RETRACTED ARTICLE: Formation of polyelectrolyte multilayer films with controlled wettability via layer-by-layer electric-assembly

Taking the positive charged poly (diallyldimethylammonium chloride), PDDA, and negative charged polymaleic acid, PMA, as raw materials, the polyelectrolyte multilayer film, PMF, with oppositely charged surfaces was prepared by the layer-by-layer electric-assembly, LBLEA, method. Experimentally, the applied voltage was varied and the electrostatic force, EF, was controlled in enhancement or reduction, respectively. Results showed that these PMFs have oppositely surface wettability because the PDDA surface was sensitively responded to the voltage increase with EF enhancement to form the hydrophobic C=C structure, and the PMA surface was oppositely sensitively responded to the voltage increase with EF reduction to form the hydrophilic Cl−–COOH structure, respectively. A related mechanism has been discussed by investigating the effect of voltage increase on the surface tension of these two polyelectrolyte solutions.