Multi-Network Poly(β-cyclodextrin)/PVA/Gelatin/Carbon Nanotubes Composite Hydrogels Constructed by Multiple Dynamic Crosslinking as Flexible Electronic Devices

Multifunctional hydrogels with good stretchability and self-healing properties have attracted considerable attention in the field of flexible electronic devices. However, hydrogels constructed by traditional chemical crosslinking usually have poor mechanical properties and lack self-healing, adhesion, and biocompatibility, which cannot meet the requirements of flexible wearable devices. This work introduced multiple dynamic crosslinking, including borate ester bond, Schiff-base, and host-guest interaction, into polymer networks to fabricate triple-network gelatin/polyvinyl alcohol/carbon nanotube composite hydrogels with good self-healing ability (healing efficiency of 95.0%), mechanical strength (54.6 kPa), stretchability (778%), biocompatibility, conductivity, adhesion, and remodeling properties. Carbon nanotubes can serve as the filler to improve the electrical conductivity of the triple-network hydrogels. The resulting hydrogel can be made into a strain sensor with high strain sensitivity (gauge factor up to 16.0). More importantly, the strain sensor can be used to monitor various human and organ movements. Owing to its good self-healing ability, the self-healed hydrogel sensor also can detect human movements with almost the same electrical signal strength as the original one. This study gives novel insights for the design of multifunctional self-healing hydrogels that have great potential in various application fields such as electronic skins, soft robots, and wearable devices.

Automated summary

This study introduced multiple dynamic crosslinking strategies to construct a triple-network hydrogel with excellent properties, including good self-healing ability, mechanical strength, stretchability, biocompatibility, conductivity, adhesion, and remodeling capabilities. The resulting hydrogel can be made into a high sensitivity strain sensor and has the ability to monitor human movements.