Ultra-Stretchable, Transparent Ionic Sensory Platforms for Next-Generation Wearable Artificial Skins

The primary technology of next‐generation wearable electronics pursues the development of highly deformable and stable systems. Here, nonvolatile, highly transparent, and ultrastretchable ionic conductors based on polymeric gelators [poly(methyl methacrylate‐ran‐butyl acrylate), PMMA‐r‐PBA] and ionic liquids (IL) are proposed. A crucial strategy in the molecular design of polymer gelators is copolymerization of PMMA and IL‐insoluble low glass transition temperature (T_g) polymers that can be deformed and effectively dissipate applied strains. Highly stretchable (elongation limit ≈850%), mechanically robust (elastic modulus ≈3.1 × 105 Pa), and deformation durable gels are obtained by judiciously adjusting the molecular characteristics of polymer gelators and gel composition. An extremely simple “ionic” strain sensory platform is fabricated by directly connecting the stretchable gel and a digital multimeter, exhibiting high sensitivity, stable operation, and nonvolatility. Moreover, the skin‐type strain sensor, referred to as ionoskin, is demonstrated. The gels are attached to a part of the body and various human movements are successfully monitored. The ionoskin renders the opportunity to achieve wearable ubiquitous electronics such as healthcare devices and smart textile systems.