Polymer polyfurane

Polypyrrole, poly thiophene, polyfuran, polycarbazole, polystyrene with tetrathi-afulvalene substituents, polyethylene with carbazole substituents, and poly-oxyphenazine as electrochemically active polymers for rechargeable batteries 97CRV207. 

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).

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... 

The solution coating technique was used in the preparation of the cellulose triacetate membrane discussed above. A solution of cellulose triacetate in chloroform was deposited on the porous support and the solvent was then evaporated leaving a thin film on the porous support. Thin film polymerization was used to prepare a polyfuran membrane barrier layer on polysulfone. In this case, the monomer furfuryl alcohol is polymerized in situ by adjustment of pH and temperature. This membrane proved to be highly susceptible to oxidizing agents and is of limited value. By far the most valuable technique in the formation of membrane barrier layers is interfacial polycondensation. In this method, a polymer is formed on the porous support surface at the interface of organic and aqueous phases by reaction of specific molecules dissolved in each phase. It is by this method that a number of polyamides and polyurea membrane barrier layers have been formed on polysulfone. Elements containing these membranes are available commercially. 

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. 

Vibrational spectroscopy has been applied to the study of molecular structure and physical properties of conjugated polyfurans <92CPL(l9l)419, 93JCP(98)769, 93SM(57)4467>. Vibrational spectra provide simultaneous and selective information on the structure of a polymer and on its charge distribution. Interpretation of experimental data is performed with the assistance of lattice dynamics calculations. 

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... 

Despite numerous attempts at synthesizing the ideal polymer 34 [4d, 49, 50] the preparation of polyfuran has not been a clear-cut issue in terms of stmctural assessment and material performance. 

Nation—sulfonated tetrafluoroethylene (PTFE) copolymer polyester—polyethylene terephtheilate (PET) polyfuran— heterocyclic polymers based on the tive-membraed heteroaromatic ring compounds Teflon—polytetrafluoroethylene (PTFE)... 

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. 

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