Graphene Enhances the Shape Memory of Poly (acrylamide-co-acrylic acid) Grafted on Graphene

Acrylamide and acrylic acid are grafted on graphene by free-radical polymerization to produce a series of graphenepoly(acrylamide-co-acrylic acid) hybrid materials with different contents of graphene. The materials demonstrate shape memory effect and self-healing ability when the content of graphene is in the range of 10%30% even though poly(acrylamide-co-acrylic acid) itself had poor shape memory ability. The permanent shape of the materials can be recovered well after 20 cycles of cut and self-healing. The result is attributed to the hardsoft design that can combine nonreversible cross-link by grafting copolymer on graphene and reversible cross-link utilizing the zipper effect of poly(acrylamide-co-acrylic acid) to form or dissociate the hydrogen-bond network stimulated by external heating.