Self-Healing, Expansion-Contraction, and Shape-Memory Properties of a Preorganized Supramolecular Hydrogel through Host-Guest Interactions

Supramolecular materials cross-linked between polymer chains by noncovalent bonds have the potential to provide dynamic functions that are not produced by covalently cross-linked polymeric materials. We focused on the formation of supramolecular polymeric materials through host-guest interactions: a powerful method for the creation of nonconventional materials. We employed two different kinds of host-guest inclusion complexes of -cyclodextrin (CD) with adamantane (Ad) and ferrocene (Fc) to bind polymers together to form a supramolecular hydrogel (CD-Ad-Fc gel). The CD-Ad-Fc gel showed self-healing ability when damaged and responded to redox stimuli by expansion or contraction. Moreover, the CD-Ad-Fc gel showed a redox-responsive shape-morphing effect. We thus succeeded in deriving three functions from the introduction of two kinds of functional units into a supramolecular material.