Takeo Shimidzu

Charge-controllable polypyrrole/polyelectrolyte composite membranes: Part II. Effect of incorporated anion size on the electrochemical oxidation-reduction process

Abstract Polypyrrole (PPy) films with various electrolyte anions were prepared by electropolymerization of pyrrole (py)in water. While the anodic doping process in the electropolymerization of py was scarcely affected by the size of the electrolyte anion, the oxidation-reduction (doping-undoping) process in the resulting PPy was influenced largely by the size of the incorporated anion (the dopant anion). Especially, an anionic polyelectrolyte (PE, an immobilized polymer dopant) incorporated in PPy was not released from the PPy matrix even when PPy was reduced electrochemically. The electroneutrality of PPy/PE (PE-incorporated PPy) was conserved by penetration of the electrolyte cation into the PPy matrix (pseudo-cathodic doping). The fixed charge polarity in PPy/PE was inverted reversibly between the positive and negative sign through the oxidation and the reduction of PPy. The PPy/PE composite acted as a “charge-controllable membrane”.

Charge-controllable poly pyrrole/poly electrolyte composite membranes: Part III. Electrochemical deionization system constructed by anion-exchangeable and cation-exchangeable polypyrrole electrodes

Abstract Chloride anion incorporated polypyrrole (PPy/Cl−) and poly(vinylsulfate) incorporated PPy (PPy/PVS−) electrodes were prepared by electrochemical polymerization of pyrrole in water. The PPy/Cl− and the PPy/PVS− had anion-exchange and cation-exchange abilities, respectively. Combination of these two PPy electrodes enabled electrochemical deionization from KCl aqueous solution and regeneration of the native PPy electrodes electrochemically. An efficient deionization was achieved without either decomposition of water on the PPy electrodes or self-discharge of the PPy. Concentrations of 10−3 mol 1−1 and 10−4 mol 1−1 KCl aqueous solutions were decreased to less than 10−4 mol 1−1 and 10−5 mol 1−1, respectively, by galvanostatic electrolysis with the PPy electrodes.

A novel type of polymer battery using a polypyrrole–polyanion composite anode

Polypyrrole incorporating an anionic polymer dopant was used as the anode of a polymer battery utilizing its pseudo-cathodic doping process.

Synthesis of novel porphyrin arrays directly-linked through the meso-carbons

Abstract Novel dimeric and trimeric arrays of free-base porphyrins directly-linked through their meso -carbons without any spacer were synthesized and characterized. The significant spectral change occurred in the absorption spectra of these arrays compared with that of the reference monomer, indicating strong electronic interactions in spite of the orthogonal geometry between the adjacent porphyrins.

Syntheses of conducting polymer Langmuir-Blodgett multilayers

Abstract Three types of method for the preparation of conducting polymer Langmuir-Blodgett (LB) films with high conductive anisotropy are demonstrated. The resulting LB multilayers of polypyrrole derivatives and a polyaniline derivative exhibit anisotropic conductivity due to the alternating layered structure ofsb conducting polymer layers and insulating alkyl or perfluoroalkyl chain layers.

Approaches to conducting polymer devices with nanostructures : photoelectrochemical function of one-dimensional and two-dimensional porphyrin polymers with oligothienyl molecular wire

Abstract The nanofabrication of molecular semiconductors for the construction of molecular photoelectronic devices is an important of research; to this end, we have constructed porphyrin polymers possessing a tailor-made structure. In this paper, we report the photoelectronic function of the porphyrin polymers connected by oligothienyl bridges. One-dimensional porphyrin polymers with various lenghts of oligothienyl bridge in the axial direction were synthesized by the electrochemical polymerization of symmetrical bis(oligothienylalkoxy) phosphorus(V)-porphyrin. The conductivity of the polymer was strongly enhanced by photoirradiation, indicating photoinduced carrier formation. The layered sandwich cell of the polymer with polybithiophene showed electric rectifying properties in the dark. Interestingly, photovoltage and photo-current were observed on photoirradiation. On the basis of these results, a microscopic polymer junction chip was constructed. Two-dimensional porphyrin polymers containing oligothienyl bridges in the lateral direction were prepared by similar electrochemical oxidation of meso -tetrakis (oligothienyl) porphyrin metal complexes and were fabricated as layered diodes.

Conducting polymer electrodes with high performances through anodic doping process

Abstract A novel approach to functionalize conducting polymer electrodes is developed through anodic doping process. Every negatively-charged functional molecule is efficiently incorporated into conducting polymer matrix on electro-polymerization. The resulting conducting polymer electrodes show a wide variety of high performances responsible for the functional molecules.

A novel anisotropic conducting thin film having a conducting and insulating layered structure

Electrochemical polymerization of Langmuir-Blodgett multilayers of amphiphilic pyrrole derivatives resulted in novel anisotropic conducting thin films (T. Iyoda, M. Ando, T. Kaneko, A. Ohtani, T. Shimidzu and K. Honda, Tetrahedron Lett., 27 (1986) 5633). They have an alternating layered structure of a conducting polypyrrole layer and an insulating alkyl chain layer. This paper deals with their syntheses, characterizations and functionalities.

Electrochemical polymerization in Langmuir-Blodgett film of new amphiphilic pyrrole derivatives

Abstract Electrochemical polymerization in Langmuir-Blodgett multilayers of amphiphilic pyrrole derivatives resulted in anisotropic conducting thin films having alternate conducting and insulating layered structure.

Synthesis of axial dialkoxy phosphorus(V)porphyrin derivatives—novel hypervalent phosphorus compounds

Water-stable, axial dialkoxy hypervalent phosphorus(V)tetraphenylporphyrins have been synthesised in a novel fashion by efficient substitution of axial chloride ligands of dichlorophosphorus(V)-tetraphenylporphyrin.