Zinc Ion Uniquely Induced Triple Shape Memory Effect of Dipole-Dipole Reinforced Ultra-High Strength Hydrogels

In this study, we demonstrate that dipoledipole interaction can be employed to not only tremendously enhance the mechanical properties of hydrogel, but also impart the gel to an amazing ability to memorize two temporary shapes. Cross-linked hydrogels synthesized by copolymerization of acrylonitrile, a dipoledipole containing monomer and hydrophilic comonomer are shown to exhibit triple shape memory (SM) triggered by the dynamic association and dissociation of dipoledipole pairing between cynao groups uniquely responding to zinc ion species and concentration. This approach contributes to design and fabrication of novel SM hydrogels in a distinct way from conventional SM materials.