The Evolution of Underwater Microelectronic Encapsulation: An Universal Marine Wearable Hydrogel

Abstract Long‐term access to undersea information is of critical importance for undersea sensing. However, the paramount challenge in marine wearable technology lies in achieving durable and stable adhesion, coupled with biocompatibility, for devices submerged in the saline conditions of the ocean. Here, a self‐healing, seawater‐resistant hydrogel is reported that exhibits robust adhesion to diverse biotic and abiotic surfaces. Remarkably, the presented hydrogel is augmented with octopus sucker‐inspired microstructures, a feature that markedly improves its capability of organism adhesion underwater. The hydrogel exhibits robust mechanical properties in water, with over 20‐fold elongation in a fully swollen state, and a mechanical healing efficiency exceeding 90% after healing for 30 min. The hydrogel is applied toward several representative undersea scenes. Specifically, the hydrogels equipped with flexible pressure sensors are reliably affixed to fish and turtles for sensing hydraulic pressure for more than 20 days, while the hydrogels featuring a compact camera are mounted on corals and crabs for constant monitoring of surroundings. Furthermore, the hydrogel is molded into a mesh structure for integrating multiple sensors, functioning as multi‐node marine wearable platforms. The underwater hydrogel, with its broad applicability, introduces an approach to real‐time undersea monitoring and non‐invasive marine life internet construction.