Li/Al-LDH Reinforced Polyacrylamide/Xanthan Gum Semi-Interpenetrating Network Nano-Conductive Hydrogels for Stress Sensing and Wearable Device Applications.

Layered double hydroxides (LDHs) have gained significant attention for their unique physicochemical properties, but their application in conductive hydrogels for strain-sensing still remains rarely explored due to their low electrical conductivity and poor compatibility with the hydrogel network. This study proposes an innovative strategy of preparing highly conductive and mechanically robust Li/Al-LDH reinforced polyacrylamide (PAM)/xanthan gum (XG) semi-interpenetrating network nano-conductive hydrogels (PXL) by in situ polymerization of acrylamide (AM) monomers in Li/Al-LDH colloidal solution. Li/Al-LDH exhibits high electrical conductivity and meanwhile interacts with the polymer matrix to form coordination/hydrogen bonds. The unique multi-collaborative network endows the PXL hydrogel with excellent mechanical properties (the strain at break is 2350%) and high sensing properties (the gauge factor is 4.65). As a proof of concept, an 8 × 8 sensor array and an intelligent insole are designed based on the PXL hydrogel, demonstrating the great broad prospects of PXL in medical, human-computer interaction, and flexible wearable applications. This study provides new insights for introducing highly conductive and uniformly dispersed LDHs into hydrogels for flexible wearable electronics.