Mycelium Composite with Hierarchical Porous Structure for Thermal Management

High-performance porous materials with a low carbon footprint provide sustainable alternatives to petroleum-based lightweight foams and can help meet carbon neutrality goals. However, these materials generally face a trade-off between thermal management capabilities and structural strength. Here, a mycelium composite with a hierarchical porous structure, including both macro- and microscale pores, produced from multiple and advanced mycelial networks (elastic modulus of 1.2 GPa) binding loosely distributed sawdust is demonstrated. The morphological, biological, and physicochemical properties of the filamentous mycelium and composites are discussed in terms of how they are influenced by the mycelial system of the fungi and the way they interact with the substrate. The composite shows a porosity of 0.94, a noise reduction coefficient of 0.55 at a frequency range of 250-3000 Hz (for a 15 mm thick sample), a thermal conductivity of 0.042 W m^-1  K^-1 , and an energy absorption of 18 kJ m^-3 at 50% strain. It is also hydrophobic, repairable, and recyclable. It is expected that the hierarchical porous structural composite with excellent thermal and mechanical properties can make a significant impact on the future development of highly sustainable alternatives to lightweight plastic foams.