Ultrasound-Triggered Self-Assembly of Discrete Oligourethanes into Supramolecular Gels: Importance of Stereocenter Sequence.

Stereochemistry and the monomer sequence of biopolymers are key parameters that guide self assemblies and functions of biological systems. However, abiotic macromolecules are still behind in mimicking the selective interactions that drive the complexity of living matter. Herein, we report that synthetic, precise oligourethanes can form noncovalent assemblies leading to supramolecular gels. Notably, the process of supramolecular gelation occurs outside the aqueous environment and exhibits reversible adaptive behavior in response to external stimuli, including ultrasound and temperature. Gel formation and its properties are guided by the information encoded in the sequence and stereochemistry of their backbones and depend on the solvent environment. The performed spectroscopic studies reveal that the stereochemical control governing the oligourethane conformations, in turn, directs the higher-order assembly pathway. This work demonstrates the compelling property of abiotic oligourethanes that opens up opportunities to fine-tune self-assembly features using sequence control previously thought to be confined to biopolymers. Our findings open up new possibilities for designing synthetic polyurethane materials that can operate in nonphysiological environments while mimicking biopolymer features, thereby laying the foundation for applications in adaptive soft materials, organic-phase catalysis, and chemical sensing, utilizing ultrasonic-based technologies.