Fabrication Of Surface Silvered Polyimide Films In Hydrogen And Study Of Silver Migration And Polyimide Degradation

Surface silvered polyimide(PI) composite film has been prepared using pyromellitic dianhydride/4,4'-oxydianiline(PMDA/ODA)-based polyimide as the matrix and AgNO3 as the Ag precursor via hydrolysis and ion-exchange technique. Thermal treatment in various atmosphere cause the imidization of PAA, turn it into polyimide and at the same time converted Ag+ into Ag clusters, which diffused in the modified layer and aggregated or migrate onto the surface (depend on the atmosphere), giving rise to Ag layers. The formation and growth process of Ag nanoparticles and changes in crystal structure during thermal treatment were tracked. The results revealed when heated in air, the intensive degradation of polyimide dominates silver layer formation. It leads to a rather fast silver particles aggregating on surface when compared to those films prepared in hydrogen. The latter method provides excellent films indeed, nearly harmless to the PI matrix.Hydroquinone solution has been use to fabricate PI/Ag composite films in room temperature. PI/Ag composite film with high conductive and reflective properties was obtained.Changes in the chemical structure of the matrix film, the crystal structure and the size of the silver particles on surface in each step were analyzed by ATR-FTIR, XRD. ICP was used to investigate the ion-exchange process. SEM was used to study the aggregation of silver particles on the surface. TEM was used to investigate the formation of sliver layer and Ag particles distribution inside the matrix. The final nanocomposite films remain the major mechanical and thermal properties of the pure polyimide.