypyrrole [39]. However, electrical conducting properties of green metal - starch... 

Incorporating reinforcing particles that respond to a magnetic field is important with regard to aligning the particles to improve mechanical properties anisotropically [223-226]. In related work, some in-situ techniques have been used to generate electrically conducting fillers such as polyaniline within an elastomeric material [227],... 

X. Zhang, J. Zhang, R. Wang, and Z. Liu, Cationic surfactant directed polyaniline/CNT nanocables synthesis, characterization, and enhanced electrical properties. Carbon 42, 1455—1461 (2004). 

Confinement of ion-radicals considerably changes their reactivity. What is more important for practical applications is that the confinement increases the ion-radical stability. For instance, the cation-radicals of polyanilines (emeraldines) sharply enhance their thermodynamic and kinetic stabilities when they are formed encapsulated in cucurbituril (Eelkema et al. 2007). Emeraldines have electric condnctivity as high as 1 X 10 cm (Lee et al. 2006). Encapsulation of emer-... 

Importantly, deep oxidation of polyaniline leads to a material that becomes insulating and spinless. This phenomenon was demonstrated in case of poly(fV-methylaniline) by monitoring ESR signal and electric conductivity of the sample (Wei et al. 2007). Deep oxidation results in the formation of the so-called polaron pairs that are evidenced by optical spectra. Because the hopping probability of two polarons on a single chain is too small, polaron pairs do not contribute to electric conductivity and ESR signal. 

Note 4 A polymer that shows electric conductivity due to the transport of ionic species is called an ion-conducting polymer an example is sulfonated polyaniline. When the transported ionic species is a proton as, e.g., in the case of fuel cells, it is called a protonconducting polymer. 

In potentiometric sensors, an electrical potential between the working electrode and a reference electrode is measured at zero current conditions in a solution containing ions that exchange with the surface. The first potentiometric MIP sensor was prepared in 1992 by Vinokurov (1992). The substrate-selective polyaniline electrode was electrosynthesized with polypyrrole, polyaniline, and aniline-p-aminophenol copolymers. The development of an MIP-based potentiometric sensor was reported in 1995 by Hutchins and Bachas (1995). This potentiometric sensor has high selectivity for nitrite with a low detection limit of (2 + l)x 10 M (Fig. 15.10). 

Polyaniline is a repeating unit of benzene rings each joined by an N—H group (13, Fig. 13.7). This polymer and its derivatives are of interest because they are electrically conductive when doped with oxidants. This material is prepared by oxidation of aniline electrochemically, ° enzymaticaUy, or with simple chemical reagents. Polyaniline can be formally regarded as a polymer of... 

Electrically conducting polymer particles such as polypyrrole and polyaniline could also be prepared by dispersion polymerization in aqueous ethanol (31). The oxidation polymerization of pyrrole and aniline has been carried out at the electrode surfaces so far and formed a thin film of conducting polymer. On the other hand, polypyrrole precipitates as particles when an oxidizing reagent is added to a pyrrole dissolved ethanol solution, which contains a water-soluble stabilizer. In this way electrically conducting polymer particles are obtained and, in order to add more function to them, incorporation of functional groups, such as aldehyde to the surface, and silicone treatment were invented (32). 

An extensive review of the synthesis of rc-conjugated polymers is presented using a tutorial approach to provide an introduction to the field intended for the undergraduate student and the experienced chemist alike. The many synthetic methodologies that have been used for the synthesis of conjugated polymers are outlined for each class of polymers with a focus on research from the 1990s. The effect of structure on electrical properties is detailed. Specific systems reviewed include the polyacetylenes, polyanilines, polypyrroles, polythiophenes, poly(arylene vinylenes), and polyphenylenes. 

This technique could be combined with the in situ approach by generating metal or metal oxide magnetic particles in a magnetic field,75,76 for example by the thermolysis or photolysis of a metal carbonyl. As mentioned earlier, some related work involved the use of in situ techniques to generate electrically conducting fillers such as polyaniline within PDMS.28... 

In addition to the conventional lithographic techniques, surface patterning was performed by means of local polymerisation of the monomers under the SPM tip. These studies have been mainly focused towards electrically conductive polymers such as polypyrole, polythyophene and polyaniline. The easiest way to implement polymerisation is to set either the tip or sample potential sufficiently positive to cause the electrochemical oxidation of the monomer [438, 451 -455]. This technique enabled controlled removal and deposition of polymer dots as small as 1 nm to in a well defined pattern [453]. After deposition, the dots could be read using a conventional imaging mode (Fig. 49). 

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