In work reported in Science (August 20, 2013) a Harvard MRSEC team led by Suo and Whitesides developed a transparent "ionic skin," a sensor skin using ionic conductors. It senses signals with high stability and wide dynamic range, from a gentle touch of a finger to strains over 500%. The new ionic skin has attributes required for biocompatibility in medical devices and transparency for use in tunable optics.
- As a demonstration, the electrodes were tin-plated copper, the ionic conductors were a salt-containing hydrogel, and the dielectric was an acrylic elastomer (VHB). VHB was also used to cover the faces of the ionic skin.
- The ionic skin was attached to a straight finger.
- When the finger bent, the ionic skin stretched.
- As the finger bent cyclically, the capacitance changed accordingly. 'B' denotes bent finger, and 'S' denotes straight finger.
- The ionic skin was transparent. The scale bars in b, c, e are 2 cm.
David A. Weitz (Physics & Applied Physics)
Harvard MRSEC (DMR-1420570)