Preparation of hollow mesoporous silica/polyimide composite films and study of their properties

Abstract Constructing high‐performance polyimide (PI) films with low dielectric constant, excellent mechanical properties, hydrophobicity, and thermal stability is of great significance, but remains a great challenge. Herein, five PI films (labeled as P1, P2, P3, P4, and P5, respectively) were successfully synthesized by a conventional two‐step method using 1,4‐bis(4‐amino‐2‐trifluoromethylphenoxy)benzene as the sole diamine monomer and pyromellitic dianhydride, 2,3,6,7‐Naphthalenetetracarboxylic 2,3:6,7‐Dianhydride, 3,3′,4,4′‐biphenyltetracarboxylic dianhydride, o‐4,4′‐oxydiphthalic anhydride, and 3,3′,4,4′‐benzophenonetetracarboxylic dianhydride as dianhydride monomers, respectively. Particularly, a hollow mesoporous silica (HMSMs)/PI film with excellent comprehensive properties was successfully synthesized by introducing HMSMs into P4 film based on a polymerization strategy. The results showed that doping HMSMs contributed to reducing the dielectric constant, improving the mechanical properties and hydrophobicity, and maintaining the excellent thermal stability in comparison to the conventional P4 film. When the HMSMs content was 1.5 wt.%, the thermal decomposition temperature, tensile strength, water contact angle, and dielectric constant of the HMSMs/PI composite films were measured at 489°C, 162 MPa, 86.45°, and 2.40, respectively. This study presents a new approach for preparing advanced PI composite films. Highlights High‐performance HMSMs/PI composite films were synthesized. Doping HMSMs into PI enhances the overall performance of film. A lower dielectric constant (2.40) was achieved.