Superstretchable and multifunctional ionogel for facile fabricating flexible strain sensors

With the rapid development of "Internet of Things" and human-computer interaction techniques, it is essential and urgent to develop facile and scalable fabrication platforms for stretchable flexible sensor. Herein, we report a facile strategy of using the green choline chloride–acrylamide deep eutectic solvent (CC-AM DES) to guide the in-situ ring-opening polymerization of α-lipoic acid (LA), leading to the successful development of a stretchable ionogel material. The as-prepared ionogel from CC-AM DES system exhibits multifunctional merits including the super stretchability (>9000%), 100% UV-blocking ability, tunable adhesiveness (29–414 kPa), high ionic conductivity (4.45 × 10−4 S/cm), and ideal anti-freezing (–27°C). In addition, this outstanding ionogel can be readily coated on various material substrates with designable shapes and patterns. Owning to these promising properties and performances, a scalable flexible strain sensor is assembled from the ionogel and exhibits stable resistance variations (R/R0) towards multiple external mechanical stimulus. This study provides a green, cost effective, and scalable strategy to fabricate ionogel materials and multifunctional flexible strain sensors, showing a great potential in the fast-emerging highly stretchable wearable/flexible electronics.