Design of Bioinspired Highly Aligned Bamboo-Mimetic Metamaterials With Structural and Functional Anisotropy

Abstract

Metamaterials have received widespread attention for their unique properties and broad application prospects. With inspiration from bamboo, metamaterials can be rationally designed to achieve anisotropic functionality. Using a combination of 3D printing and subsequent hot pressing of dual-curing composites, we describe a simple method for creating well-aligned SiC whisker (SiCw) composites that mimic bamboo and have achievable anisotropic thermal conductivity (TC), dielectric properties (DP), and flashover performances (FP). The anisotropic structure is proved by scanning electron microscope and X-ray diffraction observations. At the low loading of 8 vol% SiCw, the axial thermal conductivity of the structured composites can reach 0.655 W m-1 K-1, whereas the radial thermal conductivity is only 0.281 W m-1 K-1, with a high anisotropic TC ratio of 2.33. Strong anisotropy in the dielectric constant was also observed with the permittivity of 134 along the axial direction versus that of 65 along the radial direction at 1 kHz, with a high anisotropic DP ratio of 2.06. Notably, metamaterials exhibit significant anisotropy in both their surface conductivity and flashover voltage, with a high conductivity ratio of ~10,000. The flashover voltage in the diametrical direction is 6 times that in the axial direction and 60% higher than that of the neat resin. This study shows that this approach is anticipated to offer a new path for the creation of high-performance functionally anisotropic materials to meet the diversified requirements of modern electronics.