Characteristics of polyimide/barium titanate composite films

Abstract In this study, the characteristics of the polyimide/BaTiO 3 composite films with various amounts of BaTiO 3 were evaluated. Modifier 1-methoxy-2-propyl acetate was added during composite preparation to disperse the BaTiO 3 particles in polyimide matrix. Conversion of polyamic acid (PAA) to polyimide was not completed for the composite film with a high BaTiO 3 loading (90 wt%). Dielectric constant of the film increases from 3.53 to 46.50, at the sweep frequency of 10 kHz, as the BaTiO 3 content increases from 0 to 90 wt% (0–67.5 vol.%), which is mainly due to the relatively high dielectric constant of BaTiO 3 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 BaTiO 3 content. With 10 wt% (2.5 vol.%) BaTiO 3 addition, the water absorption of the composite film reduces 45% from that of pure polyimide. Also, high loading of BaTiO 3 is not beneficial to reduce the water absorption of the composite film.