Effect of cysteamine layer on the interaction between gold and ZrO₂ surfaces

The formation of cysteamine layer on gold surfaces may have an effect on the distribution of either gold particle adsorbed to the ZrO₂ surface or vice versa with the adjustment of the electrostatic interactions. The atomic force microscope (AFM) was used to measure the surface forces between the zirconia surface and the cysteamine surface s as a function of the salt concentration and pH value. With the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory, the forces were quantitatively analyzed to acquire the surface potential and charge density of the surfaces for each salt concentration and each pH value. The surface potential and charge density dependence on the salt concentration was described with the law of mass action, and the pH dependence was explained with the ionizable groups on the surface.