Fabrication of Aminopropyl POSS End Capped Polyimide Hybrids for Enhanced Hydrophobicity and Reduced Dielectric Properties

Abstract Recently, research on organic–inorganic hybrids made from polyimide (PI) and polyhedral oligomeric silsesquioxane (POSS) nanoparticles has attracted considerable attention due to their exceptional properties, including low water absorption, high thermal stability, and low dielectric properties. This study explores the incorporation of POSS nanoparticles into PI matrices through covalent bonding and evaluates their impact on the physical properties of the PIs. Low‐dielectric constant and low‐dielectric loss PIs are synthesized using a simple approach that incorporates functionalized POSS molecules to introduce porosity and secondary relaxation behaviors into the polymer chains. Integrating POSS into the 1,2‐diphenylethane‐1,2‐diyl bis(4‐aminobenzoate) (HBABA)/4,4′‐(hexafluoroisopropylidene) diphthalic anhydride (6‐FDA) PI (HBF PI) matrix significantly reduced the dielectric constant (D k ) (at 1 MHz) of the HBF PI‐POSS (hereafter designated as HBFP) hybrids from 2.61 to 2.33, while maintaining stable loss tangents even up to 2.5% POSS content. In addition, the HBFP nanohybrids exhibited high water repellency.