Nonequilibrium regulation of interfacial chemistry for transient macroscopic supramolecular assembly

Hypothesis: Macroscopic nonequilibrium assembly helps to interpret the interfacial assembly mecha-nism and promotes the creation of self-adaptive chemical systems for potential applications such as con -trolled release and mass transfer. We propose that the precise macroscopic nonequilibrium assembly can be achieved by rationally integrating pH-responsive hybrid polymer hydrogels with the urea-urease clock reaction.Experiments: Herein, pH-responsive and urease-containing polyelectrolyte hydrogels were fabricated for achieving macroscopic nonequilibrium assembly. Optical microscopy was used to visualize the interface of the macroscopic assemblies. Tensile tests were performed to investigate the adhesion strength of the assemblies and the modulus of the hydrogels. The charges and electric field distribution at the hydrogel surface were estimated by zeta potential measurements. Furthermore, an in situ sewing-growing method for fabricating hybrid polymer hydrogels with modularized surface chemistry was presented to achieve precise nonequilibrium assembly.Findings: The realization of precise macroscopic nonequilibrium assembly relies on the transient electro-static attraction between the hybrid polymer hydrogels, which lays the foundation for yielding transient macroscopic supramolecular devices potentially useful for timed release. The stability and lifetime of the transient assemblies can be controlled by adjusting the hydrogel synthesis parameters and fuel compo-sitions, and the macroscopic nonequilibrium assembly can be repeated by refueling the system.(c) 2022 Elsevier Inc. All rights reserved.

Automated summary

Macroscopic nonequilibrium assembly is achieved by integrating pH-responsive hydrogels and urea-urease clock reaction, enabling precise assembly for controlled release and mass transfer applications. Transient electrostatic attraction between hybrid polymer hydrogels is crucial for the realization of macroscopic nonequilibrium assembly, which can be controlled and repeated by adjusting synthesis parameters and fuel compositions.