Fabrication of flexible polyimide aerogels with extreme‑temperature resilience through a synergistic dual‑silicon approach

The structural rigidity inherent to polyimide (PI) aerogels, derived from their aromatic backbones, leads to a challenge for tailoring flexibility. This study addresses this limitation through a deliberate dual–silicon strategy that synergistically modulates molecular and nanoscale architecture. By integrating amine–propyl–terminated polydimethylsiloxane (APPS) into the PI backbone and dispersing silica nanoparticles within the matrix, we construct a hybrid network where flexible APPS segments enhance chain mobility while rigid silica nanoparticles provide reinforcement. This organic–inorganic synergy, coupled with directional freezing, yields an aerogel that achieves an exceptional balance of flexibility and robustness, enabling efficient resilience across an extreme temperature range from –196 to 250 °C. The material further exhibits multifunctionality, including ultra–low density (∼19.6–25.7 mg·cm⁻³), outstanding thermal insulation (overall thermal conductivity of 32.7–38.3 mW·m⁻¹·K⁻¹ at 25 °C), excellent flame retardancy (the limiting oxygen index of 30.2%), and efficient oil absorption over a broad temperature range (adsorption capacity of 60.2-68.3 g/g for dichloromethane at 25 °C, 31.7–32.0 g/g for pump oil at 200 °C, and 30.0–35.2 g/g for colza oil at 200 °C). This work demonstrates a principled approach to designing high–performance PI aerogels with tunable mechanics for extreme–environment applications.