Fabrication of surface silvered polyimide/iron oxide composite films with both superparamagnetism and electrical conductivity

Surface silvered polyimide (PI)/Fe₂O₃ composite films with both superparamagnetic and surface electrically conductive properties have been fabricated by an in situ technique. Iron (III) 2,4-pentanedionate was incorporated into a PI precursor poly(amic acid) solution and thermally decomposed to form iron oxide nanoparticles in the process of thermal imidization, preparing PI/Fe₂O₃ nanocomposite films. The establishment of a silver layer on the PI/Fe₂O₃ film surface involved the steps of chemical etching by the alkaline aqueous solution, ion exchange with silver ions and chemical reduction by glucose. The formed Fe₂O₃ particles of the nano scale endow the film with typical superparamagnetic response. By employing the etching time of only 10 min and a reduction time of no more than 15 min, the well-established silver layers have formed on the upside surface. The corresponding reflectivity and resistivity reached to the value of 76.15% and 0.7 Ω/square respectively.