Water activated ionic conduction in cross-linked polyelectrolytes

The electrical properties of polyelectrolytes depend on the water concentration of the environment. The behaviour of both conductance and capacitance caused by variations in relative humidity and temperature was investigated by impedance spectroscopy for humidity sensors based on an interpenetrated network of a polymer and a polyelectrolyte. The results were interpreted on the base of the Langmuir and Kelvin equations and two different sensing mechanisms were highlighted for low and high water content

"Solid state charge trapping": Examples of polymer systems showing memory effect

The paper reports on a characteristic property of electroactive materials bearing an electron-rich and an electron-poor moiety, known as charge trapping. As examples of materials that exhibit this phenomenon, films of poly(4,4"-dipentoxy-4\u27-(2,2\u27-dicyano)ethenyl-2,2\u27:5\u27,2"-terthiophene), poly(2,3-dihexylthieno[3,4-b]pyrazine) and a blend between a fulleropyrrolidine derivative and poly(3-hexylthiophene) were investigated by cyclic voltammetry, spectroelectrochemistry and electrochemical quartz crystal microbalance. In the cyclic voltammetry, the reduction processes show the reverse oxidation potential about 1 V higher than the expected value, indicating a strong stabilization of the corresponding anion species. The mechanism leading to the stabilisation of the anions is discussed and the results indicate that the investigated materials exhibit a remarkable and quite stable memory effect

A solid-state electrochromic device based on complementary polypyrrole polythiophene derivatives and an elastomeric electrolyte

A device was assembled using optically transparent glass electrodes and combining two complementary electrochromic polymeric materials, poly(4,4'-dipentoxy-2,2'-bithiophene) and poly(N,N'-dimethyl-2,2'-bipyrrole). As electrolyte we used an ionically conductive polymer; poly(epichlorohydrin-co-ethylene oxide) containing a lithium salt. The optical contrast in the visible/near infrared region, stability to repeated redox cycles and electrochromic efficiency are reported and discussed.29675375

An all-plastic and flexible electrochromic device based on elastomeric blends

Communication: All-plastic and flexible electrochromic devices will facilitate new technological applications, such as information display and storage, in the automotive industry (rear-view mirrors) and in architecture (smart windows). Here the authors describe an all-plastic and flexible solid-state electrochromic device using two optically complementary conductive polymer blends deposited on ITO-PET (indium tin oxide-poly(ethyleneterephthalate)), and a polymeric electrolyte. The device was constructed under atmospheric conditions and showed good optical characteristics.10181522

Properties of a Fullerene-Azothiophene Dyad as the Active Layer in Solar Cells

The cycloaddition of azomethine ylides has been used to covalently link the thienylazobenzeneamine 2 to [60]fullerene. When the resulting donor-acceptor dyad 1, with an enhanced absorption in the Vis region, was used as the active layer of a photovoltaic cell, a power conversion efficiency of 0.16% was obtained, under 80 mW cm-2 white light illumination

A Donor-Acceptor Polymer with peculiar negative-charge-“trapping” characteristic

Voltammetric and spectrophotometric measurements of poly(3,3″-dipentoxy-3′-dicyanoethenyl-2,2′:5′,2″-terthiophene) (polyCN) films, in connection with other experimental evidence, reveal a normal oxidative, but a peculiar reductive behavior consisting of trapping of the negative charge during the cathodic scan. Another interesting property of polyCN films is the tendency to form strong intramolecular and intermolecular associations, probably charge-transfer (CT) complexes. These properties could account for the fact that the photovoltaic performance does not improve when polyCN is blended with a polythiophene donor

A New Configuration Of The Solid-state Battery: Magnesium|polymer Proton Conductor|gold, Based On The Use Of Poly(o-methoxyaniline)

A solid-state battery was constructed by interfacing a pressed pellet of poly(o-methoxyaniline), in the emeraldine form with p-toluene sulfonic acid as doping agent, to a magnesium electrode covered with a film of magnesium perchlorate; the contact on the poly(o-methoxyaniline) was done by means of a gold electrode. The so-obtained cell, Mg|magnesium perchlorate|poly(o-methoxyaniline)|gold, was able to supply energy with a power depending on discharge current and on environmental humidity. Values of power up to 2.5 mW cm-2 at discharge currents of about 2 mA cm-2 were reached. © 1997 Elsevier Science S.A.9013136Gemeay, A.H., Nishiyama, H., Kuwabata, S., Yoneyama, H., (1995) J. Electrochem. Soc., 142, p. 4190Momma, T., Kakuda, S., Yarimizu, H., Osaka, T., (1995) J. Electrochem. Soc., 142, p. 1766Tsutsumi, H., Fukuzawa, S., Ishikawa, M., Morita, M., Matsuda, Y., (1995) J. Electrochem. Soc., 142, pp. L168Morita, M., Miyazaki, S., Ishikawa, M., Matsuda, Y., Tajima, H., Adachi, K., Anan, F., (1995) J. Power Sources, 54, p. 214Barbero, C., Miras, M.C., Schnyder, B., Haas, O., Kotz, R., (1994) J. Mater. Chem., 4, p. 1775Gauthier, M., Belanger, A., Bouchard, P., Kapfer, B., Ricard, S., Vassort, G., Armand, M., Krause, L., (1995) J. Power Sources, 54, p. 163Scrosati, B., Neat, R.J., (1993) Application of Electroactive Polymers, p. 182. , B. Scrosati (ed.), Chapman and Hall, LondonBoinowitz, T., Suden, G.T., Tormin, U., Krohn, H., Beck, F., (1995) J. Power Sources, 56, p. 179Capuano, F., Casalbore-Miceli, G., Giro, G., Scrosati, B., (1994) J. Appl. Electochem., 24, p. 114Camaioni, N., Casalbore-Miceli, G., Martelli, A., Yang, M.J., (1997) J. Appl. Electrochem., 27Kumar, G., Sivashanmugam, A., Muniyandi, N., Dhawan, S.K., Trivedi, D.C., (1996) Synth. Met., 80, p. 279Gazotti W.A., Jr., De Paoli, M.-A., Synth. Met., , in pressPourbaix, M., (1966) Atlas of Electrochemical Equilibria in Aqueous Solutions, p. 101. , Pergamon Press, Oxfor