Mechano-Responsive Hydrogels Driven by the Dissociation of a Host–Guest Complex

Abstract

We developed a mechano-responsive hydrogel that is driven by the dissociation of a host–guest complex. The hydrogel comprised a thermoresponsive linear polymer with adamantane as a guest molecule in its side chain and a nonthermoresponsive network structure with β-cyclodextrin as a host molecule. Immobilization of the thermoresponsive polymer in the hydrogel via host–guest interaction resulted in a partial restriction of its phase transition, even above its lower critical solution temperature (LCST). The hydrogel demonstrated a decrease in transmittance when mechanical stress was applied at a temperature above its LCST, indicating that the phase transition of the thermoresponsive polymer was induced by the dissociation of the host–guest complex under mechanical stress. Moreover, this mechano-responsive behavior was repeatable by cooling the hydrogel to redissolve the thermoresponsive polymer. The strategy of the mechano-responsive phase transition will be useful for various applications that demand the control of desired functions by applied stress.

Versatile Graphene Oxide Hybrid Supramolecular Hydrogel Driven by Host–Guest Interaction Showing Excellent Mechanical and Sensing Properties and Photothermal Responsiveness

“…This indicates that the introduction of GO significantly reinforces the mechanical properties of hydrogels . Due to the superstretch properties of P­(AM-G)/CB[8] hydrogel, the ultralong tensile of hybrid hydrogels should be mainly attributed to the host–guest interaction as “sacrificial bonds” . Moreover, the addition of GO does not cause a significant reduction in elongation, which can be attributed to the existence of hydrogen bonding between GO and P­(AM-G) making rigid GO sheets align along the tensile direction.…”

“…47 Due to the superstretch properties of P(AM-G)/CB [8] hydrogel, the ultralong tensile of hybrid hydrogels should be mainly attributed to the host−guest interaction as "sacrificial bonds". 48 Moreover, the addition of GO does not cause a significant reduction in elongation, which can be attributed to the existence of hydrogen bonding between GO and P(AM-G) making rigid GO sheets align along the tensile direction. Additionally, the GO sheets prevent effective crack propagation by suppressing the stress−concentration.…”

Supramolecular topological hydrogels: from material design to applications

“…3B). 70 This supramolecular hydrogel was prepared by utilizing a non-thermoresponsive network with β-CDs as host and a thermoresponsive PNIPAAm copolymer with Ad as guest. The dissociation of the supramolecular bonds of the host-guest complex was triggered by applying mechanical stress.…”

Bioinspired Adhesive Antibacterial Hydrogel with Self-Healing and On-Demand Removability for Enhanced Full-Thickness Skin Wound Repair

“…Host–guest chemistry is a rapidly expanding and highly versatile approach for constructing hydrogels due to its specificity, interaction strength, and controllable reversibility . Unlike chemically cross-linked hydrogels, hydrogels based on host–guest chemistry can undergo trigger separation in response to various environmental stimuli and self-heal when damaged. , The guest polymer and the host polymer can form multiple inclusion complexes . Cyclodextrins are widely selected as the host polymer due to their excellent biocompatibility.…”

“…23 Unlike chemically cross-linked hydrogels, hydrogels based on host−guest chemistry can undergo trigger separation in response to various environmental stimuli and self-heal when damaged. 24,25 The guest polymer and the host polymer can form multiple inclusion complexes. 26 Cyclodextrins are widely selected as the host polymer due to their excellent biocompatibility.…”