probably, PEDOT/PSS film on PET and polyester substrates exhibit the the same sheet resistance, because they were submitted to the same annealing treatment, which led to the same evaporation rate of PSS and enhancement of the PEDOT fraction on the surface polyester substrate, after standard annealing treatment, there was still the presence of glycerol on the surface due to the high roughness of the substrate with valley regions that act as deep wells .