Conducting polymers poly -thiophene

F. B. A. Li, W. J. Albery, Electrochemical deposition of a conducting polymer, poly(thiophene-3-acetic acid) the first observation of individual events of... 

Thus, from a solid-state chemistry point of view, the conducting polymer poly-3-methyl thiophene is in the reduced state, a semiconductor with a band structure. Intercalating with ions and oxidizing makes the compound behave as a metal from 0.45 to 1.1 Von theNHS. 

Electron-conductive polymers, poly(pyrroles), poly(thiophenes), poly-(furan), poly(quinoline), and poly(benzo[c]thiophene) 90MI22 91MI56. 

Taliani, C., et al. 1989. Optical properties of a low energy gap conduction polymer Poly-dithieno [3,4-b 3, 4 -d] thiophene. Synth Met 28 C507. 

A last point remains unresolved. Does the coupling result from the direct reaction between two radical-cations, as generally accepted for other conducting polymers poly (pyrrole), poly(thiophene), poly(ani-line)), or from a mixed reaction between benzene and the corresponding radical-cation ... 

Since 3-substituted thiophene is easily synthesized, many studies have been devoted to its preparation and characterization. In particular, polythiophene bearing a long alkyl chain on the 3 position showed a very interesting structure and properties. Poly(3-dode-cylthiophene) was electrochemically prepared and the degree of polymerization was found to be 90 by vapor pressure osmometry [6,39]. Its conductivity was 67Scm . This is the first report on soluble conductive polymer. Poly(3-dodecylthiophene) showed bipolaron spectra in a chloroform solution and absorbance was linearly dependent on the concentration... 

A number of approaches are available to improve the morphology and homogeneity of electrochemically deposited conducting polymer films. Priming of the electrode surface with a monolayer of adsorbed or covalently bonded monomer leads to more compact deposits of polyaniline,87,88 poly thiophene,80 and polypyrrole.89,90 Electrode rotation has been shown to inhibit the deposition of powdery overlayers during poly(3-methylthiophene) deposition.81... 

The huge literature on the electronic conductivity of dry conducting polymer samples will not be considered here because it has limited relevance to their electrochemistry. On the other hand, in situ methods, in which the polymer is immersed in an electrolyte solution under potential control, provide valuable insights into electron transport during electrochemical processes. It should be noted that in situ and dry conductivities of conducting polymers are not directly comparable, since concentration polarization can reduce the conductivity of electrolyte-wetted films considerably.139 Thus in situ conductivities reported for polypyrrole,140,141 poly thiophene,37 and poly aniline37 are orders of magnitude lower than dry conductivities.15... 

In this paper we describe the preparation of thin polymer films by surface catalysis and anodic deposition. The results indicate that both synthesis routes produce orientationally ordered films that have similar infrared spectra. It is also shown that thin ordered films of poly(thiophene) have different electrochemical behavior than the fibrous films that are electrically conducting. 

Conductive polymers have attracted increasing attention because they have wide applications. Recently, very stable poly(thiophenes) with polyfluorinated side chains have been electrochemically synthesized and characterized [81]. Furthermore, notably novel conductive materials have been prepared by cathodic electropolymerization of perfluoro cvclobutene and cyclopentene [82]. 

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... 

In 1961, Gewald and co-workers published the synthesis of poly-substituted thiophenes involving condensation of cyanoacetate and elemental sulphur with ketones or aldehydes in a three-component reaction (Scheme 5.9). Beyond their industrial use in dyes and conducting polymers, 2,5-substituted thiophenes have shown extensive potential in the pharmaceutical industry. Most published Gewald thiophene synthetic procedures require reaction times between 8 and 48 h for the condensation step. Hoener and... 

Against this background of infusible conducting polymers, the development of the soluble polythiophenes is most interesting. Glass transition temperatures have been reported as 48 °C for poly(3-butylthiophene) and 145 °C for poly(3-methyl-thiophene) 261). These polymers also show crystallinity in films and can be crystallized from solution. Solution studies indicate that there are two chain conformations 262) and the availability of a non-conjugated conformation may be a key to the low transition temperatures and solubility, when compared to the stiff-chain conjugated polymers. 

Another class of conducting polymer that has been examined for resonant nonlinear response are the poly(thiophene) polymers. DFWM has been reported for poly(alkyIthiophene) and for several model... 

In the second approach to self-assembly of polymer-silica nanocomposites, polymerizable surfactants are employed both to direct self-assembly into ordered mesophases and to serve as organic monomers which can be subsequently polymerized. For instance, Brinker et al. developed nonionic surfactants incorporating diacy-telene groups which could be polymerized upon irradiation by UV light.68 69 Similarly, poly(thiophene)70 and poly(pyrrole)71 have been successfully integrated into silica nanostructures in this manner. Importantly, this in situ polymerization produces isolated molecular wires, rather than clustered bundles of conductive polymer.70... 

Conducting polymers, such as poly (aniline), poly(pyrrole) or poly(thiophene) (Figure 7.1) have a conjugated system of delocalized it -orbitals, which allows conduction to occur in the oxidized, or doped polymer. 

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