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.