06-04-2011, 03:56 PM
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Electroactive Polymer “Artificial Muscle” Operable in Ultra-High Hydrostatic Pressure Environment
ABSTRACT—
Transducers for high-power sonars, an important tool for undersea exploration and monitoring, may be required to work in deep water where pressures are higher than several tens of MPa.
In contrast with the piezoelectric devices commonly used as highpower sonars for seabed resource exploration, electroactive polymers offer the benefits of high coupling efficiency, low cost, and the ability to form large area skins or other devices. One question about the use of electroactive polymers for sonar has been their ability to withstand the rigors of the deep-sea environment. In arecent experiment, we have verified that the dielectric elastomer type of electroactive polymer can maintain good operational characteristics even in an ultrahigh-pressure environment by showing that the electroactive strain response to an applied voltage was unaffected by externally applied pressures of up to 100 MPa.
Index Terms—Dielectric elastomers, electroactive polymer artificial
muscle, transducer
I. BACKGROUND OF DIELECTRIC ELASTOMERS ADIELECTRIC
Elastomer actuator is formed from two flexible and elastic electrodes that sandwich an electrically insulating elastomer. When a voltage is applied across the electrodes, the elastomer is squeezed in thckness and expands in area. Dielectric elastomers have a theoretical high electromechanical coupling efficiency (80%–90%) because of its low viscoelastic loss and electrical leakage. The maximum reported specific energy density is about 21 times that of single-crystal piezoelectric and, along with the maximum strains of over 100%, are more than two orders of magnitude greater than that of most commercial actuator materials [1]. Dielectric elastomers have been shown to function well as loudspeakers and have a dynamic range of at least DC to 60 kHz [2]. The elastomers in dielectric elastomers are based upon relatively
Low-cost commercially available polymers. Thus, dielectric elastomers appear to be well-suited for sonar applications.
II. EXPERIMENTAL METHOD AND RESULTS
The electroactive polymer device used in this experiment was a thin sheet of acrylic (3M Corporation VHB 4905, 40 in Manuscript received September 13, 2009; revised February 12, 2010 and March 29, 2010; accepted May 11, 2010. Date of publication September 20, 2010; date of current version October 29, 2010. The associate editor coordinating the review of this paper and approving it for publication was Prof. Istvan Barsony. S. Chiba, R. Kornbluh, and R. Pelrine are with SRI International, Menlo Park, CA 94025 USA. M. Waki is with the Hyper Drive Corporation, Chuo-ku, Tokyo 103-0015, Japan (e-mail: waki[at]hyperdrive-web.com). T. Sawa and H. Yoshida are with the Japan Agency for Marine-Earth Science and Technology, (JAMSTEC), Kanagawa-ken, 237-0061, Japan.
Digital Object Identifier 10.1109/JSEN.2010.2053702
