The use of chemical fuels in nonequilibrium assembly is ubiquitous in nature but much less common in abiotic systems. Here, chemically fueled and transiently crosslinked polymer materials were synthesized using the hydration of carbodiimides to link pendant carboxylic acids as anhydrides. Our design is based on simple acrylamide and acrylic acid copolymers. The covalent crosslinking was fueled using EDC. Beginning with aqueous polymer solutions, we observe the formation of hydrogels, which dissolve as the anhydrides are hydrolyzed. Both the mechanical properties and lifetimes of the gels are determined by the proportion of acid groups in the starting polymers. The gels exhibit higher storage moduli compared to previously reported transient supramolecular gels as a result of their covalent cross-links. The polymers can also undergo subsequent refueling cycles to regenerate the gel state. Small molecule, macroscopic and rheological properties of this reaction were investigated, showing that this is a powerful platform for materials which need temporary changes in mechanical properties.

Chemically fueled covalent crosslinking of polymer materials

2019 Spring National Meeting

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