Self-healing nanocomposite hydrogels based on modified cellulose nanocrystals by surface-initiated photoinduced electron transfer ATRP

Self-healing hydrogels with excellent toughness and mechanical strength are particularly desirable for practical application. In this paper, green and environmentally friendly cellulose nanocrystals (CNCs) were successfully modified on the surface via metal-free photoinduced electron transfer atom transfer radical polymerization (PET-ATRP). Surface-initiated PET-ATRP was achieved by using 4-vinylpyridine (4VP) as functional monomer, 10-phenylphenothiazine (Ph-PTZ) as photocatalyst and ultraviolet light (365 nm) as light source, respectively. The prepared P4VP-CNCs hybrid materials (CNCs@P4VP) were used as green reinforcement to obtain self-healing nanocomposite hydrogels by electrostatic interactions. As a result, the nanocomposite hydrogels displayed outstanding mechanical (6.6 MPa at a strain of 921.6%) and self-healing (85.9% after repairing 6 h) properties. This work provides a promising green method for designing novel self-healing nanocomposite hydrogels with high strength. Graphical abstract