Rigid-Flexible Dual-Network Aerogel Microfiber/Nanofiber Sponge with Warmth Retention and Electromagnetic Shielding

Facing the demand for wearable protective materials in some extreme environments, it is a challenge to develop lightweight and flexible materials with efficient warmth retention and electromagnetic (EMI) shielding. Here, a rigid-flexible dual-network aerogel fiber/nanofiber sponge (RAFS) is successfully constructed via a facile three-dimensional electrospinning strategy. Through regulation of the charged jet’s deformation and phase, the rigid PMMA/MWCNT–OH aerogel fibers and flexible TPU/Fe3O4 nanofibers are formed synchronously and further assembled into fibrous sponge with dual-network structures. Due to the dual-network structures, the sponge exhibits remarkable mechanical properties, including high stretchable (exceeding 2000 times its own weight), excellent elasticity after 1000 cycles of tensile or compressive process, and elastic recovery capability even at −196 °C. Moreover, the hierarchical pore structure enables RAFS to achieve ultralow density (4.74 mg cm–3) and the thermal conductivity of only 26.56 mW m–1 K–1. Furthermore, the synergistic effect of the conductive (MWCNT–OH) and magnetic (Fe3O4) networks endows RAFS with a rapid photothermal efficiency (surface temperature rises from 22 to 67.1 °C after 5 min) and good EMI shielding effectiveness (16.32 dB). Additionally, RAFS exhibits excellent hydrophobicity, heat insulation stability in humid environments, and long-term durability. This study provides a new strategy for developing lightweight and flexible multifunctional protective materials for extreme environments.