Optically reflective composite polyimide films have been prepared
by casting a dimethylacetamide solution of silver(I) acetate, hexafluoroacetylacetone,
and the poly(amic acid)
derived from 3,3‘,4,4‘-benzophenone tetracarboxylic acid dianhydride
(BTDA) and 4,4‘-oxydianiline (4,4‘-ODA) onto an fully imidized parent BTDA/4,4‘-ODA
base. Thermal curing
of the silver(I)-containing poly(amic acid) topcoat leads to
imidization with concomitant silver(I) reduction followed by silver(0) migration/aggregation yielding
a reflective, but not
conductive, silver surface. This “film-on-film” composite
approach minimizes the silver
required for the formation of a reflective surface and preserves the
essential mechanical
and thermal properties of the parent polymer. The metallized films
exhibit outstanding
metal−polymer and polymer−polymer adhesion, with the strong
metal−polymer adhesion
attributable to mechanical interlocking and/or encapsulation.
Films were characterized by
X-ray, DSC, TGA, XPS, TEM, and AFM.