Solution-processable polyimide aerogels with high hydrophobicity

Hydrophobic polyimide aerogels with high solubility were prepared by combining sol-gel technology and supercritical CO2 extraction. Polyimide gels were derived from hybrid diamines 4, 4′-oxydianiline (ODA) and 2, 2-Bis [4-(4-aMinophenoxy) phenyl] propane (BAPP) with chemical imidization. Introduction of BAPP enhanced the hydrophobicity and water resistance of the obtained polyimide aerogels, as well as the solution-process ability. Overall, the obtained polyimide aerogels have low thermal conductivity in the range of 0.032-0.059 W/mK. Comparing to the conventional polyimide aerogels, solution-processable polyimide aerogels with high hydrophobicity are more applicable as thermal insulators in harsh environments.