Polyaniline chemical structure

As with the bulk polyaniline sample, it was decided to perform hydrogen sorption measurements close to room temperature. Since the nanospheres do not contain any hydrogen after synthesis, with the exception of the chemically bonded hydrogen that is part of the polyaniline chemical structure, the first hydrogen measurement performed was absorption. The sample was kept under vacuum and then exposed to 80 bar of hydrogen pressure. Each absorption measurement was then followed by a desorption measurement at 30 °C and given enough time to reach an equilibrium. The results of the kinetic absorption and desorption measurements are shown in Fig. 8.14. 

In a complementary study of the interaction between polyanilinc and ITO, oligomeric polyaniline model compounds, namely phenyl-capped amino (PC2) and imino (PC20X) dimers [113, 114] have been used. The chemical structures of the polyaniline oligomers are displayed in Figure 5-20. Both substances are soluble in... 

Polyaniline provides the prototypical example of a chemically distinct doping mechanism [33,34], Protonation by acid-base chemistry leads to an internal redox reaction and the conversion from semiconductor (the emeraldine base) to metal (the emeraldine salt). The doping mechanism is shown schematically in Fig. II-2. The chemical structure of the semiconducting emeraldine base form of polyaniline is that of an alternating copolymer, denoted as [(1A)(2A)] , with... 

Polyaniline (PANI) has complicated chemical structures that arc postulated [90,91]. To study such postulated structures Kaplan et al. [92] and Richter et al. [93] made solid state " C and NMR [92] and N NMR [93] and an emeraldine base (EB), a leucoemer-aldine base (LEB) and an emeraldine hydrochloride (ES), and revealed that EB is an alternating co-polymer... 

Figure 1.1 Chemical structures for monomers of the conjugated polymers discussed in this chapter (a) vinylene (the repeat unit of polyacetylene) (b) ethynylene (polydiacetylene is alternating vinylene-ethynylene) (c) phenylene (d) thiophene (e) leucoemeraldine form of polyaniline (f) pernigraniline form ofpolyaniline (the number of protons can vary between the...

Interestingly, polymer 18 was found to emit blue-purple light. Aromatic oxadiazole compounds are known to show blue electroluminescence (40-42), Main chain oxadiazole polymers can also be made fluorescent by proper modification of the chemical structure. Pei and Yang (43,44) have reported a new oxadiazole polymer 25 with both a flexible linkage and solubilizing alkoxy side-chains (Scheme 7). An LED of structure ITO/polyaniline/polymer 25/Al has an external quantum efficiency close to 0.1 % and a tum-on voltage around 4.5 V. 

PTh), poly(p-phenylene) (PPP), poly(p-phenylene vinylene) (PPV), polyaniline (PANI), and their analogues were also evolved [15-17,28-36]. Ihe chemical structures of constitutional units of undoped forms of some very common CPs are shown in Figure 1.1. 

Figure 15.7 Chemical structure of (a) polyaniline (leu-coemeraldine), (b) polypyrrole, and (c) poly(ethylene dioxythiophene).

Figure 8.3 Typical cyclic voltammogram (upper), redox behavior in chemical structures (middle) and expansion and contraction of polyaniline film along the stretched direction (lower). E and E are the anodic peak and cathode peak, respectively, 1/2, ls-es = 1/2 ( + EJ.

FIGURE 8.1 Chemical structure of (a) polystyrene (PS), (b) poly(methyl methacrylate) (PMMA), (c) 8-hydroxyqui-noline (8HQ), (d) 1-dodecanethiol (DT), (e) 2-naphthalenethiol (2NT), (f) polyaniline (PANI), (g) tetrathiafiilvalene (TTF), and (h) methanofullerene [6,6]-phenyl C61-butyric acid methyl ester (PCBM). 

Polyaniline, PAni Polypyrrole, PPy Polythiophene, Pth Scheme 2. Chemical structures of three important CPs (neutral state). 

Figure 1.17 Chemical structures of (A) self-doped ring-sulfonated poly aniline and (B) dedoped (insulating) salt form of ring-sulfonated polyaniline. (Reprinted with permission from Journal of the American Chemical Society, 112, 2800. Copyright (1990) American Chemical Society.)...

FIGURE 13.5 Schematic diagram showing the chemical structure, synthesis, reversible acid/hase doping/dedoping, and redox chemistry of polyaniline. Reprinted with permission from [82]. Copyright 2008 American Chemical Society. 

Figure 4-1. Chemical structures of conducting polymers, (a) Frans-polyacetylene (b) cw-polyacetylene (c) poIy(/i-phenylene) (d) polypyrrole (e) polythiophene (f) poly(/>-phenylenevinylene) (g) poly(2,5-thienylenevinylene) (h) polyaniline (leucoemeraldine base form) (i) polyisothianaphthene.

Conducting polymers are chemically characterized by the so-called conjugation, in which carbon double bonds alternate with carbon single bonds along a polymer backbone. The chemical structures of two examples of conducting polymers, polypyrrole (PPy) and polyaniline (PANi), are reported in Fig. 6.101. 

The chemical structure of polyaniline in various oxidation states is shown in Figure 3. The fully reduced form is referred to as leucoemeraldine base (LEB) while the fully oxidized form is called pemigraniline (PNB). Both LEB and PNB will shift towards the EB form upon exposure to an oxidizing environment.[2] Although it is well known that the oxidation state of polyaniline is an important characteristic of this polymer, there are few reports of its influence on the development of morphology in fibers and films. Previous work has shown that both films and fibers produced from solutions of leucoemeraldine base in N,N -dimethyl propylene urea (DMPU) exhibit crystallinity and a melting transition.[12]... 

Polyaniline and its derivatives have been widely used for biosensing applications based on their crystallinity. For example, PANi and its derivatives were found responding to the saturated alcohol vapors by undergoing a change in resistance [54]. The change in resistance of the polymers on exposure to different alcohol vapors was attributed to their chemical structure, chain length, and dielectric nature. 

Fig. 3.1 Schematic chemical structures of polyacetylene, polyaniline, and polypyrrole.

Structures 1, 2, and 3 are neutral forms of polyaniline, and structure 4 represents the normal chemical transition after doping by HCl. The more complicated structure 5 includes amine as well as quinoidal and quaternary imine nitrogen subunits. After immersion in electrolytes and the corrosion process begins, the ratio among these three kinds of subunits in structures 4 and 5 will change, and these changes can be detected by XPS. 

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