Antiswelling, Ultrastretchable, and Ultrastable Hydrogel Sensors for Long‐Term Underwater Monitoring

Abstract Wearable strain sensors designed for underwater environments and monitoring users’ health status and safety are highly desirable. However, constructing antiswelling, stretchable, and stable hydrogel strain sensors for prolonged underwater monitoring is still a great challenge. In this work, conductive hydrogel sensors suitable for comprehensive environmental monitoring are developed by integrating conductive montmorillonite (MMT) into hydrogels. The conductive hydrogels demonstrate exceptional stretchability, elasticity, electrical conductivity, a wide operational range, and high sensing accuracy. Additionally, the sensors exhibit excellent underwater stability, making them suitable for use in underwater communication and alert systems. The conductive hydrogels developed herein present a novel pathway for advancing underwater sensing applications, human‐robot interaction, soft robotics, and underwater intelligent devices.