Stability of Conducting Polythiophene and Derivatives

Abstract

Many organic conducting polymers such as polyacetylene, PA (1) ; polyparaphenylene, PPP (2) ; polyparaphenylenesulfide, PPS (2); and polypyrrole, PP (3) have been proposed in the literature. These polymers show reversibility of the doping-undoping process, making them of interest in energy storage. One of the key problems, however, is the poor stability of most of these polymers. Polyacetylene, PA, must be prepared and stored under a rigorously O2 free atmosphere and at a low temperature (4). Polypyrrole, PP, although st~able in its conducting state, is also sensitive to 02 in its semiconducting undoped state (5). As a matter of fact, a progressive redoping by 02 occurs due to the value of the polymer oxidation potential (Eox ~ --0.3) which lies in the same range as that for the reduction of O2.PPP and PPS show a higher oxidation stability mainly in the undoped state (Eox ~ ~l.6V), and their sensitivity to O2 is less pronounced, but information on the doped state is scarce. The authors recently reported the electrochemical generation of thin films of new organic conducting polymers, polythiophene, polyfuran, and derivatives (6) which also appear as interesting candidates for organic electrodes for energy storage or display.In this paper, the stability characteristics of these new polymers is presented under various experimental conditions (02, H~O, H +, OH-, temperature).

Synthesis and Thermoelectric Properties of Polycarbazole, Polyindolocarbazole, and Polydiindolocarbazole Derivatives

“…[38][39][40] It is important to note that the conductivities obtained by doping with FeCl 3 can also be limited by the oxidation potential of the polymers. However, it is more interesting to use a medium strength dopant such as ferric chloride or ferric tosylate, compared to nitrosonium salts (NOBF 4 or NOBF 6 ) where overoxidation and degradation often becomes a problem.…”

Conducting polymer-hydrogels for medical electrode applications

“…Although recent research has shown that the emeraldine salt of PANI (EPANI) can be successfully fabricated in a biocompatible form [73,74], modern biomedical CPs are typically composed of heterocyclic aromatics, such as derivatives of thiophene and pyrrole [75][76][77][78]. Specifically, poly(3,4-ethylenedioxythiophene) (PEDOT) and polypyrrole (PPy) have been widely studied for their superior environmental and electrochemical stability [79][80][81][82]. Figure 2 shows the chemical structure of various thiophene derivatives including EDOT, EDOT-MeOH and 3-alkylthiophene.…”

Electrochemical materials science: calculation vs. experiment as predictive tools in tailoring intrinsically conducting polythiophenes

“…Platinum electrodes were used because of their inert behavior against monomers and polymers. In addition, polymers generated on platinum electrodes show in general higher conductivities than films generated on any other electrodes [15,17,113,114]. penetrate into the film due to its smaller size [65].…”

“…Since the first reports of the oxidation of pyrrole, many other aromatic systems have been found to undergo electropolymerization to produce conducting polymers, like thiophene [14][15][16][17], furan [14], selenophene [18], aniline [19][20][21][22], azulene [23,24], indole [14], Paraphenylene [25,26], as well as many substituted, multi-ring and polynuclear aromatic hydrocarbon systems (Table 1). It was found that all of the resulting polymers have a conjugated backbone, which is required for conductivity.…”