Polyfuran, conducting polymers

Fig. 1 Building units of conducting polymers, (1) polyacetylene (PA) (2) polypyrrole (PPy), polythiophene (PTh), polyfurane (PFu) (3) polyphenylene (PP) (4) polyaniline (PANI) 5 polyindole (PIND) (6) polycarbazole (PCaz) (7) polyazulene (Paz) (8) polynaphthalene (PNa) (9) polyanthracene (PAnth) (10) polypyrene (PPyr) (11) polyfluorene (PFiu) (12) poly(isothionaphthalene) (PITN) (13) poly(dithienothiophene) (14) poly(thienopyrrole) (15) poly(dithienylbenzene) (1G) poly(3-alkylthiophene) (17) poly(phenylene vinylene) (18) poly(bipyrrole) (PBPy), poly(bithiophene) (PBT) (19) poly(phenylenesulfide) (20) 4-poly(thienothiophene) (21) poly(thienyl vinylene), poly(furane vinylene) (22) poly(ethylenedioxythiophene) (PEDOT).

All conducting polymers (and most of their derivatives), for example, poly(paraphenylene), poly(phenylene vinylene), polypyrrole, polythiophene (PT), polyfuran, poly(heteroaromatic vinylenes), and polyaniline (Fig. 29.1), undergo p- and/or n-redox doping. 

Conducting polymers such as polyfuran and polythiophene may have valuable uses in humidity sensors and radiation detectors as the conductivity of these doped polymers varies considerably when exposed to humidity or radiation. 

Polypyrrole, polythiophene, polyaniline, polyfuran, polyacetylene, and poly-methylthiophene may exhibit a mixed electronic and ionic conductivity, similar to inorganic intercalation, or insertion compounds [43]. In the conductive form these polymers are partly oxidized and these positive charges are equilibrated by inorganic anions, which can diffuse through the polymer net. Alternatively, the conductive polymers can be partly reduced, with cations as counter ions. The eleetronic conductivity originates Irom partial oxidation of conjugated jt-bonds. The positive charge... 

Among all the methods of synthesis to produce polypyrrole, the electrochemical procedure is, with difference, the most useful to obtain polypyrroles having high conductivities. The general details of electrochemical synthesis of polypyrrole are similar to other conducting polymers such as polythiophene or polyfurane. The flow of an anodic current in a simple electrochemical cell, through a solution containing a... 

The discovery of highly conducting poly acetylene in 1977 [1] prompted the synthesis of other polymers with conjugated 7r-systems such as polypyrrole [2], poly-p-phenyl-ene [3], poly-p-phenylenevinylene [4], polyphenylenesulflde [5, 6], polyaniline [7], as well as of other poly heterocycles such as polythiophene [8], polyfuran [8], poly-selenophene [9], or more extended polyaromatics such as polyazulene [10]. Because they can have a variety of structural variations, polythiophenes have become the type of conducting polymer most frequently investigated because conductivity is mostly unaffected by substituents [11]. In addition, both conducting and semiconducting polythiophenes are very stable and readily characterized. 

While oxidation of furan yields ill-defined polymers with severely interrupted Jt-conjugation, oxidation of 2,2, 5, 2"-terfuran 1 ( = 3) does produce fully jt-conjugated polyfuran films. These films, when doped with tri-fluoromethanesulfonate ions, exhibit conductivities of up to 2 x lO Scm and a gap of 2.35 eV between the... 

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