Showing papers by "Alan G. MacDiarmid published in 1998"
TL;DR: In this paper, the conductivity of polypyrrole electrodes was improved by depositing conductive polymer electrodes directly on both sides of solution-cast electrostrictive polyurethane elastomer films.
Abstract: All-polymer electrostrictive soft films were developed for the first time by depositing conductive polymer (polypyrrole) directly on both sides of solution-cast electrostrictive polyurethane elastomer films. The final composite films are flexible with strong adhesion between the polyurethane film and the conductive polymer electrode. The conductivity (sheet resistivity ∼1000 Ω/□), of the polymer electrode is appropriate for its intended use. The compatible interface between the polypyrrole electrode polymer and the electrostrictive polyurethane significantly improves the acoustic and optical transparency of these composite films, compared with using a metal electrode film. The all-polymer films also exhibit comparable dielectric properties to gold-electroded polyurethane films in the temperature range from −40°C to +80°C. The temperature range covers the soft segment glass transition temperature of the polyurethane elastomers, which is about −20°C. The films also show large electric field induced strain responses which are dependent on film thickness and measurement frequency. The electrostrictive characteristics in the all-polymer films show similarities to those of the films with gold electrodes under identical measurement conditions. © 1998 John Wiley & Sons, Ltd.
59 citations
Patent•
02 Oct 1998
TL;DR: In this article, a conductive polymer is directly deposited onto opposing surfaces of a thermoplastic polymer elastomer film, which may improve the performance of electromechanical polymer materials in acoustic applications.
Abstract: The present invention generally describes all-polymer electrostrictive systems. In the systems, a conductive polymer is directly deposited onto opposing surfaces of a thermoplastic polymer elastomer film. Due to its flexibility, strong coherent interfaces and significantly improved acoustic transparency and reduced clamping effect, the all-polymer electrostrictive system may improve the performance of electromechanical polymer materials in acoustic applications.
31 citations
TL;DR: In this paper, the performance of polymer LEDs having the configuration Al/MEH-PPV/ITO was improved by light iodine p-doping of the emissive MEH- PPV polymer layer, whereby the turn-on voltage is reduced from approximately 10 V to approximately 5 V.
Abstract: Ionic species in emissive polymer: The performance of polymer LEDs having the configuration Al/MEH-PPV/ITO (where MEH-PPV equals poly(2-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylene- vinylene) have been improved by light iodine p-doping of the emissive MEH-PPV polymer layer to presumably produce (MEH- PPV) x +y (I 3 ) xy - whereby the turn-on voltage is reduced from approximately 10 V to approximately 5 V and the external quantum efficiency is increased by an order of magnitude. It differs from non-doped MEH-PPV LEDs in that light emission is observed in both forward and reverse bias modes. The presence of (MEH-PPV) x +y ions at the cathode facilitate electron injection due to (partial) compensation of the injected charge while I 3 - ions at the anode analogously facilitate injection of holes. Ionic species in non-emissive polymer: LEDs having the configuration Al/MEH-PPV/ITO, at a constant applied potential of approximately 11 V, reached maximum intensity of light- emission after approximately 0.07 minute. Those having the configuration Al/MEH-PPV/EB/ITO reached maximum intensity (at approximately 11 V) after approximately 4.2 minutes (where 'EB' equals emeraldine base, the non-doped form of polyaniline), while those having the configuration Al/MEH- PPV/EB.HCSA/ITO reached maximum intensity (at approximately 11 V) after approximately 7.2 minutes (where 'EB.HCSA' is EB completely doped by camphor sulfonic acid). In each case, decay in intensity began to occur after the maximum was reached. The behavior of both systems are consistent with a non-electrochemical model wherein the new phenomena are controlled by an electric field induced diffusion of positive and negative ions towards the appropriate electrodes.