Effects of cellulose nanofibrils on dialdehyde carboxymethyl cellulose based dual responsive self-healing hydrogel

A self-healing hydrogel containing acylhydrazone bond and disulfide bond with pH and redox dual responses was prepared by crosslinking dialdehyde carboxymethyl cellulose (DCMC) with 3,3 '-dithiobis(propionohydrazide) (DTP). The pH, gelator concentration and oxidation degree of DCMC affected the formation of DCMC-based self-healing hydrogels seriously. Interestingly, addition of cellulose nanofibers (CNFs) improved the mechanical property of the DCMC-based self-healing hydrogel and its efficiency. When 1.0 wt% CNFs was added in hydrogel preparation, the compressive strength (1.05 MPa) of the composite hydrogel increased by 275% and its strain rose to 74.6%. The healing rate of hydrogel containing 1.0 wt% CNFs was 82.7% at 0.5 h and 89.9% at 1 h, which was much faster than that of original hydrogel (51.6% at 0.5 h and 58.5% in 1 h). DCMC-based dual responsive self-healing hydrogel showed good biocompatibility confirmed by cytotoxicity test, which is potential to implement in medial field. Graphic abstract