Development and Application Research of Self-Healing/Self-Adhesive Conductive MXene Hydrogels

This study employs polyvinyl alcohol borax hydrogels as a substrate. By incorporating tannic acid-modified cellulose nanocrystals (TA@CNC) and applying freeze-thaw cycles, the hydrogels acquire self-adhesive properties and enhanced mechanical performance. Concurrently, the addition of MXene and Al³⁺, coupled with reduced freeze-thaw duration, significantly improves the hydrogels' extensibility and strain-sensing capabilities. The prepared hydrogel exhibits macroscopically reparable damage through the cleavage and reformation of borate bonds. Increasing the TA@CNC content from 0 wt% to 0.4 wt% resulted in tensile strength increasing from 13.5 kPa to 33.3 kPa, elongation at break rising from 1350% to over 2000%, maximum adhesion to aluminium reaching 16.2 kPa, and a 60-second self-healing efficiency of 99.4%. MXene primarily imparts excellent electrical conductivity to the hydrogel due to its unique functional groups exhibiting good dispersion in water. With the incorporation of Al³⁺, the self-healing efficiency of the hydrogel after 24 hours increased from 73.9% to 87.3%. The recovery rate of the cyclic tensile curve under 200% strain reached 91.1%, demonstrating excellent resilience and fatigue resistance. This enables the conductive hydrogel not only to convert large strains into regular electrical signal curves but also to detect minute strains.