Spectroelectrochemical study of poly-3,4-ethylenedioxythiophene films in the presence of different supporting electrolytes

Steady-state absorption spectra of poly-3,4-ethylenedioxythiophene (PEDOT) films at different oxidation degrees and their differential cyclic voltabsorptograms are studied in 0.1 M LiClO₄, Bu₄NBF₄, and Bu₄NPF₆ solutions in acetonitrile. Three major absorption bands are obtained in the film electronic spectra: a complex band with a pronounced maximum at λ = 600 nm that corresponds to π → π* electronic transitions in reduced fragments of a PEDOT film and two absorption bands (at λ_max = 850 nm and λ_max > 1100 nm) corresponding to two oxidized film fragments. It is shown that the position and shape of absorption bands are practically independent of the nature of dopant anions, which points to the absence of pronounced interactions with positively charged polymer fragments. An attempt is made to analyze the obtained spectroelectrochemical data qualitatively to estimate the extinction coefficients and concentrations of absorbing particles and their variation in the course of redox processes.     

Synthesis and structure of poly-3,4-ethylenedioxythiophene film with the inclusions of palladium nanoparticles

By chemical deposition of ultrafine particles of metallic palladium on the polymer matrix of poly-3,4-ethylenedioxythiophene (PEDOT) composite PEDOT/Pd films were obtained. The conditions of synthesis of the composite films in dependence on the duration of exposure of the reduced form of PEDOT film in a solution of palladium chloride, its concentration and the film thickness were studied. By the methods of scanning electron microscopy (SEM) and transmission electron microscopy (TEM) it was shown that in the process of the synthesis of the composite films the nanosized palladium particles of predominantly quasispherical shape precipitated on the globular structure of the polymer. The size of the palladium nanoparticles in the composite PEDOT film and the nature of their distribution over the film bulk were revealed. An increase in the duration of deposition of the palladium nanoparticles on the film was shown to lead to an increase in their size and in the density of particles in the film.     

Radiative π0 photoproduction on protons in the Δ+ (1232) region

The reaction γp → pπ ⁰γ′ has been measured with the Crystal Ball/TAPS detectors using the energy-tagged photon beam at the electron accelerator facility MAMI-B. Energy and angular differential cross-sections for the emitted photon γ′ and angular differential cross-sections for the π⁰ have been determined with high statistics in the energy range of the Δ⁺ (1232)-resonance. Cross-sections and the ratio of the cross-section to the nonradiative process γp → pπ ⁰ are compared to theoretical reaction models, having the anomalous magnetic moment κ _Δ as free parameter. As the shape of the experimental distributions is not reproduced in detail by the model calculations, currently no extraction of κ _Δ is feasible.     

Vlasov Scaling for Stochastic Dynamics of Continuous Systems

We describe a general derivation scheme for the Vlasov-type equations for Markov evolutions of particle systems in continuum. This scheme is based on a proper scaling of corresponding Markov generators and has an algorithmic realization in terms of related hierarchical chains of correlation functions equations. Several examples of realization of the proposed approach in particular models are presented.     

On the metrical properties of the configuration space

We study some topological and metrical properties of configuration spaces. In particular, we introduce a family of metrics on the configuration space Γ, which makes it a Polish space. Compact functions on Γ are also considered. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Spectral Analysis of a Stochastic Ising Model in Continuum

We consider an equilibrium stochastic dynamics of spatial spin systems in ℝ ^d involving both a birth-and-death dynamics and a spin flip dynamics as well. Using a general approach to the spectral analysis of corresponding Markov generator, we estimate the spectral gap and construct one-particle invariant subspaces for the generator. Dedicated to our admired teacher and friend Robert Minlos on occasion of his 75th birthday. The financial support of SFB-701, Bielefeld University, is gratefully acknowledged. The work is partially supported by RFBR grant 05-01-00449, Scientific School grant 934.2003.1, CRDF grant RUM1-2693-MO-05.     

Relationships Between the Ultimate Strengths of Polymer Composites in Static Bending,Compression, and Tension

Mechanics of Composite Materials - Relationships between the ultimate static bending, compressive and tensile strengths of polymer composite materials are investigated. Validity of the assumptions...     

Oxidation of hydrazine on poly-3,4-ethylenedioxythiophene polymer films with inclusions of palladium nanoparticles

The oxidation of hydrazine on poly-3,4-ethylenedioxythiophene (PEDOT/Pd) composite films was studied. The films were obtained by chemical deposition of palladium into a PEDOT polymer matrix. The structure of the films was characterized by electron microscopy. The effect of hydrazine concentration and amount of deposited palladium on the oxidation of hydrazine in phosphate buffer solutions (pH 6.86) was investigated.