ABSTRACT
Abstract A direct ion-exchange self-metallization technique is used to prepare a surface silver-metallized polyimide (PI) film. The method involves performing an ion-exchange reaction of damp-dry poly(amic acid) films in silver aqueous solution to form silver(I)-containing precursor films. Thermal treatment under tension converts the poly(amic acid) into polyimide and simultaneously reduces the silver(I) to silver(0), yielding silver (Ag) layers with excellent reflectivity and conductivity on both film sides. This work focuses on the influence of polyimide structure, the kind of silver salt, ion-exchange time and the curing conditions on the morphology and properties of films. Three polyimide matrices derived from 3,3′,4,4′-benzophenonetetracarboxylic dianhydride (BTDA)/4,4′-oxydianiline (ODA), 4,4′-oxydiphthalic anhydride (ODPA)/ODA and pyromellitic dianhydride (PMDA)/ODA and two silver salts, silver nitrate (AgNO3) and silver fluoride (AgF), were investigated. XRD, TEM, SEM, XPS and AFM measurements were used to characterize the structure and morphology of polyimide/silver composite films. The results show that films prepared from BTDA/ODAbased polyimide and AgF are more efficient to obtain highly reflective and conductive films than the others.
