Transient and Dissipative Host–Guest Hydrogels Regulated by Consumption of a Reactive Chemical Fuel

The transient self‐assembly of molecules under the direction of a consumable fuel source is fundamental to biological processes such as cellular organization and motility. Such biomolecular assemblies exist in an out‐of‐equilibrium state, requiring continuous consumption of high energy molecules. At the same time, the creation of bioinspired supramolecular hydrogels has traditionally focused on associations occurring at the thermodynamic equilibrium state. Here, hydrogels are prepared from cucurbit[7]uril host–guest supramolecular interactions through transient physical crosslinking driven by the consumption of a reactive chemical fuel. Upon action from this fuel, the affinity and dynamics of CB[7]–guest recognition are altered. In this way, the lifetime of transient hydrogel formation and the dynamic modulus obtained are governed by fuel consumption, rather than being directed by equilibrium complex formation. A new route to prepare dynamic hydrogel materials has been developed that uses a reactive and consumable chemical stimulus to temporarily upgrade host–guest affinity and drive hydrogelation. These hydrogels exist only transiently, autonomously transitioning back to a flowing suspension over time.