Dynamic Supramolecular Hydrophobic Ionogels with Ultrafast Self-Healing for Reliable Underwater Electronics.

Abstract

Conductive ionogels integrating rapid self-healing, underwater stability, and reliable sensing capability are highly desirable for next-generation wearable electronics, yet remain challenging to achieve simultaneously. Herein, a multifunctional hydrophobic ionogel is developed through in situ UV-initiated copolymerization of tert-butyl acrylate (tBA), 2-(dimethylamino)ethyl methacrylate (DMAEMA), and di(ethylene glycol) ethyl ether acrylate (DEEA) in the hydrophobic ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([EMIm][TFSI]). Strong ion-dipole interactions and hydrogen bonding between DMAEMA segments and TFSI- anions establish a dynamic supramolecular network, endowing the ionogel with ultrafast self-healing, excellent environmental tolerance, and robust adhesion in both air and underwater environments. The optimized ionogel exhibits high transparency (>96%), stable ionic conductivity (1.17 mS cm-1), excellent flexibility, and high hydrophobicity with a water contact angle of 116°. Notably, the ionogel achieves rapid self-healing with efficiencies of 98% within 30 s in air and 95% within 5 min underwater without external stimulation, while its sensing and conductive performances are almost fully restored after repeated damage-healing cycles. Benefiting from stable ion transport channels and a robust dynamic network, the ionogel-based sensor displays high sensitivity, rapid response, excellent cycling durability, and reliable underwater sensing capability. As a proof of concept, the ionogel sensor is further employed for underwater Morse-code communication and can be integrated with an Arduino-based Internet of Things (IoT) platform to demonstrate a wearable emergency alarm system operable in both air and underwater environments. This work provides a versatile strategy for developing next-generation self-healing ionogels for wearable electronics, underwater communication, intelligent sensing, and emergency rescue systems.