Submitted on May 12, 2008
Accepted on July 21, 2008

A Rubberlike Stretchable Active Matrix Using Elastic Conductors

¹ Quantum-Phase Electronics Center, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
² Research Center for Advanced Carbon Materials, National Institute of Advanced Industrial Science and Technology, Tsukuba 305-8565 Japan.
³ Department of Chemistry and Biotechnology, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.; Nanospace Project, Exploratory Research for Advanced Technology–Solution Oriented Research for Science and Technology, Japan Science and Technology Agency, National Museum of Emerging Science and Innovation, 2-41 Aomi, Koto-ku, Tokyo 135-0064, Japan.; Present address: Advanced Science Institute, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
⁴ Department of Chemistry and Biotechnology, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.; Nanospace Project, Exploratory Research for Advanced Technology–Solution Oriented Research for Science and Technology, Japan Science and Technology Agency, National Museum of Emerging Science and Innovation, 2-41 Aomi, Koto-ku, Tokyo 135-0064, Japan.
⁵ Quantum-Phase Electronics Center, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.; Collaborative Institute for Nano Quantum Information Electronics (INQIE), The University of Tokyo, 4-6-1, Komaba, Meguro-ku, Tokyo 153-8505 Japan.

^* To whom correspondence should be addressed.
Takao Someya , E-mail: someya{at}ap.t.u-tokyo.ac.jp

By using an ionic liquid of 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, single-walled carbon nanotubes (SWNTs) were uniformly dispersed as chemically stable dopants in a vinylidene fluoride-hexafluoropropylene copolymer matrix to form a composite film. We found that the SWNT content can be increased up to 20 weight percent without reducing the mechanical flexibility or softness of the copolymer. The SWNT composite film was coated with dimethyl-siloxane-based rubber, which exhibited a conductivity of 57 S/cm and stretchability of 134 percent. Further, the elastic conductor was integrated with printed organic transistors to fabricate a rubber-like active matrix with an effective area of 20 x 20 square centimeters. The active matrix sheet can be uniaxially and biaxially stretched by 70 percent without mechanical or electrical damage. The elastic conductor allows for the construction of electronic integrated circuits, which can be mounted on any place, including arbitrary curved surfaces and movable parts such as the joints of a robot’s arm.