Effects of iron(III) p-toluenesulfonate hexahydrate oxidant on the growth of conductive poly(3,4-ethylenedioxythiophene) (PEDOT) nanofilms by vapor phase polymerization

Study of the effects of evaporation time and oxidant concentration on the polymerization rate and final thickness of poly(3,4-ethylenedioxythiophene) (PEDOT) films found that the polymerization was chemical reaction limited, and that the final film thickness was linearly dependent on oxidant concentration. The influence of spin-coated iron(III) p-toluenesulfonate hexahydrate (Fe(PTS)3) oxidant solution on the polymerization and resulting PEDOT structures was also investigated. Spin-coated low-density (1.35 g/cm3) Fe(PTS)3 oxidant solution, consisting of highly anisotropic paracystalline structures, provided open frameworks for the growth of conducting polymers, leading to a-axis oriented paracrystalline PEDOT films. Polymerization proceeded through the oxidant framework, increasing the density of PEDOT-filled oxidant solution to 2.01 g/cm3 with negligible change of thickness. Furthermore, the formation of a surface organic layer, as a result of spinning, promoted uniform and smooth PEDOT films.