| Abstract
| - We report the observation of the reversible adsorption of core−shell gold−silver nanoparticles at the polarizedwater/1,2-dichloroethane interface using the nonlinear optical technique of surface second-harmonic generation.This study unambiguously demonstrates the excellent stability against aggregation of these core−shellnanoparticles, namely, gold core nanoparticles coated with silver layers of variable thickness, in the presenceof an electrolyte salt like lithium chloride. Furthermore, it is also demonstrated that the adsorption of thenanoparticles is reversible by modulating the applied potential at water/1,2-dichloroethane interface. The analysisof these results is performed within the Debye−Hückel approximation of the electrostatic interactions betweenthe nanoparticles. This approach shows that the stability of core−shell nanoparticles can be attributed to theformation of a silver oxide layer at the surface of the particles.
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