From esoteric research in continuum mechanics to first commercial product of dielectric elastomer transducers (1956-2011)

I’ve just come back from EuroEAP 2011, the First International Conference on Electromechanically Active Polymer (EAP) Transducers & Artificial Muscles.  The technical program was exciting.  The meeting was chaired by Federico Carpi, and took place in Pisa, Italy.  The weather was cool, and air fresh. 

Also in the air was optimism for the new technology of dielectric elastomer transducers.   The potential of soft dielectrics as a broad-ranging technology was first brought into focus by a SRI team in a paper published in Science in 2000.  The technology is based on an extremely robust electromechanical coupling.  A membrane of a dielectric elastomer is sandwiched between two compliant electrodes, such as those made of carbon grease.  When a voltage is applied between the two electrodes, one electrode becomes positively charged, and the other becomes negatively charged.  The opposite charges cause the membrane to reduce thickness and expand area.  Linear strains beyond 100% have been achieved.  Many videos of dielectric elastomer transducers are available on YouTube.

Several companies have entered to bring commercial products to the market.  In early 2004, to commercialize dielectric elastomer transducers, SRI spun off  Artificial Muscle, Inc. (AMI).  In March 2010, AMI became a subsidiary of Bayer MaterialScience LLC.  AMI has pursued a range of applications including valves, pumps, positioners, power generation, and sensors.  The current focus is haptics in consumer electronics, a need created by the proliferation of touchscreens.  The technology is called ViviTouch™.

The first consumer product will be Pulse™, an add-on for iPod touch to enhance experience of video games.  At EuroEAP2011, the device was demonstrated.  For example, when a die is rolled on the screen of an iPod touch, you can hear the sound and feel the shake that mimic the rolling of the die.  Here are some descriptions of the device online. 

The device was designed by AMI for Mophie, a California-based company.  A licensing agreement was made between Bayer and Immersion, a company for touch feedback.  The device is fabricated by ELK Corporation in Korea. 

Further Reading

For a very brief review of the field of dielectric elastomers, see F. Carpi, S. Bauer, D. De Rossi, Stretching dielectric elastomer performance.  Science 330, 1759 (2010).

Large deformation induced by voltage has long been an area of research in mechanics.  The first landmark paper was by Toupin, R.A., The elastic dielectric. J. Rational Mech. Anal. 1956, 5: 849-914.

I have just written a review of the theory of dielectric elastomers. Acta Mechanica Solidia Sinina 23, 549-578 (2010).