Formation of Highly Electrically Conductive Surface-Silvered Polyimide Films Under Exceptionally Mild Conditions

This study attempted to improve upon a previously reported route to room-temperature metallization of a polyimide substrate. The silver(I)-triflate complex used to dope the polymer was replaced with a silver(I)-hexafluoroacetylacetone complex to remove the possibility that residual triflic acid would compromise the structural integrity of the polymer film. The results were initially very promising, showing conductivity and reflectivity values comparable or improved with the new complex versus the old. Furthermore, cracking observed with the triflate films did not occur. The conductivity was modeled as a function of several parameters allowing the entire metallization process to be optimized. Though macroscopic characterization suggested the two films were similar in nature, microscopy revealed significant differences between films from the two complexes. SEM showed a more textured surface for the Ag-HFA, suggesting more nucleation sites. TEM, however, showed that the Ag-HFA films have thin silver layers, indicating that some silver remains unreduced. Thus, it appears that there is a ligand effect in this process, and hence many new silver complexes and salts can now be studied.