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

Abstract

Supramolecular materials cross-linked between polymer chains by noncovalent bonds have the potential to providedynamic functions that are not produced by covalently cross-linked polymeric materials.Wefocused on the formation of supramolecular polymeric materials through host-guest interactions:apowerful method for the creation of nonconventional materials.W ee mployed two different kinds of host-guest inclusion complexes of b-cyclodextrin (bCD) with adamantane (Ad) and ferrocene (Fc) to bind polymers together to form as upramolecular hydrogel (bCD-Ad-Fc gel). The bCD-Ad-Fc gel showed self-healing ability when damaged and responded to redoxs timuli by expansion or contraction. Moreover,t he bCD-Ad-Fc gel showed ar edoxresponsive shape-morphing effect. We thus succeeded in deriving three functions from the introduction of two kinds of functional units into asupramolecular material.

Self‐Healing Hydrogels

“…A supramolecular hydrogel from poly ( N , N ‐dimethylacrylamide‐ r ‐glycidol methacrylate‐ β ‐cyclodextrin) and poly( N , N ‐dimethylacrylamide‐ r ‐2‐hydroxyethylmethacrylate‐ferrocene) exhibited 100% self‐recovery of the storage and loss moduli during continuous step‐strain‐relaxation ( γ = 0.1 and 100%) experiments . β ‐Cyclodextrin‐functionalized acrylamide, adamantane‐functionalized acrylamide, ferrocene‐functionalized acrylamide and poly( N ‐isopropylacrylamide)/poly(acrylamide) hydrogels also exhibited self‐healing within 2 h, at RT (20 °C) and under “wet conditions” . This hydrogel obtained 68% healing efficiency based on the restoration of the adhesion strength after 72 h of healing.…”

“…This hydrogel obtained 68% healing efficiency based on the restoration of the adhesion strength after 72 h of healing. The hydrogel exhibited redox‐responsive behavior, i.e., redox stimuli caused the uptake and release of water causing the volume to expand and contract, and resulted in shape‐memory behavior . Polyelectrolyte hydrogels based on cholesterol (Chol)‐modified triblock poly( L ‐glutamic acid)‐ block ‐poly(ethylene glycol)‐ block ‐poly(L‐glutamic acid) ((PLGA‐ b ‐PEG‐ b ‐PLGA)‐ g ‐Chol) and β ‐cyclodextrin ( β ‐CD)‐modified poly( L ‐glutamic acid) (PLGA‐ g ‐ β ‐CD) were capable of SELF .…”

Functional self-healing materials and their potential applications in biomedical engineering

“…Adapting a different strategy, a supramolecular hydrogel possessing both self-healing and shape memory was also reported via hostguest interactions (Fig. 3) [16]. One host β-cyclodextrin (βCD) and two kinds of guest moieties adamantine (Ad) and ferrocene (Fc) were immobilized to the backbone of the hydrogel, responsible for its self-healing performance.…”

Recoverable and self-healing electromagnetic wave absorbing nanocomposites

“…[13][14][15] Self-healing property, fulfilled by the reversibility of macromolecular systems, has been studied extensively under noncovalent (physical) interactions, i.e. the inherent long-chain entanglements, [16] metal-ligand coordination, [17] host-guest interactions, [18,19] ionic interactions, [20] electrostatic interactions, [21] π-π stacking, [22] and hydrogen bonds. [23] Self-healing can be obtained by generating reversible chemical covalent bonds in the materials network, [24][25][26][27] those chemical interactions include acylhydrazone bonds, [28][29][30] disulfide bonds, [31,32] boronic ester linkages, [33] diarylbibenzofuranone links, [34] thiuram disulfide units, [35] Diels-Alder reactions, [36] and imine bonds (-CH=N-).…”