Highly stretchable strain sensors using conductive MoS2 composited PVA-PAA-Li+ hydrogels for information interaction

Wearable sensors using conductive hydrogels have been widely used in advanced technologies such as artificial intelligence, information interaction, and medical monitoring. However, it remains a major challenge to strike a balance between mechanical properties and electrical conductivity. In this work, we propose and demonstrate a conductivity-enhanced strain sensor with molybdenum disulfide (MoS 2 ) compounded as a conductive filler in the hydrogel matrix. MoS 2 not only facilitates the molding of the dual-networked poly(vinyl alcohol) and poly(acrylic acid) but also provides a physical cross-linking point for the hydrogel matrix, which improves the mechanical properties of the hydrogel with tensile strains up to 780%. Upon further immersion in lithium chloride (LiCl) solution, the conductivity of the hydrogel sensors was significantly improved up to 3.88 S m -1 because the intercalation of Li + into MoS 2 induces the synergistic effect of ionic and electronic conductivity. The inherent -OH and -COOH groups in the network made the hydrogels also self-adhesive. This study provides a new approach for the development of advanced information-interaction devices, with potential applications extending to next-generation wearable electronics and responsive sensor technologies.