Shape memory hydrogels with remodelable permanent shapes and programmable cold-induced shape recovery behavior

Most shape memory polymers apply glass transition or crystallization of domains to fix temporary shapes and shape recovery is induced by heating, which hinders their application under heat-intolerant conditions. Moreover, the permanent shapes of polymers normally cannot be altered arbitrarily after fabrication. Herein, we present a novel shape memory hydrogel with a remodelable permanent shape and programmable cold-induced shape recovery behavior. Poly(acrylic acid) (PAA) hydrogel is prepared in the presence of diethylenetriamine (DETA) and subsequently treated with calcium acetate (Ca(Ac)