Ultra-Stretchable and Tough Organo-Hydrogel for Wearable Strain and Temperature Sensors

Hydrogels, as a representative substrate for flexible sensors, often exhibit compromised mechanical strength and environmental instability owing to insufficient molecular chain interactions. To address such grand challenges, we propose a strategy here for fabricating highly entangled MXene (2D transition metal carbides)-polyacrylamide organic hydrogel (HTO-MPM), which shows excellent extensibility and toughness. Due to the sliding properties of highly entangled polymer long chains and the low friction sliding between chains, the hydrogels show excellent strength, toughness, and low hysteresis. Moreover, MXene acts as physical crosslinking points in the entangled hydrogel, enabling polymer chains to further slide along the stretching direction. Meanwhile, its mechanical strength and water retention are strengthened by forming strong hydrogen bonds. The HTO-MPM achieves low hysteresis (<6%), high stretchability (>1700%). Thus, the hydrogel sensors maintain stable performance over 5,000 strain cycles. These combined properties render the conductive gel a promising candidate for flexible sensing components in wearable device applications.