Surface Modification-Based Fabrication of Double Surface Highly Reflective and Conductive Metallized Polymeric Films and Microstructural Tuning Nanocomposite Layers

Abstract

Silvered polyimide films have been prepared by alkali hydroxylation of polyimide film surface and incorporation of silver ions through subsequent ion exchange. Thermal curing had not only re-cycloimidized the poly(amic acid) into polyimide, but also reduced silver ions into silver atoms and near-atomic silver clusters, which diffused and aggregated to give reflective and conductive surfaces without addition of reducing agents. By this method, silvered polyimide films can be easily fabricated with double excellent reflective (reflectivity > 97%) and conductive surfaces (surface resistance: 0.02 /sq), outstanding metal-polymer adhesion, high mechanical properties, and controllable thickness of silver layers at modest cost. As the side-to-side near-surface microstructure difference in the laboratory made samples and commercial PI films, the thickness of alkali induced hydrolysis, loading of silver ions and forming of silver layers at the two sides of the polyimide films were also discussed here. Films were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM) and tapping mode atomic force microscopy (AFM). Results show that continuous silver layers were formed on the polyimide films.