Effect of content on dielectric performance of polyimide / TiO2 hybrid films

In situ polymerized polyimide/TiO₂ composite films with good electrical performance are studied. These nanocomposite films are also characterized by scanning electron microscopy (SEM). SEM analyses show that the spherical shaped titania particles and the ceramic particles distribute uniformly in the matrix of hybrid film. Dielectric properties of the films are measured in the frequency range of 102Hz-105 Hz by an impedance analyzer at room temperature. The dielectric constant varies with the sweeping frequency and filler content and it decreases with sweeping frequency. It is demonstrated that the breakdown strength reaches its maximum value when the content of filled TiO₂ is 0.5 wt.%, and then decreases with the increase of the concentration of the filler.