Ant‐Nest‐Inspired Biomimetic Composite for Self‐Cleaning, Heat‐Insulating, and Highly Efficient Electromagnetic Wave Absorption

Abstract The pursuit of eco‐friendly electromagnetic wave absorption (EMWA) materials with multifunctional capabilities has garnered significant attention in practical applications. However, achieving these desired qualities simultaneously poses a significant challenge. This study introduces a single‐step calcination and chemical polymerization process to obtain an environmentally friendly ant‐nest‐inspired hybrid composite by optimizing conductive polypyrrole nanotubes (PNTs) within a 3D carbonaceous structure. The biomimetic composite forms a highly efficient conductive network, providing a pathway for free electrons within the carbonaceous barriers and enhancing the conduction loss. Remarkably, the EMWA performance of the composite achieves ultrathin (1.6 mm), wide effective absorption band (5.4 GHz), and strong absorption intensity (−67.6 dB) features. Moreover, due to the complex and intertwined 3D continuous network, the obtained samples exhibit excellent thermal insulation and superhydrophobic behavior by inhibiting heat transfer and preventing localized areas from being prone to water absorption. These findings not only offer a sustainable and low‐cost production route for biomimetic carbonaceous composites but also demonstrate a high‐efficiency absorber with great multifunctionality as a green alternative to traditional EMWA materials.