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69:112 Q. M. Zhang, Materials Research Laboratory, The Haisheng Xu, V. Bharti, Z.-Y. Cheng, Pennsylvania State University, University Park, PA 16802; Pen-Cheng Wang, A. G. MacDiarmid, Chemistry Department, University of Pennsylvania, Philadelphia, PA 19104 ABSTRACT In many device applications, such as electro-acoustic transducers and actuators based on high strain electroactive polymers, there are many advantages to utilize conductive polymers as electrodes. However, in these applications, a high electric power usually is required which translates to high voltage and high current in the system. Hence, the maximum current density which a conducting polymer can carry is of great interest and importance. In this paper, the conduction behavior at high current density of doped polyaniline(PANI) is reported. It was found that the current density deviates strongly from the ohmic relation with the electric field in high current density region and a saturation of the current density was observed. The maximum current density Jm observed is proportional to the conductivity of the samples and for PANI doped with HCSA, Jm can reach as high as 1200 A/cm2 . Making use of the conducting polymer as the electrodes for the electrostrictive P(VDF-TrFE) copolymer, an all-polymer electromechanical system was fabricated. The all-polymer films exhibit similar or larger electric field induced strain responses than those from films with gold electrodes, presumably due to reduced mechanical clamping from the electrodes. In addition, the all-polymer system also exhibits comparable dielectric and polarization properties to those of gold-electroded P(VDFTrFE) films in a wide temperature (from -50'C to 120'C) and frequency range (from 1Hz to 1MHz). These results demonstrate that polyaniline can be used for many electro-acoustic devices and provide improved performance. INTRODUCTION Recently, we reported that electron-irradiated P(VDF-TrFE) copolymers exhibit an exceptionally high electrostrictive response', which will have a great impact in transducer, sensor, and actuator technologies2 . Because of a high elastic modulus, the commonly used metal electrodes, such as Au and Al, may impose mechanical clamping on the polymer which can reduce the electric field induced strain level and the efficiency of the electromechanical transduction. In addition, at high strain level, thin metal electrodes will crack and cause failure in the devices. Hence, a new electrode material which can lower the clamping effect and withstand high strain is highly desirable. It is believed that a conducting polymer electrode will meet these requirements 3' 4. Due to the flexibility, low acoustic impedance, and elastic modulus of conductive polymer electrodes, such all-polymer electrostrictive systems may improve the performance of electromechanical polymer materials in acoustic and electromechanical applications. In many applications, a high electric power and high electric field will be delivered through polymer electrodes in electromechanical devices, and hence, the curr