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The polymerization of aniline in the presence of mixtures of polymer sulfonic acid s has been studied. It was shown dominating influence of rigid polyacid on polymerization kinetics and electronic structure of formed polyaniline.

Drift mobility of electrons in copolymers containing pyrazolyl fragment in the main or side chain of the copolymer is studied experimentally using the time-of-flight method. The mobility is an exponential function of the applied electric field, and its values for the copolymers range from 5 × 10–7 to 2 × 10–5 cm2 V–1 s–1 at the field strength ranging from 5 × 104 to 1 × 106 V cm–1. Based on the measured mobilities and the molecule parameters, which were obtained by a PM3 quantum-chemical calculation, the role of copolymer fragments in the transport of charge carriers is discussed. [ABSTRACT FROM AUTHOR]

A template oxidative polymerization of aniline in aqueous solutions containing poly-(2-acrylamido-2-methyl-1-propanesulfonic acid) and ammonium persulfate yields a polyaniline complex with the polyacid soluble in water. According to the data of spectral measurements, the process of polymerization is of a pronounced autocatalytic nature. The consequences of this are both the formation of a nonuniform distribution of oxidized and nonoxidized fragments of the polymer chain and the formation of a macroscopic scale of redox nonuniformities in the reaction volume during the process of polymerization. The spectra of absorption of the polyaniline/polyacid films on transparent glass electrodes with a conductive layer of SnO2 and the data of potentiodynamic measurements in the potential region 0–1.0 V (Ag/AgCl) are typical for polyaniline with moderate electroconduction. [ABSTRACT FROM AUTHOR]

The electrochemical oxidation–reduction of films of polyaniline is studied in the presence of various counteranions. The differential cyclic voltabsorptometric (DCVA) curves (dA/dt relative to potential, where A is the optical absorption) are recorded at characteristic wavelengths corresponding to individual spectrum components previously isolated with the Alentsev–Fok method. The DCVA curves for aqueous solutions of HCl, HClO4, and H2SO4 at different potential scan rates are compared to traditional cyclic voltammograms. For the DCVA curves obtained at 665 nm discovered is one broad peak of dA/dt in the region of potentials between the first and second stages of polyaniline oxidation ( 0.6 V vs. Ag/AgCl). An assumption is made about a chemical nature of the process of generation of absorption in this spectral region, which, more likely than not, is connected with the emergence of dimers of radical cations of polyaniline. It is discovered that the electrochemical processes in the region of potentials that correspond to the first stage of oxidation give rise to variations in the absorption inside several regions of spectrum: 435 nm (radical cations) and 755 nm (localized polarons). An assumption is made that the first peak of the current corresponds to several successive processes that occur in a polyaniline molecule in the course of oxidation as well as to the existence of heterogeneous regions where the generation of localized polarons proceeds at different rates. [ABSTRACT FROM AUTHOR]

In this paper we have investigated organic light emitting diodes with such electroluminescent materials as aromatic polyimide, poly~N-vinylcarbazole (PVK) and dye doped PVK. N-type current–voltage characteristics with negative differential resistance for the thin polymeric and organic films are analyzed. No reasonable explanation has been provided for this phenomenon until now. Here we suggest that a polymer(organic)/metal interface containing various inhomogeneities and metal spikes is responsible for this effect. We detect also the black-body radiation, whose temperature exceeds both the melting point and the sublimation temperature of the metal of the electrode. We suppose that the current density through the spike in any cases is large enough to cause the explosion of the tip of the spike and the detected radiation has the hot plasma origin. (© 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

By using formal estimation methods, it is shown that heterogeneous redox structures, which are formed in the course of oxidation of vacuum evaporated thin polyaniline layers in the temperature range of 0–30°C, become more ordered with the increase in the oxidation temperature. [ABSTRACT FROM AUTHOR]