Conducting polymer doped polyaniline

Properties of representative conducting polymers. Doped conjugated polymers have generated substantial interest in view of possible applications such as lightweight batteries, antistatic equipment, and microelectronics to speculative concepts such as molecular electronic devices.37-38 These polymers include doped polyacetylene, polyaniline, polypyrrole, and other polyheterocycles (Figure 5). While the conduction mechanism of metals and inorganic semiconductors is well understood and utilized in microelectronics, this is not true to the same... 

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]. 

The stoichiometry of the redox reactions of conducting polymers (n and m in reactions 1 and 2) is quite variable. Under the most widely used conditions, polypyrroles and polythiophenes can be reversibly oxidized to a level of one hole per ca. 3 monomer units (i.e., a degree of oxidation, n, of ca. 0.3).7 However, this limit is dictated by the stability of the oxidized film under the conditions employed (Section V). With particularly dry and unreactive solvents, degrees of oxidation of 0.5 can be reversibly attained,37 and for poly-(4,4 -dimethoxybithiophene), a value of n = 1 has been reported.38 Although much fewer data are available for n-doping, it appears to involve similar stoichiometries [i.e., m in Eq. (2) is typically ca. 0.3].34,39"41 Polyanilines can in principle be reversibly p-doped to one... 

HPA-composite catalysts have also been studied for ORR.166 A conducting polymer and HPA were combined to form the 12-phosphormolibdic acid-doped polyaniline-V202 composite. The composite showed improved activity over the conducting polymer alone in a weak acid solution. 

Conducting polymers such as PEDOT PSS, doped polyaniline or polypyrrole, and... 

Conducting Polymers, PEDOT-PSS, Doped Polyaniline and Polypyrrole... 

Polyacetylene has good inert atmospheric thermal stability but oxidizes easily in the presence of air. The doped samples are even more susceptible to air. Polyacetylene films have a lustrous, silvery appearance and some flexibility. Other polymers have been found to be conductive. These include poly(p-phenylene) prepared by the Freidel-Crafts polymerization of benzene, polythiophene and derivatives, PPV, polypyrrole, and polyaniline. The first polymers commercialized as conductive polymers were polypyrrole and polythiophene because of their greater stability to air and the ability to directly produce these polymers in a doped form. While their conductivities (often on the order of 10" S/m) are lower than that of polyacetylene, this is sufficient for many applications. 

In the context of this chapter, we focus on the undoped or lightly doped 7i-conjugated systems that are commonly referred to as organic semiconductors. Conducting polymers, such as PEDOT PSS, plexcore, polyaniline, polypyrrole, and others are not addressed here as their charge transfer mechanisms are rather different and would warrant an article in its own right. 

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... 

LB films prepared from poly-thiophene-3-acetic acid stearylamine or sulfonated polyaniline stearylamine polyion complexes, transferred to substrates, and doped by SbCls Absorption and infrared spectra, X-ray diffraction, and conductivity measurements Lateral d.c. conductivities of doped films were moisture dependent and were as high as 2 S cm"molecular organization consisted of randomly oriented polymers lying as extended chains parallel between the substrates and sandwiched between layers of stearylamine molecules whose chains were interdigitated 772... 

The use of ISEs with ion-selective membranes based on plasticized PVC, as well as glass pH electrodes, is limited to the analysis of aqueous solutions. On the other hand, sensors based on conducting polymer membranes are usually insoluble in organic solvents, which extends the range of possible applications. Electrosynthesized polypyrrole doped with calcion works as a Ca2+ sensor that can be applied as indicator electrode in the titration of Ca2+ with NaF in mixed solvents, such as water-methanol (1 1) and water-ethanol (1 1) [52], Another example is the use of polyaniline as indicator electrode in order to follow the acid-base precipitation titration of trimeprazine base with tartaric acid in isopropanol solution (see Procedure 5). 

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