Incorporation of multi-dynamic interactions into carboxyl graphene oxide-enhanced PVA/PAA/agarose hydrogels for multifunctional wearable sensors.

Recent advancements in conductive hydrogels have demonstrated significant progress in flexible sensing applications. However, integrating multifunctionality-including mechanical properties, environmental stability, high sensitivity, and great self-healing capability-into hydrogel sensors via a simple and eco-friendly synthesis approach remains a challenge. Herein, we reported multifunctional polyvinyl alcohol (PVA)/polyacrylic acid (PAA)/agarose (AG) hydrogels fabricated through a facile one-pot strategy. The dual-crosslinked network, enabled by AlCl₃ (physical crosslinker) and sodium tetraborate decahydrate (chemical crosslinker), synergistically enhanced structural integrity. Incorporation of carboxyl graphene oxide (GO-COOH) optimized mechanical strength (the fracture stress of 122.3 kPa) and electrical conductivity (10.56 ± 0.63 S/m). The hydrogel strain sensor exhibited exceptional sensitivity (gauge factor = 11.31 within 400-550 % strain), enabling precise monitoring of both large-scale motions (e.g., joint flexion) and subtle movements (e.g., facial expression). Notably, GO-COOH endowed the hydrogel with a rapid photothermal response, expanding its utility to photothermal sensing. Moreover, the dynamic borate ester bonds, metal coordination bonds and hydrogen bond interactions conferred 100 % self-healing efficiency, significantly prolonging the operational lifespan of the hydrogel sensor. This work presents a scalable, green synthesis route for multifunctional hydrogels, demonstrating broad potential in wearable health monitoring, environmental sensing, and human-machine interfaces.