Ultra‐Stretchable, Adhesive, and Anti‐Swelling Ionogel Based on Fluorine‐Rich Ionic Liquid for Underwater Reliable Sensor

Abstract Creating flexible materials that can work underwater has the potential to broaden applications to aquatic and marine environments. Hydrogels have long been thought to be excellent ionic conductors for wearable electronics, because of their high stretchability, transparency, and excellent ionic conductivity. However, due to the huge differences between the underwater and air environments, the previously reported soft materials can rarely satisfy the critical needs of adhesive, underwater stability, and steady conductivity. Herein, an ionogel is proposed with abundant physical and chemical cross‐linked, involving ion‐dipole, electrostatic, and hydrogen bonding interactions, to achieve excellent mechanical strength, resilience, and underwater stability. The ionogel with long‐lasting underwater adherence and durability is further assembled into a high sensitivity, fast response, and excellent durability underwater wearable sensor. The ionogel sensor demonstrated high precision in various human motion detection and Morse code is used to transmit information both in the air and underwater. In addition, the tough underwater adhesion and the distinct discrepancy in electrical properties in different concentration solutions enable the ionogel sensor to adhere to the surface of marine animals and monitor the water quality in their habitats. It is identified that the designed ionogel possesses great promise in wearable devices and soft ionotronics.