Multifunctional PAA/PHEA-Based Transparent Conductive Hydrogel Reinforced by TWS-Tanned Sheepskin Collagen Fiber Skeleton as Multimodal Wearable Flexible Sensors

Conductive hydrogels possess great promise as sensing materials for flexible electronic skins; however, their practical application is often hindered by inadequate mechanical robustness, unsatisfactory environmental stability, and constrained multifunctional integration. Herein, we developed a multifunctional transparent conductive hydrogel (called LAHMP) by utilizing a sheepskin collagen fiber skeleton tanned by a commercial tanning agent (called TWS) as a mechanically robust scaffold, combined with in situ copolymerization of acrylic acid (AA) and 2-hydroxyethyl acrylate (HEA). A 1,3-propanediol/water binary solvent system was employed to establish a compact hydrogen-bonding network, which significantly enhances the hydrogel’s antifreezing performance, moisture retention, and long-term structural stability under ambient conditions. Furthermore, the incorporation of MgCl2 not only boosted ionic conductivity but also strengthened the cross-linking density through metal coordination interactions. The resulting LAHMP conductive hydrogel demonstrated exceptional physical properties, with 3.83 MPa of breaking strength, 136% of breaking elongation, and 2.37 MJ/m3 of toughness, along with high optical transparency (70% transmittance at 550 nm), excellent electrical conductivity (2.84 S/m), and considerable antibacterial activity. Importantly, the LAHMP-based wearable sensor exhibited high sensitivity in both strain and pressure sensing, which could accurately capture both large-range human movements and weak physiological changes, including facial expressions and respiration. It further enabled real-time acquisition of bioelectrical signals such as electrocardiogram and electromyogram, and supported intelligent applications such as handwriting recognition and Morse code signal transmission. This study presents a versatile, high-performance conductive hydrogel strengthened by a collagen fiber skeleton, which exhibits promising application prospects in wearable sensing, continuous monitoring of human health, and assistive communication technologies.