A tough and Highly Sensitive Liquid Metal-Reduced Graphene Oxide Composite Hydrogel with Strain and Photothermal Response Performance

With the rapid advancement of artificial intelligence, flexible wearable sensors based on conductive hydrogels have gained significant attention. However, conventional hydrogels often use toxic cross-linkers to achieve desirable tensile strength by forming a three-dimensional network structure. This impedes their potential applications in wearable sensors. In this study, we present an approach to construct a purely physically cross-linked liquid metal-reduced graphene oxide (GO) composite hydrogel, entirely free from toxic cross-linkers. The results show that this hydrogel has outstanding stretchable properties (strain: 348.22%, stress: 4.239 MPa). By optimally designing the hydrogel's structure, the favorable sensitivity coefficients: optimum gauge factor = 20.2 (0–100% strain, R2 = 0.98), and wide photothermal response range (808–850 nm) were obtained. Further, the incorporation of reduced GO @ liquid metal particles (rGO@LM) enhances the photothermal response ability and strain sensing performance. This work provides a pathway for the development of conductive hydrogels with high sensitivity and multifunctional responsiveness, offering promising applications in motion detection and temperature monitoring sensors.