We describe here the effect of an oil-in-water emulsion on the cyclic voltammetry of a redox probe at a platinum electrode coated with poly(3-methylthiophene), PMeT, a material for which wetting properties can be tuned by controlling its oxidation (charging) level. When a water soluble redox probe, such as potassium ferrocyanide or hexaammineruthenium(III) chloride, is mixed in an oil-in-water emulsion, the current response of the probe at Pt/PMeT decreases to less than 10%, consistent with adsorption of the disperse phase (oil + surfactant) at the polymer. On switching the partly blocked PMeT to its oxidized state, this polymer turns hydrophilic, decreasing the hydrophobic interaction between the polymer and the adsorbed oil particles. Removal of oil from the film is facilitated by electrostatic repulsion between the charged film and the surfactant bound to the oil phase, as indicated by the reappearance of the characteristic current signal at Pt/PMeT in an aqueous solution of the probe.