Flexible MXene‐Based Hydrogel Enables Wearable Human–Computer Interaction for Intelligent Underwater Communication and Sensing Rescue

Conductive hydrogels have recently attracted extensive attention in the field of smart wearable electronics. Despite the current versatility of conductive hydrogels, the balance between mechanical properties (tensile properties, strength, and toughness) and electrical properties (electrical conductivity, sensitivity, and stability) still faces great challenges. Herein, a simplified method for constructing hydrophobic association hydrogels with excellent mechanical and electrical properties is proposed. The prepared conductive hydrogels exhibit high tensile properties (≈1224%), high linearity in the whole‐strain–range (R2 = 0.999), and a wide strain sensing range (2700%). The conductive hydrogel can realize more than 1000 cycles of sensing under 500% tensile strain. As an application demonstration, an underwater communication device is assembled in combination with polydimethylsiloxane/Triton X‐100 film coating, which successfully transmits underwater signals and provides warning of potential hazards. This study provides a new research method for developing underwater equipment with excellent mechanical properties and sensing properties. The hydrophobic associated hydrogel has excellent mechanical properties and a wide strain sensing range, and the sandwich composite sensor after packaging can be used in the underwater environment. Underwater communication can be achieved through Morse code and potential dangers can be warned, demonstrating potential applications in the field of underwater rescue.