Nature-inspired architected materials have been widely used to achieve efficient structural materials by harnessing their cellular and hierarchical structures. For example, biological materials observed in bone, shell, nacre, and wood contain constituents, ranging from nanometers to centimeters, arranged in an ordered hierarchy. Because of their composited structures that contain micro and nanoscale building blocks arranged in an ordered hierarchy and the material size effect in the mechanical strength of nano-sized solids, bioceramic materials are mechanically robust and lightweight. The design principles offered by hard biological materials of multiscale composite structures can assist in the creation of advanced ceramic architectures. In addition, the evolution of additive manufacturing technologies has enabled the fabrication of materials with intricate cellular architected materials. In this review, we discussed advanced additive manufacturing for the fabrication of nature-inspired multiscale ceramic structures by combining conformal thin-film coating technique with conventional additive manufacturing methods.

Microlattice is well known as an efficient structure having a low density which maintains mechanical properties, so microlattice is being applied to the structural design of lightweight material in many industrial fields. In this study, we proposed a core-shell microlattice structure by the conformal coating of a metal nanoparticle-polymer composite in order to enhance the mechanical properties of polymeric microlattice printed by light-based 3D printing method. Polymeric architected microlattice was fabricated using digital light printing, which enabled the printing of complex structures with good surface smoothness. Then, the polymeric microlattice was conformally coated with aluminum nanoparticle-polymer composites. To investigate the effect of the metal nanoparticle-polymer composite coating on the mechanical properties of the microlattice, we studied the compressive behavior of cubic and octet-truss microlattices. As a result, we confirmed that both compressive strength and toughness of the two types of microlattices were effectively increased by coating with aluminum nanoparticle-polymer composites.