Electrochemical Solid‐State Studies on Oligomeric p‐Phenylenes as Model Compounds for Conductive Polymers

Abstract

Reversible reductions and oxidations at separated potentials are possible electro‐chemically in the solid state up to the tetraanion and tetracation respectively in the case of sexiphenyl. However, at room temperature and depending on the electrode potential the formation of more or less strongly cross‐linked polymer chains is observed during the oxidation. In addition, the measurements prove that the characteristic current plateaus in the voltammograms of conductive polymers are attributable to faradaic redox processes.

Electrochemical and morphological characterization of poly[(R)-(−)-3-(l-pyrrolyl)propyl-N-(3,5-dinitrobenzoyl)-α-phenylglycinate] films deposited on ITO electrodes

“…The difference (DEp) between anodic and cathodic peak potentials was ca. 0.15 V, a value that is commonly observed for conducting polymers and is assigned to structural reorganization processes within the film [31].…”

Electrochemistry and photoelectrochemistry of two donor–acceptor polythiophene polymers with acceptor moieties in the main chain

“…The peak broadening is well known for conducting polymers and especially various polythiophenes and is usually attributed to structural changes occurring after the doping [35]. For instance, it is usually less pronounced for cathodically doped polymers, which can be explained by different localization of HOMO and LUMO in polythiophenes (HOMO on the ''polyacetylene-like'' CH backbone and LUMO on sulfur) and much less pronounced tendency of p-dimerization for thiophene radical anions, as opposed to thiophene radical cations [36].…”

“…Yet another approach is to use the peak potentials or the formal potentials determined as a half-sum of the potentials of the doping and undoping peaks. This approach has its advantages and disadvantages, the main problems being the dependence of the peak potentials on the scan rate, the pronounced asymmetry of the doping and undoping peaks typical to conducting polymers and associated with the presence of polymer segments with very different conjugation lengths, as well as the above-mentioned structural reorganization upon doping [35]. In view of these problems, Loganathan et al [43] proposed that the formal potentials for p-and n-doping of conjugated polymers should be taken as the potentials at the half of the undoping current on the cathodic (for p-doping) or anodic (for n-doping) side of the undoping wave.…”

Voltammetric characterization of soluble polyacetylene derivatives obtained from the ring-opening metathesis polymerization (ROMP) of substituted cyclooctatetraenes

“…This problem has attracted much debate in the literature, 39 " 42 but many agree that for such systems the faradaic charge cannot be extracted from the voltammetric data alone.…”