Toughening Driven by Interphase Tuning in Bioinspired Nanocomposites: From Structural Engineering to Scalable Fabrication

Natural structural materials are built from a limited selection of components into complex hierarchical architectures spanning from the nanoscale to the macroscale. While these biological blueprints provide unique combinations of strength and toughness, replicating such mechanical performance in synthetic polymer nanocomposites remains a formidable challenge. A fundamental bottleneck persists as the decisive role of interphase tuning in driving robust toughening is frequently overlooked. Within these nanoscopic interphases, polymer chains exhibit fracture mechanics fundamentally distinct from the bulk phase, establishing the primary determinant for toughening against flexural deformation. This review evaluates interphase tuning as a pivotal mechanism for activating multiscale toughening through targeted energy dissipation and crack shielding. By assessing scalable manufacturing strategies such as layer-by-layer assembly and superspreading, we establish a robust methodology for engineering high-performance composites that bridge the gap between biological principles and structural applications.