Programmable 3D printing orientation-induced toughening for biomimetic hierarchical ceramic composites

Natural structural materials exhibit superior mechanical performance compared to conventional synthetic composites, originating from their intricate multiscale hierarchical architectures with precisely aligned components. However, achieving controlled crack propagation to prevent catastrophic failure remains a challenge, as the current unidirectional structural designs limit the fracture toughness of composites. This study proposes an orientation-controllable nanoplatelet 3D printing method, enabling programmable control over both vertical and horizontal alignment of ceramic nanoplatelets within printed filaments. By changing the number and alignment sequence of the vertical and horizontal orientation layers, diverse biomimetic ceramic architectures were successfully fabricated. Further, polymer composites were fabricated through surface functionalization with polydopamine coatings. Mechanical evaluation demonstrates that alternating horizontal and vertical alignment composites possess enhanced strength (181.6 MPa) and toughness (6.02 MPa·m 1 / 2 ), representing a 2-fold increase in strength and a 1.5-fold improvement in toughness compared to horizontal lamellar alignment composites. This research providing guidance for tailoring biomimetic composite properties.