We have a new paper out in J. Am. Chem. Soc.! In this work, Chamoni, Corvo, and co-workers explore polymer network hydrogels that can be temporarily mechanically reinforced on treatment with a carbodiimide through the formation of anhydride cross-links. Because these materials undergo gel–gel transitions, they exhibit new and unusual behavior. For example, two pieces can be temporarily and repeatedly adhered, with the time of adhesion dependent on the amount of carbodiimide used. Films can also be reversibly patterned with different mechanical properties. This work is part of our long-running collaboration with the Konkolewicz group.