Voltammetry and FTIR-ATR techniques have been employed to investigate polyphenol films formed on platinum surfaces by electrochemical oxidation of phenol. The media used in the electropolymerization were aqueous carbonate solutions, with and without Na2S. The polymeric films created are not permeable to ferrocyanide and ferricyanide species and present low water mobility. The presence of sulfide in the electropolymerization solution enhances these characteristics. The amount of sulfur detected by an energy dispersive X-ray detector (EDX) in the polymeric films created in the presence and in the absence of sulfide in the solution is very similar. Thus, the sulfur present in the polymer created in solutions with a sulfide concentration up to 10(-3) M is not representative. A strong stretching vibration band at 900-1150 cm(-1) is obtained in the IR spectrum that can be associated to the ether linkages of the phenolic rings (=C-O-C=).