Photoelectrochemical Response In Conducting Polymer Films

The photoelectrochemical responses of electrochemically prepared polyaniline, polypyrrole and poly(3-methylthiophene) polymer films were studied. For polyaniline, the behavior of the photocurrent was analyzed with respect to the nature and concentration of the electrolyte solution, wavelength of the incident light and type of working electrode. Polyaninile shows a cathodic photocurrent in the reduced state and an anodic photocurrent in the oxidized state, indicating a transition from p-type to n-type semiconductor behavior. Chemically prepared polyaniline deposited by solution evaporation onto a gold substrate and covered with an aluminum layer shows a photocurrent comparable to a commercial photodiode. Polypyrrole and poly(3-methylthiophene) show characteristic cathodic photocurrent responses in the reduced state when irradiated with pulsed light, indicating a p-type semiconductor behavior. © 1994.6819196Skotheim, Lundström, Prejza, (1981) J. Electrochem. Soc., 16, p. 1626Frank, Honda, (1982) J. Phys. Chem., 86, p. 1933Noufi, Nozik, White, Warren, Enhanced Stability of Photoelectrodes with Electrogenerated Polyaniline Films (1982) Journal of The Electrochemical Society, 129, p. 2261Heeger, Kivelson, Schrieffer, Su, (1988) Rev. Mod. Phys., 60, p. 781Bleier, (1989) Electronic Properties of Conjugated Polymer Systems III Springer Series in Solid State Sciences, p. 80. , Springer, BerlinKaneko, Nakamura, (1985) J. Chem. Soc., Chem. Commun., p. 34Geniès, Łapkowski, Influence of light on the electrochemical behaviour of polyaniline films (1988) Synthetic Metals, 24, p. 69Shen, Tian, Photoelectrochemical behavior of polyaniline in the presence of redox couple and electron acceptor (1989) Electrochimica Acta, 11, p. 1611Kalaji, Nyholm, Peter, Rudge, (1991) J. Electroanal. Chem., 310, p. 113Desilvestro, Haas, (1991) Electrochim. Acta, 36, p. 361Wan, (1992) Chin. J. Polym. Sci., 10, p. 8Geniès, Łapkowski, Noel, Langlois, Collomb, Miquelino, Recent results on polyanilines, electrochemistry, EPR substituted derivatives, applications, displays, etc… (1991) Synthetic Metals, 41-43, p. 2847Inoue, Yamase, (1983) Bull. Chem. Soc. Jpn., 56, p. 985Deronzier, Essakali, (1991) J. Phys. Chem., 95, p. 1737Glens, Tourillon, Garnier, (1984) Thin Solid Films, 122, p. 9Kaneto, Ishii, Yoshino, Photoelectrochemical Cell Using Polythiophene Film (1985) Japanese Journal of Applied Physics, 24, p. L320Shiraishi, Kaneto, Yoshino, (1986) Technol. Rep. Osaka Univ., 36, p. 329Peramunage, Tomkievicz, Ginley, (1987) J. Electrochem. Soc., 134, p. 1384Youm, Cadene, Laplaze, Lincot, Vedel, (1992) J. Chim. Phys., 89, p. 1105Youm, Cadene, Laplaze, (1992) J. Chim. Phys., 89, p. 1111Kankare, Vuorinen, Alanko, Lukkari, Characterization of the first steps in electropolymerization by photocurrent spectroscopy (1993) Journal of the Chemical Society, Chemical Communications, p. 241Fang, Chen, Chu, (1992) Synth. Met., 52, p. 261Peres, Pernaut, De Paoli, Properties of poly(pyrrole) films electrochemically synthesized in the presence of surfactants (1989) Synthetic Metals, 28, p. C59Geniès, Boyle, Łapkowski, Tsintavis, Polyaniline: A historical survey (1990) Synthetic Metals, 36, p. 139Gerischer, (1990) Electrochim. Acta, 35, p. 1677Stolka, Pai, Polymers with photoconductive properties (1978) Adv. Polym. Sci., 29, p. 1Geniès, Łapkowski, Evidence of two kinds of spin in polyaniline from in situ EPR and electrochemistry (1990) Journal of Electroanalytical Chemistry and Interfacial Electrochemistry, 279, p. 157Cox, (1989) The Electronic Structure and Chemistry of Solids, pp. 235-240. , Oxford University Press, Londo

Efeito das condições de preparação na condutividade elétrica de blendas de poli(fluoreto de vinilideno) e poli(o-metoxianilina) Effect of preparation conditions on the electrical conductivity of blends of poly (vinylidene fluoride) and poly(o-methoxyaniline)

Neste trabalho estudou-se o efeito das condições de preparação na condutividade elétrica de blendas condutoras de poli(fluoreto de vinilideno) (PVDF) com poli(o-metoxianilina) (POMA). A condutividade elétrica e a qualidade dos filmes produzidos dependem significativamente do solvente, dopante e das condições de preparação das blendas. Filmes flexíveis e auto-sustentáveis da blenda PVDF/POMA dopada com o ácido p-tolueno sulfônico (TSA) foram obtidos em condições otimizadas. Estes apresentam condutividade elétrica em uma larga faixa (10-12 - 10-2 S/cm), onde para baixos teores de POMA-TSA (<2,0% em massa) já se atinge alto valor de condutividade (10-7 S/cm), não sendo definida uma composição mínima para percolação.<br>In this work, the effect of preparation conditions on the properties of conductive blends of poly (vinylidene fluoride) (PVDF) and poly(o-methoxyaniline) (POMA) was studied. The quality and conductivity of the films produced depend significantly on the solvent, dopant and preparation conditions of the blends. Flexible, free-standing films of PVDF/POMA blends doped with p-toluene sulfonic acid (TSA) were obtained in optimized conditions. These blends can exhibit electrical conductivity in a wide range (10-12 - 10-2 S/cm). Furthermore, relatively high conductivity values (10-7 S/cm) are reached starting from low contents of POMA-TSA (<2,0% weight) without definition of a percolation threshold

Polymer nanocomposites for multifunctional finishing of textiles: a review

Improvement of existing properties and the creation of new material properties are the most important reasons for the functionalization of textiles. Polymer nanocomposites offer the possibility of developing a new class of nanofinishing materials for textiles with their own manifold of structure property relationship only indirectly related to their components and their micron and macro-scale composite counterparts. Though polymer nanocomposites with inorganic filler of different dimensionality and chemistry are possible, efforts have only begun to uncover the wealth of possibilities of these new materials. Approaches to modify the polymer nanocomposite system by various inorganic or organic substances can lead to a huge number of additional functionalities which are increasingly demanded by the textile industries. In this review, we have compiled the current research in polymer nanocomposite-based nanofinishes for multifunctional textiles which provides a snapshot of the current experimental and theoretical tools being used to advance our understanding of polymer nanocomposites and their applications in textiles.Sorna Gowri is grateful to Fundacao para a Ciencia e a Tecnologia (FCT), Portugal, for supporting this study through a Post Doctoral Fellowship