Stress‐Tunable Multi‐Functional Sensing Gel Fiber via Water‐Controlled Design for High Stability

ABSTRACT The development of fiber sensors faces challenges such as limited functionality and susceptibility to strain interference, making it essential to achieve multifunctionality and performance stability. Herein, a multifunctional temperature, humidity, and strain (THS) fiber sensor is designed based on an “island–bridge” structure. Unlike traditional “island–bridge” structures using heterogeneous materials, this work forms the islands and bridges regions by regulating water content within one gel matrix, ensuring strong interfacial bonding and structural stability. Temperature and humidity sensing units are built in the “island” region, enabling strain‐insensitive localized sensing. Meanwhile, the strain‐sensing unit is constructed in the “bridge” region, ensuring high flexibility. By integrating the THS fiber with soft robotic fingers, an intelligent soft gripper is developed. Assisted by a neural network, the gripper accurately identifies objects. Additionally, it performs underwater grasping tasks while sensing water temperature and detecting proximity to the water surface. Furthermore, by weaving the THS fiber into clothing, an early health risk warning system is established, enabling real‐time monitoring of respiratory rate, body temperature, and skin humidity. These advancements demonstrate the THS fiber's significant potential in environmental and human health monitoring, highlighting its broad application in wearable devices and smart clothes.