Study on micro-morphology of inorganic phase and dielectric properties of polyimide hybrid films

In this paper, silica-alumina/polyimide hybrid films were prepared by sol-gel method. The micro-morphology of the inorganic phase of the films were characterized by Atomic Force Microscope (AFM). The dielectric properties of hybrid films were measured by Agilent-4294 precision impedance analyzer. The results indicate that average particle diameter increased with augmentation of proportion of silica to alumina. When the proportion of silica to alumina in the film was 8 to 1, inorganic phase took on network shape. However, the interphase between inorganic phase and polyimide was illegible. Incorporating inorganic particles into polymide had great effect on dielectric properties. Dielectric constant and dielectric loss angle diminished when the frequency increased. When the content of SiO₂ increased dielectric constant and dielectric loss angle increased at the same frequency.