New nanocomposites of polystyrene with polyaniline doped with lauryl sulfuric acid.

This work is concentrated on synthesis and investigation of new core-shell nanocomposites of polystyrene (PS) with doped polyaniline (PANI). The latex containing PS nanoparticles with sizes of 15-30 nm was prepared by microemulsion polymerization of styrene in water media. The PS/PANI nanocomposites were synthesized by chemical oxidative polymerization of aniline in the PS latex media in a presence of lauryl sulfuric acid (LSA), which served as both dopant and plasticizer. The real content of PANI in the synthesized nanocomposites was determined by UV-Vis spectroscopy method. The composition of the nanocomposites and oxidation state of the doped polyaniline were characterized by FTIR spectroscopy. The core-shell morphology of the nanocomposite nanoparticles was proved by transmission and scanning electron microscopy. It was found that conductivity and thermal behavior in air of these nanocomposites not only nonlinearly depended on the doped polyaniline content but also were strongly effected both by plasticizing properties of the acid-dopant and presence of the polyaniline shell. A possibility of application of these nanocomposites as sensor materials has been demonstrated.

Multifunctional Role of Nanostructured CdS Interfacial Layers in Hybrid Solar Cells.

We demonstrate here a multifunctional application of CdS layers with nanotextured and nanowire morphology in four types of hybrid solar cells, i.e., (i) nanocrystal-polymer cell, (ii) nanocrystal-organic donor-acceptor bulk heterojunction (BHJ) inverted cell, (iii) nanocrystal-dye sensitized solid state cell and (iv) nanocrystal-dye sensitized electrochemical cell. The role of CdS layer in each type of the above cells has been elucidated and the photovoltaic (PV) performance of the PV cells has been compared. It is shown that CdS acts as acceptor in the cells of types (i) and (iii), while it plays the role of an electron-selective (hole-blocking) layer to direct electrons from the organic counterpart to anode in the cases (ii) and (iv). Morphology of the CdS layer makes a noticeable effect on the PV performance. In particular, the nanowire array demonstrated an improved efficiency of collection of charge carriers as compared with the continuous textured surface due to the increased organic-CdS interface area in PV cells of practically all types. It is demonstrated that the same nanocrystal-dye structure can operate either as PV cell of type (iii) or PV cell of type (iv).

New aspects of the low-concentrated aniline polymerization in the solution and in SiC nanocrystals dispersion.

Results of the simultaneous in-situ UV-vis and open-circuit potential (OCP) monitoring of the low-concentrated aniline (An) polymerization in the presence of camphorsulfonic acid (CSA) suggested that during the induction period (IP) step a transition state formed, which probably included anilinium cation and the oxidant anion, antecedent to a propagation step. No aniline oligomers were registered at this stage but they appeared at the beginning of the propagation step under the investigation conditions. The moments of formation of insoluble pernigraniline phase and appearance of emeraldine units in the growing pernigraniline chains were ascertained by the comparison of kinetic and OCP profiles of the polymerization process both in the solution and in SiC dispersion water mediums. It is deduced that pernigraniline reduction by aniline molecules begins earlier than it is generally accepted (i.e., earlier than OCP maximum is reached) and probably in parallel to a continuing appearance of pernigraniline units even in the same chains that undergo the reduction. It was found that an addition of the SiC dispersion phase into the polymerization mixture accelerates differently all stages of the aniline polymerization. Finally, this polymerization process leads to the formation of polyaniline (PANI)-CSA shell with thickness in the range from 0.5 nm to a few nm at the SiC nanocrystals surface.

[The mechanism of the radioprotective action of sulfolane]. / Mekhanizm radioprotektornogo deistviia sul'folana.

As a result of radiolysis of sulfolane, that has a radioprotective action, sulfonyl anion-radicals and hydrosulfonyl radicals are produced, subsequent transformations of which lead to complete regeneration of sulfolane. On the other hand, some other five-membered cyclic sulfones, that have no radioprotective action, are irreversibly depleted in reactions with water radiolysis products. Sulfolane is suggested to protect from the effect of e(-)aq and H. and to be ineffective in protecting against OH. radicals.