Temperature-Driven Pore Size Engineering in Multilayer Graphene/Polyimide Aerogels for Ultra-Broadband Electromagnetic Wave Absorption

Temperature-driven pore size engineering (4.4–33.5 μm) systematically optimizes electromagnetic wave absorption • Large pores mitigate excessive permittivity for impedance matching, while ultrafine pores compensate for insufficient intrinsic attenuation. • Genetic algorithm-optimized multilayer architectures achieve an exceptional minimum reflection loss of −68.85 dB at 3.5 mm and an ultra-broad effective absorption bandwidth of 14.05 GHz at 10 mm. While the pore architecture of aerogels significantly impacts electromagnetic wave (EMW) absorption, current designs predominantly focus on pore orientation, leaving the quantitative relationship between pore size and electromagnetic performance largely unexplored. To bridge this gap, we develop cross-scale graphene/polyimide aerogels, integrating temperature-driven microscale pore size engineering with macroscopic multilayer configurations. At the microscale, tuning the freezing temperature enables systematic regulation of pore sizes from 4.4 to 33.5 μm, thereby elucidating a complementary loss mechanism wherein large pores mitigate excessive permittivity to optimize impedance matching, while ultrafine pores compensate for insufficient intrinsic attenuation. Consequently, the optimal single-layer aerogel achieves an effective absorption bandwidth ( EAB ) of 7.05 GHz, alongside a minimum reflection loss ( RL min ) of −54.58 dB. At the macroscale, a genetic algorithm is employed to systematically explore the parameter space—encompassing pore size, thickness, and filler loading—to construct optimized multilayer architectures. The resulting multilayer aerogels (MAs) exhibit a remarkable RL min of −68.85 dB alongside an EAB of 8.83 GHz at 3.5 mm, while achieving an ultra-wide EAB of 14.05 GHz coupled with a strong RL min of −54.63 dB at 10 mm. Furthermore, the optimized MAs demonstrate an exceptional radar cross-section reduction capability of up to 45.91 dB, establishing a robust design paradigm for next-generation EMW absorbers. Download: Download high-res image (281KB) Download: Download full-size image