Superelastic and highly sensitive conductive hydrogel sensor enabled by spatially confined assembly of MXene within...

Conductive hydrogels have garnered significant attention in the field of flexible wearable sensors due to their intrinsic conductivity and tunable mechanical properties. However, simultaneously achieving both high mechanical stability and high sensing sensitivity remains a significant challenge. In this study, a conductive hydrogel with a low-hysteresis interpenetrating polymer network structure was fabricated via one-pot free-radical polymerization. The three-dimensional network of bacterial cellulose (BC) provides mechanical support for MXene, forming the first network layer of the hydrogel via hydrogen bonding. The second network is constructed by in situ polymerization of acrylamide (AM) within the BC framework. The incorporation of BC significantly improves both mechanical strength and electrical conductivity, effectively overcoming the typical trade-off among strength, toughness, and conductivity observed in conventional conductive hydrogels. As a result, the optimized hydrogel exhibits exceptional stretchability (elongation at break ~1800%), high toughness, excellent resilience, and high conductivity (435.6 mS m^-1), along with a rapid response time of 400 ms. Moreover, the hydrogel demonstrates high sensing sensitivity (GF = 11.48 at 600-800% strain) and long-term signal stability, enabling its application in flexible wearable sensors for accurate detection of human motion and voice signals. These properties highlight the hydrogel's broad potential for use in human-machine interface technologies.