A previous article (Southward and Thompson, Chem Mater 2004, 16, 2091) focused on the characterization of surface metallized palladium-BTDA/4,4'-ODA (3,3',4,4'-benzophenone tetracarboxylic dianhydride-4,4'-oxydianiline) hybrid membranes formed by in situ reduction of Pd2+ to Pd-O during thermal imidization of the poly(amic acid) via the protocol of St. Clair et al. (J Am Chem Soc 1980, 102, 876). The present work extended the Pd-polyimide metallization synthesis to the BPDA/4,4'-ODA (3,3',4,4-biphenyltetracarboxylic dianhydride-4,4'-ODA) polymer. The effects of the Pd2+ ligand on the reductive metallization of BTDA/4,4'-ODA were also examined for the PdCl2(SMe2)(2), PdBr2(SMe2)(2), and Pd(CF3COO)(2) complexes. The hybrid films were characterized by specular and diffuse reflectivity and by conductivity measurement. Maximum specular reflectivity was in the range of 35%-55%, and conductivity was in the range of 1-10 Omega/square. Scanning electron microscopy and transmission electron microscopy revealed that the initial Pd metal particles formed within the films were in the 3-8 nm range in size. These particles increased in size with irregular shapes at the surface as the metallic exterior emerged. A fraction of the nanometer-sized Pd particles remained uniformly distributed throughout the bulk of the film. The mechanism for the formation of a metallic surface required selective oxidative degradation of the polyimide at the polyimide-air interface. (c) 2006 Wiley Periodicals, Inc.