Coaxially Printing of Biomimetic Self‐Healing Silicate-Epoxy Composites

Most self-healing methods for engineering materials suffer from discontinuous distribution, delayed healing processes, and insufficient filling rates. In this study, a multi-component coaxial printing methodology was developed to synchronously construct silicate and epoxy components into self-healing engineering composites with a biomimetic vascular structure. This method directly creates an internal three-dimensional repair network, enabling the functionalization of multi-material systems and biomimetic structures while significantly enhancing their mechanical properties. The continuous "veins" filled with fluid epoxy resin provided an ample supply of the healing agent, which can rapidly diffuse into cracks upon internal damage. Simultaneously, the silicate mixture containing epoxy resin B induced the in situ curing of epoxy resin A, effectively repairing various fracture damages. Compared to the primary undamaged sample, the repaired silicate composite even demonstrated 50 % increase of maximum compressive strength. Microstructural characterization revealed the formation of an interpenetrating structure between the repaired epoxy resin and the silicate matrix, which endowed the repaired composite with higher strength than the pure silicate system. Additionally, numerical simulations further validated the strengthening and toughening mechanisms. The successful application of transparent silicate engineering materials also validated the efficacy of this coaxial 3D printing method, offering a novel technological pathway for the functionalization and structural design of other biomimetic engineering materials.