Soft ionic diodes formed at the interface of ionic liquid networks

Soft elastic materials capable of conducting ionic charge carriers offer numerous opportunities for the design of new classes of highly deformable electronic devices. Our group has recently studied the formation of ionic ‘diodes’ at the interface between two single-ion conducting elastomers with oppositely signed charge carriers formed by polymerization and crosslinking of ionic liquid monomers. We characterize the properties of these interfaces using a variety of techniques, in particular AC impedance spectroscopy, and show that they act as stretchable rectifying junctions based on capacitive, rather than electrochemical, effects. Further, such soft ionic diodes possess a number of potentially useful characteristics, including strain sensitive electrical signals and reversibly switchable electro-adhesion. Finally, we have explored templating methods to generate high surface area ionic diodes, which are expected to yield further improvements in properties.