Cellulose nanocrystal reinforced conductive nanocomposite hydrogel with fast self-healing and self-adhesive properties for human motion sensing

Conductive composite hydrogels as artificial skin-like materials are receiving much attention because they hold great potential applications in personalized healthcare. However, to design and prepare a versatile material simultaneously possessing such multi-functions still remains a challenge. Herein, a robust, self-healing and self-adhesive conductive hydrogel was fabricated via forming dynamic coordination bonds between tannic acid-decorated cellulose nanocrystals ([email protected]), partially reduced graphene oxide (pRGO) nanosheets and polyvinyl alcohol (PVA) network. The catechol groups from tannic acid imparts the hydrogel with self-adhesive capability to various substrates. Besides, the mechanical strength and electrical conductivity of the hydrogels was well balanced by incorporation of pRGO component, endowing the hydrogel with robustness and good electrical conductivity as well as decent strain-sensitivity. Benefiting from all these advantages, the conductive nanocomposite hydrogel could be used as flexible strain sensors monitoring both large (e.g., joints bending) and subtle (e.g., voice detection) human motion, in real-time. The currently reported hydrogel design gives a new perspective for the preparation of high-performance cellulose-based hydrogels that hold great potential for practical applications in wearable electronic sensors and healthcare monitoring.