Nonequilibrium Regulation of Interfacial Chemistry for Dissipative Supramolecular Assembly of Macroscopic Hydrogels

The nonequilibrium assembly in nature exists at the microscopic and macroscopic scales, and represents the most common way to regulate object motions by consuming chemical fuels. In artificial nonequilibrium systems, most of the work has focused on the microscopic dissipative assembly, whereas the investigation on nonequilibrium assembly of macroscopic building blocks is rarely reported. Here, we present an efficient strategy to dynamically mediate the interfacial chemistry of pH-responsive polyelectrolyte hydrogels, thereby regulating their macroscopic nonequilibrium assembly. The driving force for the assembly is the transient electrostatic attraction, which is regulated by the biocatalytic feedback-driven temporal programming of the pH of the system. The dissipative assembly process can be controlled by adjusting the hydrogel parameters and fuel composition and it can be repeated by refueling the system. Most importantly, the ordered sewing of complementary hydrogels promotes the precise nonequilibrium supramolecular assembly to yield transient macroscopic supramolecular devices potentially useful for timed release.