Self-healing quadruple-shape memory hydrogel based on imine, coordination, and borate bonds with tunable mechanical properties

PAM/OSA/PVA hydrogel was prepared by simple copolymerization using acrylamide (PAM), oxidized sodium alginate (OSA), and poly (vinyl alcohol) as monomers. The hydrogel exhibited a quadruple-shape memory effect based on imine, coordination, and borate bonds. Self-healing properties of the quadruple-shape memory hydrogel were observed to evolve due to the imine and borate bonds. The hydrogel demonstrated tunable mechanical properties because of supramolecular interactions including OSA –Ca2+, PVA –borax, and OSA –PAM in different conditions. The new hydrogel is envisaged to increase the variety as well as broaden the design and manufacturing of shape memory hydrogels.