Synthesis of surface conductive polyurethane films

Polyurethane films containing 3-methylthiophene were first prepared by the condensation of poly(propylene glycol) diol, poly(propylene glycol) triol and toluene 2,4-diisocyanate in the presence of a catalyst and 3-methylthiophene, at room temperature, overnight. The immersion of the films in a suitable organic solution of ferric chloride led to their rapid coating with conductive layers of poly(3-methylthiophene) via the diffusion-oxidative reaction of 3-methylthiophene and ferric chloride. The effects of the oxidative reaction time, the concentration of ferric chloride, the type of polyurethane, the solvent used for ferric chloride and the weight ratio of 3-methylthiophene to polyurethane were investigated. The coating layer was of the order of tens of micrometers and its conductivity was as high as 42 S/cm.