Meso-Engineeringof Supramolecular Fibers

Abstract Hierarchical molecular assemblies that evolve into fibrous mesoscale architectures are ubiquitous in nature and have attracted growing attention in the supramolecular materials field due to their distinctive functions and broad application potential. These hierarchical structures are often initiated by the formation of fibrous primary assemblies, which are further organized into higher-order structures through hierarchical processes. The exceptional properties of natural hierarchical architectures stem from the precise spatial arrangement and regulated organization of building blocks across multiple levels. However, reproducing such structural precision in synthetic supramolecular systems remains a formidable challenge, primarily due to the lack of established strategies to control the weak and nondirectional interactions that dominate at higher hierarchical levels. In this Perspective, we highlight two emerging concepts─macromolecular crowding and secondary nucleation─as promising design principles for constructing and controlling fibrous hierarchical molecular assemblies. Recent studies suggest that these phenomena, once thought to be relevant primarily in biological contexts, can also be applied to synthetic supramolecular systems, offering a new direction for the design of functional supramolecular architectures with mesoscale order and complexity.