Self-assembled poly(metal tetrathiooxalate) films

Ultrathin poly(metal tetrathiooxalate) films are described which were prepared by a reactive self-assembly process. The polymer films were prepared upon alternate dipping of a negatively charged substrate into aqueous solutions of transition metal salts (e.g. salts with Cu2+, Ni2+, Co2+ and Pd2+) and tetraethylammonium tetrathiooxalate, which led to sequential adsorption of the metal and tetrathiooxalate ions under simultaneous complexation and formation of poly(metal tetrathiooxalate). The polymer films exhibit a brownish coloration with strong metallic reflection. Optical measurements indicate a very broad absorption extended from the ultraviolet to the near-infrared up to 2000 nm. Scanning force microscopy indicates a rather smooth surface with isolated peaks of a height up to 2 μm. Preliminary studies of the specific surface conductivity of poly(nickel tetrathiooxalate) films indicate a value of 2.5×10−3 S cm−1.