(469i) Silicone Based Ionoelastomers for Soft, Electroactive Devices

Ionoelastomers are an emerging class of ion conducting materials wherein one of the ionic moieties of an ionic liquid is covalently attached to a polymer backbone. When two oppositely charged ionoelastomers are contacted, the interface forms an “ionic double layer” (IDL) resulting in a build-up of excess fixed charges with a capacitance of ~ 1 mF/cm². The IDL leads to asymmetric current flow when the polarity of the bias voltage is altered, analogous to the electrical rectification of a semiconductor diode. We report a class of silicone based ionoelastomers (ionosilicones) to improve electrical and mechanical performance of soft IDL devices. Thiol “click” chemistry was used to functionalize silicone backbones with imidazolium cations, sulfonylimide anions, and crosslinking sites. Under mild conditions, acrylate-functionalized ionic liquids were attached onto a silicone backbone along with pendant methacrylates, which were subsequently polymerized to form a network. The mechanical and electrical properties of these ionosilicones were characterized and compared to previously developed acrylic based ionoelastomers. As expected, ionosilicones had a significantly lower glass transition leading to higher conductivity. Efforts to improve the mechanical properties and implement into IDL devices will be discussed. Ionosilicones present a promising class of materials to take advantage of the unique electrical properties of IDL devices for electromechanical transduction and sensing.