Triphase polyimide nanocomposite films were fabricated using barium titanate (BaTiO

3

) with high dielectric constant and silver (Ag) with high conductivity as fillers.

In situ

method was utilized to obtain the homogeneous dispersion of nanoparticles. The

in situ

polymerization of polyimide precursor-poly(amic acid) was performed in the presence of BaTiO

3

particles. Silver compound 1

1

1-trifluoro-2

4-pentadionato silver(I) was added into the BaTiO

3

containing poly(amic acid) solution to achieve silver nanoparticles

via in situ

self metallization technique. The thermally induced reduction converted silver (I) to metallic silver with concomitant imidization of poly(amic acid) to polyimide. Both BaTiO

3

and silver nanoparticles were uniformly dispersed in the polyimide substrate. The dependence of dielectric behavior on the BaTiO

3

and Ag contents was studied. The incorporation of small amount of silver nanoparticles greatly increased dielectric constant of composite films.