Characteristics of polyimide/barium titanate composite films

In this study, the characteristics of the polyimide/BaTiO3 composite films with various amounts of BaTiO3 were evaluated. Modifier 1-methoxy-2-propyl acetate was added during composite preparation to disperse the BaTiO3 particles in polyimide matrix. Conversion of polyamic acid (PAA) to polyimide was not completed for the composite film with a high BaTiO3 loading (90 wt%). Dielectric constant of the film increases from 3.53 to 46.50, at the sweep frequency of 10 kHz, as the BaTiO3 content increases from 0 to 90 wt% (0–67.5 vol.%), which is mainly due to the relatively high dielectric constant of BaTiO3 particles in the polyimide matrix. The dielectric losses at 10 kHz is ranging from 0.005 to 0.015, which is due to the switching of the domain wall. Water absorption decreases considerably with increasing BaTiO3 content. With 10 wt% (2.5 vol.%) BaTiO3 addition, the water absorption of the composite film reduces 45% from that of pure polyimide. Also, high loading of BaTiO3 is not beneficial to reduce the water absorption of the composite film.