Electronic material that’s both transparent and supple

Science News : A gelatinous material made of salty gel and rubbery tape has been developed that can conduct electricity, with potential uses in robotic, prosthetic, and electronic devices. As described by Christoph Keplinger of Harvard University and colleagues in their paper published in Science, the researchers used a 1-mm-thick piece of tape as the dielectric and a polyacrylamide hydrogel containing sodium chloride as the electrolyte. They sandwiched the tape between layers of the saltwater gel. When the researchers applied a voltage, positive charges lined up on one side of the tape and negative charges on the other. Because the opposite charges attract, they squeeze the rubbery sheet in between, forcing it to contract. By switching the voltage off and on, the sheet is made to expand and contract. Such a material could be used in soft robots and prosthetic limbs to make them more flexible. And because the vibrations caused by the material’s expansions and contractions can also generate sound, it could be used in loudspeaker systems.