SYNTHETIC STRATEGIES IN THE FORMATION OF IRON-MODIFIED POLYIMIDE FILMS

Composite polyimide films were prepared by casting and thermally curing a viscous homogeneous solution of either a poly(amide acid) or a poly(amide ester) doped with either tris(acetylacetonato)iron(III) or trihydrogen hexachloroiron(III). The various polyimide precursors (with or without coordination sites) and iron dopants (of different thermal stability) were chosen to examine their effect on the formation of iron-rich surface layers and dopant bulk particle size after curing. Films prepared with both polyimide precursors and Fe(acac)3 Produced materials with very small bulk particles and no iron-rich surface layers. Films produced with both polyimide precursors and H3FeCl6 produced large bulk particles and surface layers of iron oxide. Films prepared, however, with H3FeCl6/poly(amide ester) solutions had larger surface layers than films prepared from H3FeCl6/poly(amide acid) solutions.