Physically Interpenetrated PI ‐ ZrO 2 Dual‐Network Aerogels via Ambient‐Pressure Drying for Enhanced Thermal Insulation and Mechanical Performance

ABSTRACT Polyimide (PI) aerogels are prized for their high strength, excellent thermal stability, and low density—making them ideal for aerospace, electronic instruments, and sensor applications. Yet conventional PI aerogels suffer from poor structural integrity, inadequate thermal insulation, and dimensional instability, limiting their use in demanding environments. To address these challenges, this study reports the rational design and scalable fabrication of a PI–ZrO 2 double‐network interpenetrating aerogel via atmospheric‐pressure drying and physical interpenetration—avoiding energy‐intensive supercritical drying. The PI network was synthesized from 4,4′‐diaminodiphenyl ether (ODA) and 4,4′‐diamino‐2,2′‐dimethyl‐1,1′‐biphenyl (DMBZ) as diamine monomers, and 3,3′,4,4′‐biphenyltetracarboxylic dianhydride (BPDA) as the dianhydride, with 1,3,5‐benzenetricarbonyl chloride serving as a covalent crosslinker. Concurrently, a colloidal ZrO 2 network was generated in situ via hydrolysis and condensation of zirconium oxychloride in an alcohol–water mixture under controlled thermal conditions. The resulting PI–ZrO 2 interpenetrating network aerogel, fabricated under optimized synthesis parameters, exhibits a specific surface area of 322.31 m 2 /g, a volumetric shrinkage of merely 8.73%, a porosity of 94.01%, and an ultralow thermal conductivity of 29.4 mW m −1 K −1 . Microstructural characterization confirms uniform nanoscale pore distribution, while functional evaluation demonstrates synergistic enhancements in thermal insulation performance and compressive modulus. These attributes position the PI–ZrO 2 dual‐network aerogel as a highly viable candidate for thermal insulation applications.