Preparation and properties of mesoporous SiO2/polyimide composite films.

Although polyimide films have a low dielectric constant, with the advent of the 5G era, the dielectric properties of the material are required to be further improved. Therein, we prepared controlled hollow mesoporous SiO2 nanomicrospheres by the hard template method to make mesoporous low dielectric polyimide films. The composite membrane exhibits better thermal stability, mechanical properties, and hydrophobicity compared to the pure membrane. Hollow mesoporous SiO2 dispersed in polyimide can reduce the inhomogeneity of charge distribution between molecules and reduce the interaction between polar chemical bonds and aromatic rings, thus improving the dielectric properties of the whole film. The minimum dielectric constant of the composite films was 2.80 when the hollow mesoporous SiO2 was added at 1.0%. These results fully indicate that the addition of hollow mesoporous SiO2 is beneficial to the multifaceted performance of the polyimide films. Highlights: Preparation of hollow mesoporous SiO2 microspheres by using different polystyrene microsphere solutions and TEOS ratios.Synthesis of composite films with different contents of hollow mesoporous SiO2 as functional fillers.The effect of hollow mesoporous SiO2 content on the mechanical properties and thermal stability of PI composite films was investigated.Addition of hollow mesoporous SiO2 reduces the dielectric constant of polyimide composite films. [ABSTRACT FROM AUTHOR]