High-Toughness\nEpoxy-Based Composites with a Bioinspired\nThree-Dimensional Interconnected Skeleton for Photothermal Conversion\nApplications

Advanced\nepoxy (EP)-based composites, retaining excellent physical\nand mechanical properties, are in demand in many high-end devices,\nsuch as fan blades of aeroengines. However, the irreconcilable conflict\nbetween stiffness and toughness within an EP often leads to catastrophic\nbrittle fracture. Herein, inspired by the medulla skeleton of wing\nfeathers of <i>Milvus migrans</i>, bioinspired EP-based\ncomposites (BECs) were obtained via integrating functionalized three-dimensional\ninterconnected skeleton into a brittle EP. The BEC’s fracture\ntoughness is enhanced by 111.43%. Significantly, the maximum fracture\ntoughness (<i>K</i><sub>JC</sub>) of the BEC is 3.5 times\ngreater than that of the EP. Moreover, under 100 mW/cm<sup>2</sup> irradiation, the BEC can be heated from room temperature to 90 °C\nin 5 min, exhibiting excellent photothermal conversion capacity. The\nBEC expands the possible applications of conventional EP-based composites\nin engineering materials and energy management fields. The proposed\nbioinspired strategy provides a new avenue to design novel EP-based\ncomposites with strong mechanical properties and multifunction integration.